Companhia De Saneamento Basico Do Estado De Sao Paulo-Sabesp
One of the largest water and sanitation companies in the world, this Brazilian utility delivers drinking water and sewage treatment to tens of millions of people across the state of São Paulo. Founded in 1973, it was created by merging several state-run water and sewage agencies into a single organization. Its name is simply a clever acronym: Sabesp comes from its Portuguese title, Companhia de Saneamento Básico do Estado de São Paulo.
Sponsored ADR
20-F · Fiscal year ended Dec 31, 2025 · SEC filing ↗
The original filing sections are available below.
Market Risk We are exposed to various market risks, in particular, foreign currency risk and interest rate risk. We are exposed to foreign currency risk because a portion of our financial indebtedness is denominated in foreign currencies, primarily the U.S. dollar, while we gene…
Market Risk We are exposed to various market risks, in particular, foreign currency risk and interest rate risk. We are exposed to foreign currency risk because a portion of our financial indebtedness is denominated in foreign currencies, primarily the U.S. dollar, while we generate all of our operating revenue in reais. Similarly, we are subject to interest rate risk based upon changes in interest rates, which affect our net financial expenses. For more information on our market risks, see Note 5.1(a) to our 2025 Consolidated Financial Statements included in this annual report. Exchange Rate Risk As of December 31, 2025 and 2024, R$10,632.3 million and R$3,356.4 million, or 26.5% and 13.3%, respectively, of our debt obligations were denominated in foreign currencies. As a result, we are exposed to exchange rate risks that may adversely affect our financial condition and results of operations, as well as our ability to meet debt service obligations. We entered into hedge transactions in 2025 to protect us against such risk, as detailed to Note 19 to our 2025 Consolidated Financial Statements included in this annual report. 140 Table of Contents Exchange Rate Sensitivity We estimate that the potential loss to us in connection with U.S. dollar, Euro and Yen-denominated debt that would have resulted as of December 31, 2025, 2024 and 2023 from each hypothetical instantaneous and unfavorable 1% change in the U.S. dollar, Euro and Yen against the real would have been R$106.3 million, R$33.6 million and R$27.5 million, respectively. Consistent with these estimates, a hypothetical instantaneous and unfavorable 10% change in this exchange rate would have resulted in losses of R$1,063.3 million, R$335.6 million and R$274.6 million as of December 31, 2025, 2024 and 2023, respectively. The fluctuation of the real in relation to the U.S. dollar and Yen for the years ended December 31, 2025, 2024 and 2023 were: Year ended December 31, 2025 2024 2023 (in percentages) Depreciation (appreciation) of the real in relation to the U.S. dollar (11.1) 27.9 (7.2) Depreciation (appreciation) of the real in relation to the Yen (11.0) 15.3 (13.5) Depreciation (appreciation) of the real in relation to the Euro 0.5 27.9 (7.2) During the year ended December 31, 2025, we entered into derivative instruments (plain vanilla swaps), with expiration dates ranging from 2030 to 2048, to fully protect us against a devaluation of the real against the U.S. dollar, the Yen, and the Euro. For more information regarding foreign currency risk and all derivatives financial instruments, see Notes 5.1(a) and 19, respectively, to our 2025 Consolidated Financial Statements included in this annual report. Interest Rate Risk As of December 31, 2025 and 2024, R$1,634.3 million, or 4.1%, and R$1,688.1 million, or 6.7%, respectively, of our total debt outstanding balance denominated in reais was based on variable rates of interest based on the Standard Reference Unit (Unidade Padrão Referência - “UPR”), which is equivalent to the Reference Rate (Taxa de Referência - “TR”) based on the Brazilian Federal Savings Bank. In addition, as of December 31, 2025 and 2024, R$19,854.9 million, or 49.5%, and R$15,670.7 million, or 62.0%, and respectively, of our total debt denominated in reais was subject to interest rates based on the CDI. As of December 31, 2025 and 2024, R$2,197.9 million and R$1,863.9 million, respectively, of our foreign-currency denominated debt was based on the IDB and the IBRD variable rates of interest, which are determined based on the cost of funding of these multilateral organizations in each period. As of December 31, 2023, we did not have any derivative contracts outstanding related to our exposure to changes in the UPR or the CDI or in the IDB or IBRD variable rates. We invest our excess funds, which totaled R$4,663.2 million and R$1,682.6 million as of December 31, 2025 and 2024, respectively, mainly in high liquidity short-term instruments. As a result, our exposure to Brazilian interest rate risk is partially limited by our real-denominated floating interest time deposits investments, which generally earn interest based on the CDI. In addition to our exposure with respect to existing indebtedness, we may become exposed to interest rate volatility with respect to indebtedness incurred in the future. We estimate that we would have suffered a loss over periods of one year, respectively, of up to R$401.4 million, R$252.6 million and R$195.4 million if a hypothetical instantaneous and unfavorable change of 100 basis points in the interest rates applicable to financial liabilities as of December 31, 2025, 2024 and 2023, respectively, had occurred. Consistent with these estimates, a hypothetical instantaneous and unfavorable 1000 basis points change in these interest rates would have resulted in losses of approximately R$4,014.2 million, R$2,525.8 million and R$1,953.6 million as of December 31, 2025, 2024 and 2023, respectively. This sensitivity analysis is based on the assumption of an unfavorable 100 basis point movement of the interest rates applicable to each homogeneous category of financial liabilities and sustained over a period of one year, as applicable, and that such movement may or may not affect interest rates applicable to any other homogenous category of financial liabilities. 141 Table of Contents A homogeneous category is defined according to the currency in which financial liabilities are denominated and assumes the same interest rate movement within each homogeneous category (i.e., U.S. dollars). As a result, our interest rate risk sensitivity model may overstate the effect of interest rate fluctuation on these financial instruments, as consistently unfavorable movements of all interest rates are unlikely. The tables below provide information about our interest rate-sensitive instruments. For variable interest rate debt, the rate presented is the weighted average rate calculated as of December 31, 2025. For the foreign currency denominated obligations, these amounts have been converted at the selling rates as of December 31, 2025 and do not represent amounts which may actually be payable with respect to such obligations on the dates indicated. Expected Maturity Date 2026 2027 2028 2029 and after Total Average Annual Interest Rate (in millions, except percentages) Assets Cash equivalents denominated in reais 4,663.3 - - - - - Liabilities Long-term debt (current and noncurrent portion) Floating rate, denominated in reais indexed by TR or UPR 138.8 142.6 151.4 1,201.5 1,634.3 8.1 % Floating rate, denominated in reais indexed by TJLP 262.1 246.0 87.2 231.3 826.6 7.2 % Floating rate, denominated in reais indexed to the IPCA 402.2 973.6 347.3 5,193.7 6,916.8 11.9 % Floating rate, denominated in reais indexed by CDI 3,760.7 598.1 849.4 14,646.7 19,854.9 15.3 % Fixed rate, denominated in reais 157.3 8.1 17.9 94.1 277.4 10.0 % Floating rate, denominated in euros 12.0 — — 1,438.5 1,450.5 4.0 % Floating rate, denominated in U.S. dollars 134.9 90.0 90.0 3,847.9 4,162.8 5.6 % Fixed rate, denominated in Yen 159.6 201.0 251.1 1,513.6 2,125.3 1.8 % Fixed rate, denominated in U.S. dollars 65.1 — — 2,828.5 2,893.6 5.6 % Total long-term debt 5,092.8 2,259.5 1,794.4 30,995.6 40,142.3 11.4 % UPR is equal to TR, which was 0.1742% per month as of December 31, 2025; CDI stands for Interbank Deposit Rate (Certificado de Depósitos Interbancários), which was 14.32% per annum as of December 31, 2025; IGP-M was -1.05% per annum as of December 31, 2025; TJLP stands for Long-term Interest Rate (Taxa de Juros a Longo Prazo), published quarterly by the Central Bank, which was 9.07% per annum as of December 31, 2025. The percentage of our indebtedness subject to fixed and floating interest rate is as follows: As of December 31, Floating rate debt: 2025 2024 2023 Denominated in U.S. dollars 10.4% 4.0% 4.2% Denominated in reais 72.8% 84.8% 83.6% Denominated in euros 3.6% - - 142 Table of Contents Fixed rate debt: Denominated in reais 0.7% 1.9% 2.3% Denominated in U.S. dollars 7.2% 3.3% 2.7% Denominated in Yen 5.3% 6.0% 7.2% Total 100.0% 100.0% 100.0%
A. [Reserved] B. Capitalization and Indebtedness Not applicable. C. Reasons for the Offer and Use of Proceeds Not applicable. D. Risk Factors You should carefully consider the risks described below, together with all of the other information included in this annual report, befor…
A. [Reserved] B. Capitalization and Indebtedness Not applicable. C. Reasons for the Offer and Use of Proceeds Not applicable. D. Risk Factors You should carefully consider the risks described below, together with all of the other information included in this annual report, before making an investment decision. Our business, financial condition and results of operations could be materially and adversely affected by any of these risks or uncertainties. In that case, the trading prices of our securities could decline, and you may lose all or part of your investment. The risks described below are those that we currently believe may materially affect us. Additional risks not presently known to us, or that we currently consider immaterial, may also materially adversely affect us. For purposes of this section, when we state that a risk, uncertainty or problem may, could or will have an “adverse effect” on us or “adversely affect” us, we mean that the risk, uncertainty or problem could have an adverse effect on our business, financial condition, results of operations, cash flow and/or prospects, except as otherwise indicated. You should view similar expressions in this section as having similar meaning. Summary of Risk Factors This section is intended to be a summary of more detailed discussions contained elsewhere in this annual report. The risks described below are not the only ones we face. Our business, results of operations or financial condition could be harmed if any of these risks materialize. Risks Relating to Brazil • Ongoing political instability has adversely affected the Brazilian economy and may lead to an economic slowdown, which may have an adverse effect on our financial condition and results of operations. • The Brazilian government has exerted and continues to exert significant influence over the Brazilian economy. This influence, as well as Brazilian political and economic conditions, may adversely affect the Company and the market price of our common shares and ADSs. • Changes in Brazilian tax laws or conflicts in their interpretation may adversely affect us and may have an adverse impact on the taxes applicable to a disposition of our shares or ADSs. • Inflation and the Brazilian government’s measures to combat it may contribute to economic uncertainty in Brazil, adversely affecting us and the market price of our common shares or ADSs. 1 Table of Contents • Exchange rate instability may adversely affect us, our foreign currency denominated debt and the market price of our common shares or ADSs and our ability to service our foreign currency denominated obligations. • Downgrades in Brazil's credit rating could adversely affect our credit rating, the cost of our indebtedness and the trading price of our common shares and ADSs. • Events, geopolitical tension and the perception of risks in other countries, especially the United States and emerging economies, may adversely affect the market price of Brazilian securities. Risks Relating to Our Business • Risks associated with the transfer of revenue and tariff adjustments related to the provision of water and sewage services to the city of São Paulo. • Any failure to obtain new funding or to comply with covenants in our existing financing agreements may adversely affect our ability to continue our capital expenditure program. • Any substantial monetary judgment against us or any of our directors and officers in legal proceedings may have a material adverse effect on our reputation, business or operating or financial condition and/or results. • We are subject to anti-corruption, anti-bribery, anti-money laundering, sanctions and antitrust laws and regulations. Our violation of any such laws or regulations could have a material adverse effect on our reputation, our results of operations and our financial condition. • Our business is subject to cyberattacks and security and privacy breaches. • Failure to comply with the LGPD or any further privacy and data protection laws enacted in Brazil could adversely affect our reputation, business, financial condition or results of operations. • Our failure to protect our intellectual property rights may negatively impact us. • Industrial accidents, equipment failure, environmental hazards or other natural phenomena may adversely affect our operations, assets and reputation and might not be covered by our insurance policies. • Our insurance policies may not cover or may be insufficient to cover claims which may arise. • We cannot guarantee that our suppliers and/or outsourced service providers will not engage in any irregular practices. • Our financial and operating performance may be adversely affected by epidemics, natural disasters and other catastrophes. • If we are not successful in addressing issues related to occupational health and safety for our employees and the facilities where we conduct our activities, our results and operations may be negatively affected. • If any of our assets are deemed assets dedicated to providing an essential public service, they will not be available for liquidation and will not be subject to attachment to secure a judgment. • Strikes, work stoppages or labor unrest by our employees or by the employees of our suppliers or contractors could adversely affect our business. • We are subject to obligations regarding respect for the human rights of all of our stakeholders, which may result in additional costs and significant contingencies. • If we do not remedy the material weakness in our internal controls, the reliability of our financial statements could be materially affected. 2 Table of Contents • Transactions with related parties, including as part of our privatization, may not have comparable market terms available and may not be entered into on an arm's length basis, which could expose us to lawsuits and affect our financial results. Risks Relating to Suppliers • Any interruptions in the supply of electricity and water may adversely affect our operations. • Our business is subject to risks arising from reliance on services and products from third-party suppliers. Risks Relating to Our Clients • We are owed some substantial unpaid debts. We cannot assure you as to when or whether we will be paid. Risks Relating to Our Management • We depend on the technical qualifications of the members of our management and certain key employees, and we cannot guarantee that we will be able to retain them or replace them with equally qualified individuals. Risks Relating to the Regulatory Environment • Regulatory conditions for access to federal funding and financing pose risks to our ability to obtain resources necessary for our operations and investments. • Pursuant to the New Legal Framework for Basic Sanitation, ANA will be responsible for issuing reference standards. Any non-compliance will prevent municipalities or operators from accessing financings and public resources managed or operated by the Brazilian government. • We are exposed to risks associated with the Concession Agreement for URAE-1, which may materially impact our financial condition and operating results. • If we do not meet the targets established by the Concession Agreement for URAE-1, our tariff adjustments might be reduced, which could materially adversely affect our business, financial condition, or results of operations. • The granting/contracting authorities may terminate contracts before they expire in certain circumstances. The indemnification payments we receive in such cases may be less than the value of the investments we made, or may be paid over an extended period, adversely affecting our business, financial condition, or results of operations. • If the water from our water sources (mananciais) does not meet our water treatment conditions, we may have to interrupt the water treatment process until we are able to treat the water or to substitute the supply of water from another water source. • Risks associated with the collection, treatment and disposal of wastewater and the operation of water utilities may impose significant costs that may not be covered by insurance, which could result in increased insurance premiums. • We are exposed to risks of delays or failures in payments associated with the provision of water and sewage services. • Securing new concessions, new public-private partnerships and new acquisitions involve risks related to the integrations of the adjudicated or acquired businesses, the situation of the assets and the regularity of the operations related to the concessions. • Our expansion strategy includes acquisitions that involve significant risks and uncertainties, which could adversely affect our business, results of operations, and financial condition. 3 Table of Contents • Risks related to encumbrances, which may negatively affect us in the event of default on the obligations guaranteed by our properties. • If we are unable to obtain or renew environmental permits and/or licenses, we may be subject to fines and the closure of any irregular facilities, with the interruption of activities carried out by us at such facilities. • According to the Brazilian law regulating concessions and public-private partnership matters, our corporate structure is composed of some special purpose entities, which may result in our responsibility for tax, labor, environmental protection, consumer and bankruptcy matters originated from our subsidiaries. • We are subject to penalties related to our registrations, authorizations, licenses and permits for the development of our activities. Risks Relating to Environmental Matters and Physical and Climate Transition Risks • Noncompliance with environmental laws and environmental liability could have a material adverse effect on us and our reputation. • Environmental, social and governance considerations could expose us to potential liabilities, increased costs (regulatory or otherwise), compliance failures and reputational harm, including with respect to the B3 Green Shares classification we have been granted. • Droughts, such as the 2014 – 2015 water crisis, can cause a material impact on consumption habits and, consequently, on our business, financial condition or results of operations. • Extreme weather conditions and climate change may have a material adverse impact on our business, financial condition or results of operations. • New laws and regulations relating to climate change and changes in existing regulation may result in increased liabilities and increased capital expenditures, which could have a material adverse effect on us. Risks Relating to Our Privatization • Our Privatization may still be subject to legal challenge, and the dispersed ownership structure resulting from our Privatization may impact our ability to efficiently approve certain transactions and could potentially delay critical decision-making processes, which may adversely affect our business and results of operations Risks Relating to Our Common Shares and ADSs • We may issue additional common shares or enter into a merger, consolidation or other similar corporate transaction, which could dilute your interest in our common shares underlying the ADS. • International judgments may not be enforceable when considering our directors or officers’ status of residency. • We may not always be in a position to pay dividends or interest on shareholders’ equity and ADSs. • Mandatory arbitration provisions in our bylaws may limit the ability of a holder of our ADRs to enforce liability under U.S. securities laws. • A holder of our common shares and ADSs might be unable to exercise preemptive rights and tag-along rights with respect to the common shares. • Holders of our ADSs do not have the same voting rights as our shareholders. • Judgments of Brazilian courts with respect to our common shares are required to be payable only in reais. 4 Table of Contents Risks Relating to Brazil Ongoing political instability has adversely affected the Brazilian economy and may lead to an economic slowdown, which may have an adverse effect on our financial condition and results of operations. Brazil has experienced amplified economic and political instability, as well as heightened volatility, as a result of several investigations by national and foreign agencies responsible for corruption and cartel investigations. Investigations into allegations, trials and convictions of Brazilian government and State of São Paulo government officials and senior management of Brazilian companies may lead to further allegations and charges, which in turn may lead to political instability and a decline in confidence by consumers and foreign direct investors in the stability and transparency of the Brazilian government and Brazilian companies. This may have a material adverse effect on Brazil’s economic growth, the demand for securities issued by Brazilian companies, and access to the international financial markets by Brazilian companies. Furthermore, the President has the power to impose policies and issue governmental acts (Medidas Provisórias) regarding the Brazilian economy that may affect our operations and financial performance. We cannot predict what policies the President will impose, much less whether such new policies or changes in current policies will have an adverse effect on our business or the Brazilian economy. Additionally, the Brazilian government’s potential difficulty in securing a majority in the National Congress could obstruct policy implementation, further contributing to economic instability. These uncertainties, along with any new measures that may be implemented, may increase the volatility of the Brazilian securities market. Historically, political crises have affected investor confidence as well as public opinion, and any of the above factors may create additional political uncertainty, which could harm the Brazilian economy and, consequently, our business, results of operations, financial condition and the trading price of our common shares and ADSs. The Brazilian government has exerted and continues to exert significant influence over the Brazilian economy. This influence, as well as Brazilian political and economic conditions, may adversely affect the Company and the market price of our common shares and ADSs. The Brazilian government frequently intervenes in the Brazilian economy and occasionally makes significant changes in policy and regulations. The Brazilian government’s actions to control inflation and other policies and regulations have often involved, among other measures, changes in interest rates, tax policies, price and tariff controls, foreign exchange rate controls, currency devaluation or appreciation, capital controls and limits on imports and exports. Our business, financial condition and results of operations, as well as the market price of our common shares or ADSs, may be adversely affected by changes in public policy at federal, state and municipal levels with respect to public tariffs and exchange controls, as well as other factors, such as: • expansion or retraction of the Brazilian economy; • the regulatory environment and changes in laws and regulations; • interest rates fluctuations, inflation and foreign exchange rate movements; • availability of credit and liquidity of the Brazilian capital and lending markets; • commodity prices; • import and export controls; • public debt; • economic, political and social instability; • water and electricity shortages and rationing; • other factors identified or discussed under “Risk Factors”. 5 Table of Contents We cannot predict the measures that the Brazilian government will take due to mounting macroeconomic pressures or otherwise. Economic and political instability and uncertainty has led to a negative perception of the Brazilian economy and higher volatility in the Brazilian capital markets and the securities of Brazilian issuers, which may adversely affect our activities, results of operations, and the trading price of our common shares and ADSs. For more information, see “Item 3.D. Risk Factors—Risks Relating to Brazil—Ongoing political instability has adversely affected the Brazilian economy and may lead to an economic slowdown, which may have an adverse effect on our financial condition and results of operations.” Changes in Brazilian tax laws or conflicts in their interpretation may adversely affect us and may have an adverse impact on the taxes applicable to a disposition of our shares or ADSs. The Brazilian government frequently modifies tax laws, including tax treaties, rates, and benefits, which may increase our tax liabilities and adversely affect our profitability and results of operations. In addition, tax authorities may interpret laws in a way that differs from the interpretation we currently rely upon to carry out our transactions, potentially leading to adverse financial effects. We cannot assure that we will be able to maintain our projected cash flows and profitability following any increases in Brazilian taxes applicable to our operations, which may adversely affect our results of operations and financial condition. Brazil is undergoing significant tax reform, particularly on the taxation of goods and services. On December 20, 2023, Constitutional Amendment No. 132/2023 (“EC 132”) was enacted, replacing several of the current “indirect taxes” (ICMS, IPI, ISS and PIS/COFINS) by three new ones: a Goods and Services Tax (IBS), a Contribution on Goods and Services (CBS) and an Excise Tax (IS). The transition period runs from 2026 to 2032, with full implementation by 2033. The regulatory process for EC 132 through legislation (complementary and ordinary laws) is underway. On January 16, 2025, Complementary Law No. 214/2025 was enacted, establishing the general legal framework applicable to IBS, CBS and IS. It is expected that the standard rate for the sum of IBS and CBS to be generally levied on any type of services and goods (with some limited exceptions) will be 28.0%. Further reforms on income and payroll taxation are also under discussion by the Brazilian government. EC 132 provides that the executive branch must submit to the National Congress, within 90 days of its enactment, bills of law for reforming income and payroll taxation. As of the date of this annual report, no such bills have been submitted. Several bills aimed at reforming the Brazilian Income Tax system have been submitted to Congress. In November 2025, the enactment of Law No. 15,270/2025 introduced changes such as a minimum annual taxation for high-income individuals, an increase in the personal income tax exemption threshold, and a 10% withholding income tax on certain dividend distributions to individuals and remittances abroad. Subsequently, Complementary Law No. 224/2025 established a 10% linear reduction of federal tax incentives and benefits granted to companies established in Brazil in relation to certain federal taxes, and increased the withholding tax on Interest on Net Equity (Juros sobre Capital Próprio) from 15% to 17.5% starting in 2026. In addition, Law No. 10,833/2003 provides that the disposition of assets located in Brazil by a non-resident to either a Brazilian resident or a non-resident is subject to taxation in Brazil, regardless of whether the disposition occurs outside or within Brazil. This provision results in the imposition of withholding income tax on gains arising from a disposition of our common shares by a non-resident of Brazil to another non-resident of Brazil. There is no judicial guidance as to the application of Law No. 10,833/2003 to dispositions of ADSs, and accordingly, we are unable to predict whether Brazilian courts may decide that it applies to dispositions of our ADSs between non-residents of Brazil. However, in the event that the disposition of assets is interpreted to include a disposition of our ADSs, this tax law would result in the imposition of withholding taxes on the disposition of our ADSs by a non-resident of Brazil to another non-resident of Brazil. For purposes of Brazilian taxation, the income tax rules on gains related to the disposition of common shares or ADSs can vary depending on the domicile of the non-Brazilian holder and the form by which the non-Brazilian holder has registered its investment. We cannot predict the effects of changes in Brazilian tax laws, and if they may have an adverse effect on our business, financial condition or results of operations. 6 Table of Contents Inflation and the Brazilian government’s measures to combat it may contribute to economic uncertainty in Brazil, adversely affecting us and the market price of our common shares or ADSs. Brazil has historically experienced high rates of inflation, and the Brazilian government’s measures to control inflation have had, and may continue to have, significant effects on the Brazilian economy and on our business, financial condition and results of operations. Monetary tightening cycles, characterized by high interest rates, may constrain economic growth, reduce credit availability and increase our cost of funding. Conversely, other Brazilian governmental actions, including reductions in interest rates, intervention in the foreign exchange market, or measures intended to influence the value of the real, may trigger increases in inflation expectations. Brazil’s General Price Index (Índice Geral de Preços – Mercado), or IGP-M index, recorded deflation of 1.05% in 2025, inflation of 6.54% in 2024 and deflation of 3.18% in 2023. Brazil’s National Broad Consumer Price Index (Índice Nacional de Preços ao Consumidor Amplo), or IPCA index, recorded inflation of 4.26% in 2025, 4.83% in 2024 and 4.62% in 2023. In Brazil, the Central Bank’s Monetary Policy Committee, or COPOM, is responsible for setting the Brazilian official interest rate, or the Selic rate. COPOM frequently adjusts the official base interest rates to meet the economic goals established by the Brazilian government´s National Monetary Council, particularly the inflation-targeting regime. In the event of an increase in inflation, the COPOM may choose to significantly increase interest rates. For example, as of December 31, 2023 and 2024, the Selic rate was 11.75% and 12.15% per annum, respectively. In 2025, the Selic rate further increased, reaching 15.00% in June 2025, its highest level since 2006. In 2026, the Selic rate eased slightly, declining to 14.75% per annum as of the date of this annual report. If Brazil once again experiences substantial high inflation or deflation in the future, our business, financial condition or results of operations may be adversely affected, including our ability to comply with our obligations. In addition, a significant increase in inflation may weaken investor confidence in Brazil, adversely affecting the market price of our common shares or ADSs. Exchange rate instability may adversely affect us, our foreign currency denominated debt and the market price of our common shares or ADSs and our ability to service our foreign currency denominated obligations. As a result of inflationary pressures, the Brazilian currency has, at times, depreciated against the US dollar and other foreign currencies. The devaluation of the Brazilian real against major foreign currencies, including the US dollar, may create additional inflationary pressure in Brazil, potentially leading the Brazilian Central Bank (Banco Central do Brasil), or Bacen, to raise interest rates in an effort to stabilize the economy. Depending on the circumstances, these measures may affect the overall growth of the Brazilian economy and, in some cases, may adversely impact our financial condition and results of operations. Foreign exchange rate fluctuations will impact the U.S. dollar value of our common shares on the B3, as well as the U.S. dollar equivalent of any distributions we make in reais with respect to our common shares. In addition, because we have debt denominated in foreign currencies, any significant devaluation of the real will increase our financial expenses as a result of foreign exchange losses that we must record. This would also increase our total debt, which could lead us to breach any debt/EBITDA covenants we are subject to in certain financings. We had total foreign currency denominated debt of R$10.6 billion as of December 31, 2025, and we anticipate that we may incur additional amounts of foreign currency denominated debt in the future. In December 2023, our Board of Directors approved our hedging policy, and in 2024 and 2025, we entered into derivative instruments to hedge against a depreciation of the real against the U.S. dollar. We cannot guarantee we will always be able to enter into derivative instruments to hedge in favorable terms. A devaluation of the real may adversely affect us and the market price of our common shares or ADSs. For more information, see Note 5.1(a) to our 2025 Consolidated Financial Statements. 7 Table of Contents Downgrades in Brazil’s credit rating could adversely affect our credit rating, the cost of our indebtedness and the trading price of our common shares and ADSs. Brazil has experienced the loss of investment grade status from credit rating agencies such as Standard & Poor’s, Moody’s, and Fitch Ratings, as well as a downgrade by Standard & Poor’s. As a result, any changes in Brazilian government policies or fluctuations in Brazil’s sovereign credit rating—factors beyond our control—may contribute to increased volatility in the Brazilian capital markets and have a material adverse effect on us and the market price of our common shares and ADSs. Recently, the Brazilian political and economic environment has experienced high levels of volatility and instability, including contraction of GDP, sharp fluctuations in the real against the US dollar, rising unemployment, and lower consumer spending and confidence. We cannot predict the potential impacts of policies to be adopted by the Federal Government. The most recent change by Fitch, on June 25, 2025, upgraded Brazil’s sovereign credit rating to BB with a stable outlook, citing better-than-expected macroeconomic and fiscal performance despite successive shocks in recent years. As of the date of this annual report, Brazil’s credit rating was BB (Standard & Poor’s), Ba1 (Moody’s), and BB with a stable outlook (Fitch). If there are further downgrades in Brazil’s credit rating by rating agencies, investor risk perception may increase and, as a result, the trading value of our securities may decrease, which could negatively impact our shareholders and holders of our securities. Events, geopolitical tension and the perception of risks in other countries, especially the United States and emerging economies, may adversely affect the market price of Brazilian securities. International investors generally consider Brazil an emerging market. Historically, adverse events in emerging economies have resulted in a perception of greater risk by global investors, including those from the United States and Europe. Such perceptions regarding emerging market countries significantly affect Brazil, the Brazilian capital market, and the availability of credit in Brazil, both from domestic and international sources. Additionally, the Brazilian economy and the market price of securities of Brazilian companies are influenced, to varying degrees, by economic and market conditions in Brazil and other countries, including the United States, Europe, and other emerging economies. Even if economic conditions in these countries differ significantly from those in Brazil, investor reactions to events in other countries may have a material adverse effect on the Brazilian economy and the market value of securities issued by Brazilian issuers. In the past, the development of adverse economic conditions in other countries has generally resulted in capital outflows and, consequently, a reduction in external resources invested in Brazil. Any of the above events may adversely affect the market value of our securities and make it more difficult for us to access the capital markets and finance our operations in the future, on acceptable terms or at all. Brazil is subject to events such as: (i) political instability in the United States; (ii) the conflict between Ukraine and Russia, which triggered a military and geopolitical crisis with worldwide repercussions; (iii) the trade war between the United States and China; (iv) the conflict in the Gaza Strip and tensions in the Middle East, including the escalation of hostilities involving the United States and Israel; (v) crises and tensions between Venezuela and the United States; and (vi) crises in Europe and other countries that affect the global economy, producing or potentially producing a series of effects that directly or indirectly affect the capital markets and the Brazilian economy, including fluctuations in the prices of listed companies' securities, reduced credit availability, deterioration of the global economy, exchange rate and inflation fluctuations, negative impacts on the supply chain for raw materials, and increased inflation and interest rates on goods, among others, which may have a material adverse effect on our financial condition and results of operations. The U.S. government has been implementing protectionist policies, including imposing tariffs on a range of products from various countries, such as China, the European Union, and Brazil. Among other measures, the U.S. government recently announced a 50% tariff on Brazilian imports, including manufactured goods, commodities, and agricultural products, which entered into force, subject to exceptions, on August 1, 2025. In addition, the United States maintains extraterritorial international sanctions programs, such as the Global Magnitsky Human Rights Accountability Act, which have been applied to certain Brazilian individuals. These measures have contributed to increased geopolitical tensions, greater market volatility, and increased uncertainty regarding international trade and capital flows, potentially resulting in a slowdown in global trade and economic activity. Changes in U.S. government policies may significantly and adversely affect the Brazilian economy and, consequently, the market value of our securities. 8 Table of Contents In February 2026, the United States and Israel launched coordinated military strikes against key Iranian military and infrastructure targets. This marked a significant escalation of hostilities, resulting in heightened instability across the Middle East, further disruptions to global energy markets, and increased volatility in international trade and supply chains. Escalation or expansion of hostilities, interventions by other groups or nations, the imposition of economic sanctions, disruption of shipping transit in the Straits of Hormuz or other significant trade routes, or similar outcomes could adversely affect global international trade and financial markets, which could in turn have a material adverse effect on the Brazilian economy and the market value of our securities. For example, the conflict involving the Russian Federation and Ukraine poses a risk of further increases in fuel and gas prices; occurring simultaneously with a possible appreciation of the U.S. dollar, these increases would exert even more inflationary pressure and could hinder Brazil's economic recovery. Additionally, the conflict impacts the global supply of agricultural commodities, so that, if grain prices rise due to increased demand, demand for Brazilian production would increase, given Brazil’s high production capacity and ability to negotiate more competitive prices; thus, export rates and domestic prices would rise, generating further inflationary pressure. Furthermore, a significant portion of Brazilian agribusiness is highly dependent on fertilizers imported from the Russian Federation and its allies (the Republic of Belarus and the People's Republic of China). Changes in the export policy of these products could adversely affect the economy and, consequently, the capital market. It is important to note that, following the Russian invasion on February 24, 2022, animosities have arisen not only among the directly involved countries but also in many other nations indirectly interested in the issue, creating a scenario of high uncertainty for the global economy. Additionally, the Brazilian economy is affected by market conditions, including commodity market conditions (particularly iron ore, oil, coffee, corn, soybeans, and live cattle), as well as by international economic conditions, especially those of the United States. The prices of shares and other securities traded on B3, for example, are highly affected by fluctuations in U.S. interest rates and the performance of major U.S. stock exchanges. Any increase in interest rates in other countries, especially the United States, may reduce global liquidity and investor interest in investing in the Brazilian capital market, which could have a material adverse effect on the market price of our securities. Risks Relating to Our Business Risks associated with the transfer of revenue and tariff adjustments related to the provision of water and sewage services to the city of São Paulo. The provision of water and sewage services in the city of São Paulo accounted for 45.7% of our gross operating revenue from sanitation services (excluding revenues relating to the construction of concession infrastructure) in the year ended December 31, 2025. On June 23, 2010, the State and the city of São Paulo executed a convention agreement (convênio) with our intermediation and ARSESP’s consent, under which they agreed to manage the planning and investment for the basic sanitation system of the city of São Paulo on a joint basis. We executed a service contract with the State and the city of São Paulo on the same date to provide these services for the next 30 years, pursuant to which, among other things, we must transfer 7.5% of the gross revenues we obtain from this contract, less COFINS and PASEP taxes, and unpaid bills for services provided to properties owned by the city of São Paulo, to the FMSAI, as per Municipal Law No. 14,934/2009. For more information, see “Item 7.B. Related Party Transactions” for a further discussion of the principal terms of this convention and the service contract we executed in accordance with this convention. As a result of the second ordinary tariff revision, published in ARSESP Resolution No. 794/2018 (“Second Ordinary Tariff Revision”), ARSESP allows the pass-through of up to 4% of the municipal revenue we transfer to a legally established municipal infrastructure fund. ARSESP Resolution No. 1545/2024 subsequently established the criteria and conditions to permit the transfer of 4% of such revenue from service providers. In addition, for recognition as part of the tariff, municipal funds for environmental sanitation and infrastructure must be established by the municipality through a legal act, which specifies the allocation of resources. For the fourth tariff cycle (2021-2024) ARSESP has set a 4% cap on transfers to municipal funds, with these transfers requiring prior approval by ARSESP and formal recognition as part of the tariff structure. 9 Table of Contents Considering that ARSESP limited the transfer of tariffs for amounts transferred to municipal infrastructure funds to 4%, the mandatory contractual transfer of the remaining 3.5% of gross revenue (excluding COFINS and PASEP taxes and unpaid bills of public properties in the city of São Paulo) to FMSAI was not fully transferred to customers until the effective date of the current concession agreement signed with URAE 1. From 2010 to December 31, 2023, we transferred approximately R$5.9 billion to FMSAI. For additional information on ARSESP regulations, see “Item 4.B. Business Overview—Government Regulations Applicable to Our Contracts—ARSESP.” On July 13, 2021, the city of São Paulo filed a public civil action against us, the State of São Paulo and ARSESP, aiming, in general terms, to discuss the possibility of including the charge to FMSAI in the tariff adjustment provided for in Resolution No. 870/2019, which in practice was already being transferred pursuant to Resolution No. 794/2018. In summary, this public civil action seeks: (i) the recognition of illegality of the transfer of 7.5% of our gross revenue, related to FMSAI, to the water and sewage tariff applicable in the city of São Paulo; (ii) to establish our liability for any damages caused to users affected by ARSESP Resolutions 794/2018 and 870/2019; and (iii) the recognition of the inexistence of liabilities to be paid to us for the transfers to FMSAI made by it since 2010, since they would already be included in the tariff value from the beginning. On August 19, 2021, the city of São Paulo requested the suspension of the process in view of the ongoing negotiations in search of an amicable solution to the dispute. On September 13, 2021, the suspension of the case for a period of 90 days was granted. On August 15, 2022, the city of São Paulo reported that the settlement negotiations were still ongoing. On February 12, 2025, the city of São Paulo requested an additional suspension of the process for 30 days, and, as of the date of this annual report, there have been no further developments. We have not yet been appointed and we cannot predict the outcome of this process, which, if unfavorable, could have a negative economic impact on us. The Concession Agreement for URAE-1 provides for the full recognition of tariff payments to FMSAI for the municipality of São Paulo (as of the effective date of the new concession contract), which means that the rate of 7.5% is now recognized in the tariffs. Please see “Presentation of Financial and Other Information—Privatization” for more information on contributions to this public consultation, and “Item 4.B. Business Overview” for more information on our tariff structure. Any failure to obtain new funding or to comply with covenants in our existing financing agreements may adversely affect our ability to continue our capital expenditure program. At the time of our privatization, the capital expenditure program to meet our coverage and service targets was estimated to be R$70 billion between 2024 and 2029. For the year ended December 31, 2025, we recorded R$15.2 billion in capital expenditures. We intend to continue funding these capital expenditures with cash generated by our operations, issuances of debt securities in the domestic and international capital markets as well as borrowings in Brazilian reais and foreign currencies. A significant portion of our financing needs is obtained through long-term financing at attractive interest rates from Brazilian federal public banks, multilateral agencies and international governmental development banks. If the Brazilian government changes its policies regarding public financing or amounts available for water and sewage services, or if we fail to obtain long-term financing at attractive interest rates in the future, we may not be able to meet our obligations or finance our capital expenditure program, which could have a material adverse effect on our business, financial condition or results of operations. Our debt includes financial covenants that impose indebtedness limits, as well as several non-financial covenants, including the pledging of assets, provision of financial statements and audit reports, change of control provisions and compliance with environmental laws and licenses, among others. Our failure to comply with any of these covenants could seriously impair our ability to finance our capital expenditure program, which could have a material adverse effect on us. For more information on these covenants, see “Item 5.B. Liquidity and Capital Resources—Indebtedness Financing-Financial Covenants.” 10 Table of Contents Any substantial monetary judgment against us or any of our directors and officers in legal proceedings may have a material adverse effect on our reputation, business or operating or financial condition and/or results. We are and may in the future be party to legal proceedings related to civil, corporate, environmental, labor, tax, and/or criminal actions filed against us, which may require us to expend substantial funds and other resources. These claims involve substantial amounts of money and other remedies. As of December 31, 2025, the total estimated amount of claims related to our legal proceedings was R$18.2 billion (net of court deposits). Of this amount, R$1.9 billion was provisioned, representing only claims assessed as involving probable losses. This provision does not include exposures classified as possible or remote losses. Our provisions do not cover all legal proceedings involving monetary claims filed against us and may be insufficient to cover any amounts arising from unfavorable final decisions, which may have a material adverse effect on our financial condition and reputation. Further, one or more of our directors and officers may become parties to civil, administrative, environmental, criminal or tax judicial, administrative or arbitration proceedings, of which the initiation and/or outcome may adversely affect them and impair their ability to perform their duties with us, which could lead to a material adverse effect on our reputation, business or operating or financial condition and/or results. Unfavorable judicial, administrative, and arbitral decisions against us, our subsidiaries, executives, and directors, particularly those involving substantial amounts or preventing us from conducting business as initially planned, may adversely affect our results, business, reputation, financial situation, and market value of our shares and ADSs. Negative decisions involving criminal proceedings, especially those related to corruption or administrative misconduct, could also impact our executives’ ability to perform their duties or restrict our ability to contract with the government and access tax benefits and significantly harm our reputation and business. Furthermore, the Public Prosecutor’s Office and environmental agencies may initiate administrative procedures to investigate possible environmental damages caused by our activities, which may lead to recommendations, “conduct adjustment agreements” and/or general “terms of commitments” with the relevant authorities, assuming specific obligations for a determined period. Non-compliance with these terms could result in fines, enforcement, and filing of lawsuits. Finally, parliamentary inquiry commissions and regulatory and oversight bodies, such as the State Audit Court (Tribunal de Contas do Estado de São Paulo - TCE), the National Water and Sanitation Agency (Agência Nacional de Águas e Saneamento Básico - ANA) and ARSESP, may scrutinize our operations, processes, contracts, procedures, and partnerships. Investigations or unfavorable decisions may (i) restrict our ability to conduct our business; (ii) require us to make payments that have not been provisioned for; (iii) affect the continuity or profitability of our service lines; (iv) prevent or delay the execution of our projects as initially planned;; and (v) prohibit us from entering into contracts with the public administration to receive fiscal incentives and benefits and access financing and resources. Furthermore, such bodies may initiate processes including judicial, administrative and arbitral proceedings, which may lead to unfavorable decisions and adversely affect our business, financial situation, and reputation. For more information, see “Item 8.A. Consolidated Financial Statements and Other Financial Information—Legal Proceedings” and Note 23 to our 2025 Consolidated Financial Statements included in this annual report. We are subject to anti-corruption, anti-bribery, anti-money laundering, sanctions and antitrust laws and regulations. Our violation of any such laws or regulations could have a material adverse effect on our reputation, our results of operations and our financial condition. We are subject to anti-corruption, anti-bribery, anti-money laundering, sanctions, antitrust and other similar laws and regulations. We are required to comply with the applicable laws and regulations of Brazil and the U.S. Foreign Corrupt Practices Act (“FCPA”), and we may become subject to similar laws and regulations in other jurisdictions. The existence of any investigation, inquiry or proceeding of an administrative or judicial nature related to the violation of any of these laws or regulations, in Brazil or abroad, for acts against the public administration by our affiliates or subsidiaries, managers, employees or any third parties acting on our behalf, may result in the application of sanctions, which may include (i) administrative, civil or criminal fines and indemnities (the latter applicable to the members of management who participated in the infraction); (ii) an obligation to repair the damage caused; (iii) extraordinary publication of the conviction; (iv) inclusion in the National Register of Punished Companies (CNEP); (v) a criminal conviction; (vi) forfeiture of the benefits or assets illicitly obtained; (vii) partial or full suspension of activities; (viii) a prohibition on entering into contracts with the government or receiving tax or credit benefits or incentives; and (ix) compulsory dissolution or disregard of the company’s personality There can be no assurance that our internal policies and procedures will be sufficient to prevent, detect and timely implement corrective measures in relation to any unlawful and inappropriate practices, fraud or violations by our employees, officers, executives, partners, agents and service providers and other third parties, nor that any such persons will not take actions in violation of our policies and procedures. 11 Table of Contents From time to time, we receive or become aware of complaints or allegations of potential breaches of applicable anti-corruption, anti-bribery or other laws and regulations or our internal policies and procedures (including our procurement processes) through our whistleblower channel or other internal or external sources. Our internal audit team processes these complaints or allegations, and our audit committee may engage outside counsel to investigate given the nature of the complaints or allegations. The findings of our internal audit team and any outside counsel are reported to our audit committee. These complaints or allegations under the supervision of our audit committee may lead to formal government inquiries or investigations and harm to our reputation. If we or any of our subsidiaries, directors, officers, employees, partners, agents, service providers or other persons are deemed or perceived to have engaged in activities violative of applicable laws, regulations or internal controls or procedures, we could become subject to government enforcement actions, penalties, damages, fines and sanctions, as well as events of default or prepayment events under our outstanding indebtedness, that could result in a material adverse effect on our reputation, business, our ability to obtain financing for our business, our financial condition, our results of operations and the market price of our common shares and ADSs. Our business is subject to cyberattacks and security and privacy breaches. Our business depends on the availability, integrity and security of information technology ("IT") and operational technology ("OT") systems to support water supply, sewage collection and treatment, and commercial, administrative and financial operations. We also collect, store, process and transmit personal or sensitive and operational data relating to customers, suppliers and employees. As a result, we are subject to risks associated with cybersecurity incidents, including unauthorized access, data breaches, malware, ransomware, system intrusions, human error, system failures and third-party security incidents. Cybersecurity threats continue to evolve and may increase in frequency, scale and sophistication, including threats from well-resourced and highly capable actors. Attack methods may involve exploitation of system vulnerabilities, social engineering techniques or compromises affecting vendors, service providers or other third parties. Any actual or perceived cybersecurity incident could result in operational disruptions, data loss or unauthorized disclosure of information, impairment of critical systems, reputational harm, regulatory investigations, litigation or financial losses, and could adversely affect our business, financial condition or results of operations. On October 16, 2024, we experienced a cyberattack that caused disruptions to our digital network, resulting in the unavailability of certain systems and the exfiltration and publication of certain data. We notified the Brazilian National Data Protection Agency (Agência Nacional de Proteção de Dados – “ANPD”) in accordance with applicable law and in 2025, the matter was formally closed by such authority in light of the remedial measures adopted and our cooperative conduct, with no material harm identified to data subjects. We cannot assure you that the measures we have implemented in response to this incident will be sufficient to prevent future incidents of a similar or greater magnitude, or that we will not face regulatory scrutiny, litigation, reputational harm or other adverse consequences arising from this or any future cybersecurity incident. We may be subject to additional information security incidents or data breaches in the future. There can be no assurance that our cybersecurity and other technical and organizational measures will be effective against all threats, particularly as attack techniques continue to evolve. A significant cybersecurity incident could adversely affect our operations, financial condition, results of operations and reputation. For more information, see “Item 16.K. Cybersecurity.” 12 Table of Contents Failure to comply with the LGPD or any further privacy and data protection laws enacted in Brazil could adversely affect our reputation, business, financial condition or results of operations. We are subject to privacy and personal and data protection laws, including the Brazilian Federal Constitution, the Brazilian Consumer Protection Code (Law No. 8,078/1990) (the “Consumer Protection Code”), Law No. 12,965/2014 (the “Brazilian Internet Civil Rights Framework” – Marco Civil da Internet) and Law No. 13,709/2018 (the “Brazilian General Data Protection Law” or “LGPD”), as well as related regulations, including those issued by the ANPD. The LGPD establishes rules governing the collection, use, processing, sharing, storage, retention, disposal, and all other forms of processing of personal data, applicable to all economic sectors, both in digital and physical environments. The ANPD is responsible for overseeing compliance with the LGPD, including issuing regulations, conducting investigations, and imposing administrative sanctions. Failure to comply with the LGPD — particularly with respect to ensuring data subjects’ rights, implementing adequate documentation and data governance programs, providing clear and transparent information regarding our personal data processing activities, ensuring that data processing is limited to its stated purposes, complying with legally mandated data retention periods, and implementing the required security standards—may subject us to administrative sanctions. Such sanctions may include warnings, public disclosure of violations, temporary blocking or deletion of personal data, suspension or prohibition of data processing activities, daily fines, and fines of up to 2% of the Company’s, group’s, or conglomerate’s gross revenue in Brazil in the prior fiscal year, net of taxes, capped at R$50 million per violation. In addition to the administrative sanctions that could be imposed by the ANPD , violations of the LGPD laws and regulations relating to privacy and protection of personal data may result in judicial proceedings, enforcement actions by other authorities, such as the Public Prosecutor’s Office and consumer protection agencies, which may lead to penalties provided , adverse court decisions requiring the payment of compensation for under other applicable laws, including the Brazilian Consumer Protection Code (Law No. 8,078/1990) and the Brazilian Internet Civil Rights Framework damages , as well as reputational harm and damage to our brand and public image. We are also subject to legal actions brought directly by affected data subjects, which may result in the payment of damages. We cannot guarantee that our personal data processing activities will always be secure, compliant, and adequate, nor that we will not be subject to fines or other sanctions. The imposition of penalties or obligations to remedy failures in personal data protection or LGPD compliance may negatively affect our reputation, business operations, and, consequently, the value of our common shares and ADSs. In 2024, we experienced a cybersecurity incident, which we reported and notified to the ANPD in accordance with applicable law. In 2025, the matter was formally closed by the authority in light of the remedial measures adopted and our cooperative conduct, with no material harm identified to data subjects. Additionally, in 2025, we were sued by Instituto Sigilo for alleged violations of personal data protection laws,in Brazil, in which we obtained a favorable decision in the first instance. This legal proceeding is currently pending at the Brazilian appellate level court. We cannot assure you that the ANPD or other regulatory authorities will not initiate additional investigations or proceedings in connection with this procedure or any other incident, or as a consequence of it, nor can we exclude the possibility that any pending or future judicial or administrative proceedings will not may result in sanctions, penalties or other adverse consequences that could affect our business, financial condition, results of operations or reputation. Our failure to protect our intellectual property rights may negatively impact us. We own and license from third parties several intellectual property assets, including trademarks, patents, software, copyrights, and domain names. Therefore, we rely on intellectual property laws and registration authorities in Brazil and abroad, as well as on license agreements, to protect our intellectual property. 13 Table of Contents Events such as the rejection of patent applications or trademark registrations by the National Institute of Industrial Property (“INPI”), or the unauthorized use or other improper appropriation of our intellectual property assets, especially the “Sabesp” trademark and other trademarks used in our business, can diminish the value of our brands or affect our reputation. Furthermore, we cannot guarantee that the measures taken to protect our intellectual property rights are and will continue to be sufficient to protect us against potential illicit actions by third parties. Similarly, third parties may claim that our services, or even our intellectual property assets, violate their intellectual property rights. Any dispute or litigation,whether judicial or administrative, related to intellectual property assets, including, without limitation, any allegation of infringement arising from the products and/or services provided by us, even if it concerns assets of low relevance to our operations, can be costly and time-consuming and, as a result, may adversely affect our operations, our business and our operating results. Therefore, any situation that affects our protection with respect to our intellectual property assets may have adverse impacts on our business. Additionally, we have entered into temporary licensing agreements for the use of certain technologies essential to the development of our operations, such as software licensing agreements. If we are unable to renew or maintain the licenses for the necessary intellectual property rights, we may face difficulties in replacing these technologies. Furthermore, if this scenario occurs and we continue to use these technologies without the necessary licenses, the holders of these intellectual property rights may demand that we cease using such rights and seek compensatory damages. Furthermore, third parties may claim that the services we provide infringe their intellectual property rights. Any alleged violation or infringement of intellectual property rights against us may result in costly and time-consuming litigation and, consequently, adversely affect our operational results. If we are not successful in defending against potential claims or reaching settlements, we may be required to pay damages, cease the use of third-party intellectual property, or enter into licensing agreements on unfavorable terms. Industrial accidents, equipment failure, environmental hazards or other natural phenomena may adversely affect our operations, assets and reputation and might not be covered by our insurance policies. Currently, we substantially source our water supply from rivers and reservoirs, although we source a small portion from groundwater wells. Our reservoirs are filled with impounding water from rivers and streams, by diverting the flow from nearby rivers, or by a combination of both methods. As of December 31, 2025, we had 28 large-scale reservoirs which are classified under Brazilian dam safety legislation, which, due to their characteristics, may be associated with potential damages. Our operations may be hampered by numerous factors, including unexpected or unusual geological and/or geotechnical operating conditions, industrial accidents, floods and/or droughts or other environmental occurrences that could result in structural damages and eventually rupture of our dams and other facilities or equipment. Our water and sewage pipes are susceptible to degradation caused by factors such as aging, intense traffic, interventions resulting from disorderly urban planning and action by other companies, which may provoke accidents in the networks, increasing the risk of physical loss of water and leakage of sewage, which could affect the regular provision of our services, impacting our customers, the society and the environment. Regarding sanitary sewage, our sewage pipes may also be obstructed due to misuse resulting from the improper release of solid waste and rainwater in the sewage systems, which could also lead to the risks mentioned above. In particular, the increasing degradation of our water sources (mananciais) may affect the quantity and quality of water available to meet demand from our customers. For more information, see “Item 4.B. Business Overview—Description of Our Activities—Water Operations,” “Item 4.B. Business Overview—Description of Our Activities— Water Distribution” and “Item 4.B. Business Overview—Description of Our Activities—Sewage Operations—Sewage System.” The occurrence of any of these events could lead to personal injury or death, adverse social impacts on the communities located near our facilities, monetary losses and possible legal liability arising from environmental and social damages, other environmental and social damages, the loss of prime materials, substantial financial costs potentially not covered by insurance and damage to our reputation. For more information, see “Item 4.B. Business Overview—Description of Our Activities Water Operations—Water Resources.” 14 Table of Contents Our insurance policies may not cover or may be insufficient to cover claims which may arise. Due to the high premiums associated with insurance policies and other factors relating to our risk management, it is not always possible to obtain insurance against all types of risks and liabilities associated with our activities and related assets. We cannot guarantee that our existing insurance policies are adequate and sufficient for all circumstances that may arise or against all inherent risks and for amounts that cover all the losses we may occur. If a claim is not covered by our insurance policies, or if damages exceed the policy limits, we may incur additional costs for the repair or replacement of damaged assets or for compensation to third parties, which could adversely affect our results of operations and reputation. Furthermore, for insured events, coverage is contingent upon the payment of a premium and the fulfillment of specific obligations stipulated in the policy; failure to pay such premium or breach of any of these obligations, coupled with the occurrence of an event giving rise to a claim, could put us at further risk, as damages - even if insured - would not be covered by the insurer. We cannot guarantee that we will be able to renew our existing insurance policies at reasonable rates, and if renewed, we cannot guarantee that they will be renewed under the same conditions and coverage originally acquired, or at reasonable commercial rates, or on acceptable terms, whether in terms of costs or coverage. Losses caused by events not covered by insurance, or partially covered, may cause us to incur significant costs and the resources available to maintain our current activities and allocated towards our expansion activities will be reduced, which could ultimately have a material adverse effect on our financial performance and operating results. If we are not successful in addressing issues related to occupational health and safety for our employees and the facilities where we conduct our activities, our results and operations may be negatively affected. Our operational activities are exposed to risk factors that may impact the safety of employees and service providers. Among the main critical risks associated with our sector are: working at heights, excavation work, confined spaces, electrical work, lifting and handling loads, and exposure to chemical products used in operational processes. Failures in managing these risks, whether due to inadequate operational controls, ineffective procedures, or insufficient training, may result in serious accidents, material damage, reputational impacts, and partial or total interruption of activities until corrective measures are implemented. Our operations are subject to extensive federal, state, and municipal legislation related to occupational health and safety. In particular, the Regulatory Standards (NRs) establish mandatory guidelines for accident prevention, worker training, implementation of engineering controls, and adoption of management systems. Failure to comply with these standards may lead to fines, citations, civil, labor and criminal liabilities, as well as the shutdown or interdiction of operational units by the relevant authorities. We cannot guarantee that our current health and safety measures will be sufficient to prevent accidents or ensure full compliance with applicable regulations at all times. The occurrence of a significant occupational accident or a finding of non-compliance could adversely affect our operations, financial condition, results of operations and reputation. If any of our assets are deemed assets dedicated to providing an essential public service, they will not be available for liquidation and will not be subject to attachment to secure a judgment. A substantial portion of our assets, including our water and wastewater treatment plants and sewage collection and treatment facilities, are considered by Brazilian law and the URAE-1 Concession Agreement to be essential for the provision of public services. Accordingly, such assets would not be available for liquidation or attachment to ensure the continuity of the public service provision. Upon expiration or termination of the applicable concession agreements, these assets will revert to the relevant granting authority in accordance with Brazilian law and the terms of such agreements. We cannot assure you that any indemnity we receive for such assets would be equal to their market value or sufficient to reimburse the investments made by us in such assets, which could adversely affect our financial condition. 15 Table of Contents Strikes, work stoppages or labor unrest by our employees or by the employees of our suppliers or contractors could adversely affect our business. Labor-related disruptions, including strikes, protests or other collective actions involving our employees, the employees of our subsidiaries, or workers of suppliers and contractors performing essential functions, could adversely affect our critical operational activities. Such events may result in significant delays, impair the completion of strategic projects, and lead to additional costs associated with contingency measures. We cannot ensure that future strikes, work stoppages or other forms of labor unrest will not affect our operations or administrative routines. Disagreements on issues involving changes in our business strategy, reductions in our personnel, or changes to employee contributions and benefits could lead to labor unrest. Disputes arising from these or other matters may give rise to conflicts of interest that could disrupt our operations, administrative processes or project execution timelines. Strikes, work stoppages or other forms of labor unrest at our company or our subsidiaries, or at any of our major suppliers or contractors, could impair our ability to complete major projects and adversely affect our results of operations, financial condition and ability to achieve our long-term objectives. For further information regarding strikes, labor unions and work stoppages, see "Item 6.D. Directors, Senior Management and Employees — Employees." We are subject to obligations regarding respect for the human rights of all of our stakeholders, which may result in additional costs and significant contingencies. We are required to comply with to legal, regulatory and normative obligations related to the respect, promotion and protection of human rights for all stakeholders with whom we interact. Compliance with such obligations may result in additional costs, the need for structural investments and the identification of material contingencies. Failure to comply with these requirements may adversely affect our reputation, operations and financial condition. We are exposed to social risks arising from adverse, potential or actual impacts that our operations may have on the human rights of employees, customers, suppliers, investors and local communities, whether through direct or indirect relationships with our activities. These risks include, among others, inadequate working conditions, violations of occupational health and safety standards, discrimination, harassment and other practices inconsistent with labor laws, industry norms and international expectations. It is essential to ensure a safe, healthy and non-discriminatory work environment, as well as to safeguard the right to freedom of association and participation in labor unions, in accordance with applicable legislation. The identification of an unsafe, hostile or discriminatory workplace may expose us to civil, administrative and labor liabilities, result in operational disruptions, increase employee turnover and impair our ability to attract, retain and develop talent. In addition, the absence of structured and continuous initiatives aimed at promoting diversity, equity and inclusion across our workforce—including in leadership and management positions—may heighten reputational risks, increase stakeholder scrutiny, weaken our competitive positioning and lead to legal or regulatory challenges. We cannot assure that we will be able to fully mitigate these social risks or maintain continuous and comprehensive compliance with all national and international standards, guidelines and expectations related to human rights. Any failure to do so may result in material adverse effects on our operating results, corporate reputation and financial condition. If we do not remedy the material weakness in our internal controls, the reliability of our financial statements could be materially affected. Our management is responsible for establishing and maintaining adequate internal control over financial reporting and for evaluating and reporting on the effectiveness of our system of internal control. Our internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external reporting purposes in accordance with IFRS Accounting Standards. As a public company, we are required to comply with the Sarbanes-Oxley Act and other rules that govern public companies. In particular, we are required to certify our compliance with Section 404 of the Sarbanes-Oxley Act, which requires us to furnish annually a report by management on the effectiveness of our internal control over financial reporting. In addition, our independent registered public accounting firm is required to report on the effectiveness of our internal control over financial reporting. 16 Table of Contents A “material weakness” is a deficiency, or a combination of deficiencies, in internal control over financial reporting, such that there is a reasonable possibility that a material misstatement of the annual or interim financial statements would not be prevented or detected on a timely basis. In the course of completing our assessment of internal control over financial reporting as of December 31, 2025, we did not design or maintain effective internal control due to material weaknesses identified as of that date. These material weaknesses were related to the identification, design and execution of relevant controls in information technology general controls (ITGC) and related information produced by the entity that support underlying data used in all routine and non-routine business and financial reporting processes and controls, to fully address the requirements of the COSO criteria. These material weaknesses did not result in any identified misstatements to the consolidated financial statements and there were no changes to previously released financial results. Although these material weaknesses did not result in any material misstatement of our consolidated financial statements for the periods presented, they could lead to a material misstatement of account balances or disclosures. Accordingly, management has concluded that these control deficiencies constitute material weaknesses. Our internal controls department is responsible for overseeing the implementation of action plans and reports periodically to the Board of Directors and the Audit Committee. If our future efforts are not sufficient to remedy all the inconsistencies identified, we could continue to experience material weaknesses in our internal controls in the future. Any such material weaknesses could adversely affect our ability to accurately prepare our financial statements, which may result in a restatement of our historical financial statements or in misstatements in our future financial statements and, consequently, adversely affect our business and financial condition. See “Item 15-Controls and Procedures” for further details. Transactions with related parties, including as part of our privatization, may not have comparable market terms available and may not be entered into on an arm’s length basis, which could expose us to lawsuits and affect our financial results. We were a company controlled by the State of São Paulo and certain transactions that we entered into with companies controlled by the State of São Paulo or governmental entities have no comparable market terms available. Additionally, we cannot guarantee that these transactions have been entered into on an arm’s length basis. This risk remains even following our privatization as the State of São Paulo remains our significant shareholder. Furthermore, we must comply with Brazilian antitrust and competition regulations, as well as with the disclosure requirements of the CVM, the SEC, and the stock exchanges on which our securities are listed. Any noncompliance with applicable requirements relating to related party transactions could adversely affect our financial condition, may result in regulatory penalties and may expose us to lawsuits from third parties. Risks Relating to Suppliers We cannot guarantee that our suppliers and/or outsourced service providers will not engage in any irregular practices. We rely on suppliers and outsourced service providers for the performance of a significant portion of our operational and expansion activities. We cannot guarantee that such third parties will not engage in improper, unlawful or non-compliant practices under applicable legislation, including anti-corruption, environmental, labor, and regulatory standards. Any involvement of suppliers or service providers in acts of corruption, fraud, collusion, labor or environmental irregularities may result in investigations, administrative or judicial sanctions, fines, restrictions on contracting with the public sector, contract termination, suspension of works or services, as well as significant reputational damage. 17 Table of Contents Even if such acts are committed by third parties, we may be held jointly or secondarily liable, or may suffer indirect impacts arising from the interruption of activities and the need to replace suppliers. The materialization of these risks may adversely affect our financial condition, operating results, and reputation. Any interruptions in the supply of electricity and water may adversely affect our operations. Electricity and the price we pay for it have a significant impact on our operating results. Any material interruptions in the supply of energy could have a considerable negative effect on our activities, financial condition, results of operations and prospects. The Brazilian power generation system is based on hydro, thermal, wind and solar energy, with the majority of energy being produced by hydroelectric powerplants. It is not possible to predict rain patterns in the future. Increases in the price of energy could have a material impact on our business, financial condition, or results of operations. Moreover, electricity shortages could lead to instability in water supply and sewage collection and treatment services, which could adversely affect our reputation and operations. Additionally, as one of the largest electricity consumers in the State of São Paulo, a potential increase in electricity tariffs due to a shortage of hydroelectric power could have a significant financial impact on us. Finally, adverse weather conditions and continuous droughts can interrupt the electricity supply and may impact our distribution of water and prevent us from providing water to our customers and perform our obligations in accordance with the terms of our concession agreements. For more information, see “Item 4.B. Business Overview—Power Consumption.” Our business is subject to risks arising from reliance on services and products from third-party suppliers. Our ability to operate our systems and execute construction projects within planned deadlines and budgets may be negatively impacted by dependence on third-party suppliers and service providers for the supply of materials, equipment, services, and products. We rely on these third parties to carry out the works required to meet regulatory targets for universalization of sanitation, and the technical capability, operational performance, and financial stability of these suppliers are critical factors for delivering projects within the expected timelines and budgets. This dependence involves risks of shortages of critical inputs, such as high-density polyethylene (HDPE), polyvinyl chloride (PVC) and concrete pipes, for which demand may, at certain times, exceed the available production capacity. There are also risks related to the limited availability of equipment, such as micro-tunneling machines, high-speed drilling rigs (HDD) and compact lift stations, which have few qualified manufacturers and, in some cases, are not produced domestically, potentially causing significant delays or requiring urgent importation. We depend on a limited number of suppliers for chemicals used in water and sewage treatment processes, inputs that are essential for maintaining the quality, safety, and continuity of public service provision. Additionally, financial difficulties, bankruptcy, work stoppages, contractual breaches, or serious health and safety failures by third parties may result in delays, increased costs, administrative sanctions, liability for us, and reputational impacts. Competition with other sectors of the economy for similar professionals, equipment, and materials may further intensify price pressures and temporary unavailability. In this context, failures in the supply capacity or execution by third parties may result in interruptions, delays, or significant additional costs, affect compliance with regulatory targets and contractual commitments related to the expansion, operation, and modernization of infrastructure, and generate adverse impacts on our financial condition, operating results, and reputation. Risks Relating to Our Clients We are owed some substantial unpaid debts. We cannot assure you as to when or whether we will be paid. Historically, the State of São Paulo and some State entities have delayed payment of substantial amounts related to water and sewage services owed to us. As of December 31, 2025, the State of São Paulo owed us R$122.5 million for water and sewage services. Additionally, the State of São Paulo also owes us substantial amounts related to reimbursements of state-mandated special retirement and pension payments that we make to some of our former employees for which the State of São Paulo is required to reimburse us. 18 Table of Contents With respect to payment of pensions on behalf of the State of São Paulo, we had a disputed credit of R$1.8 billion as of December 31, 2025, recorded in the line item “disputed amount”. We have not recorded this disputed amount as a reimbursement credit for actuarial liability due to the uncertainty of payment by the State of São Paulo, considering that the amount is under judicial discussion in a civil lawsuit filed on November 9, 2010, against the State of São Paulo. We also had an uncontested credit of R$1.0 billion which is recorded as related-party receivables, recorded in the line item “undisputed amount”. For further information, see Note 11 to our 2025 Consolidated Financial Statements. In addition, as of December 31, 2025, we recorded a provision for an actuarial liability of R$ 2.0 billion with respect to future supplemental pension payments for which the State of São Paulo does not accept responsibility. For further information, see Note 25 to our 2025 Consolidated Financial Statements. In addition, certain municipalities and other government entities also owe us payments. We cannot assure you when or if the State of São Paulo and such municipalities will pay the contested credits, which are still under discussion, and the remaining overdue amounts they owe us. The amounts owed to us by the State of São Paulo, municipalities and other government entities for water and sewage services and reimbursements for pensions paid may increase in the future, given that we are currently making some payments on behalf of the State of São Paulo. Risks Relating to Our Management We depend on the technical qualifications of the members of our management and certain key employees, and we cannot guarantee that we will be able to retain them or replace them with equally qualified individuals. Part of the success of our operations and the implementation of our strategy depends on the knowledge, skills, and efforts of our management and certain key employees. If members of our management or such employees choose to no longer participate in the management of our business and/or resign, we may not be able to find qualified professionals to replace them. The New Legal Framework for Basic Sanitation set a target of December 31, 2033 for the universalization of water and sewage services in Brazil. However, in relation to the Concession Agreement for URAE-1, this date was brought forward to December 31, 2029. The increase in the number of companies operating in our industry, as a result of the New Legal Framework for Basic Sanitation, may lead members of our management or other professionals to leave us. The loss of members of management and key employees, as well as the difficulty in recruiting professionals with equivalent expertise and experience, could have a negative effect on our results of operations, financial condition, and reputation. Risks Relating to the Regulatory Environment Regulatory conditions for access to federal funding and financing pose risks to our ability to obtain resources necessary for our operations and investments. Access to federal public funds and financing supported by Brazilian government resources, or by resources managed or operated by Brazilian federal agencies or entities, is subject to several specific regulatory conditions. Failure to meet any of these requirements may limit our ability to obtain such funding, increase our financing costs, or delay planned investments. As provided for in Federal Law No. 11,445/2007 and Federal Decree No. 11,599/2023, these conditions include: (i) achievement of minimum performance indicators, related to technical, economic, and financial management, as well as efficiency and effectiveness in service provision; (ii) proper operation and maintenance of previously financed projects; (iii) compliance with the ANA reference standards for the regulation of basic sanitation services, including compliance by ARSESP; (iv) compliance with losses targets in the water distribution system; (v) timely submission of updated information to the National Information System for Basic Sanitation (SINISA); and (vi) regulatory compliance of the operation to be financed. 19 Table of Contents If we do not meet these conditions, we may become ineligible to access certain federal funds or financing programs, which could reduce our access to specific funding sources or require us to seek alternative financing on less advantageous terms. Any such limitations could adversely affect our investment program, operational performance, and financial condition. Pursuant to the New Legal Framework for Basic Sanitation, ANA will be responsible for issuing reference standards. Any non-compliance will prevent municipalities or operators from accessing financings and public resources managed or operated by the Brazilian government. According to Federal Law No. 11,445/2007 and Federal Law No. 9,984/2000, both modified by the New Legal Framework for Basic Sanitation on Federal Law No. 14,026/2020, ANA can issue reference standards (guidelines) for how subnational regulatory agencies should regulate certain topics in the sector. Consequently, ANA’s reference standards can apply to the basic sanitation sector nationwide, setting the guidelines for regulation and supervision by the regulatory entities at the state, municipal, and district levels, and ensuring regulatory uniformity in the sector and legal certainty for the provision and regulation of the service. Nevertheless, the application of the reference standards is not mandatory a priori. The New Legal Framework for Basic Sanitation provided that the access to financing and public resources managed or operated by the Brazilian government depends on compliance with the reference standards, by the sanitation service titleholders, service providers, and the subnational regulatory agencies, such as ARSESP. Accordingly, there is an incentive for adherence to these reference standards. If ARSESP and/or any other regulatory agency responsible for overseeing and supervising the services provided by us do not adopt ANA’s reference standards, we will be ineligible for federal funding. In this case, we would be unable to execute financing agreements with federal public banks. Access to federal funding is also contingent upon compliance with the additional requirements established in Article 50 of the New Sanitation Legal Framework. Moreover, Federal Decree No. 11,468/2023 created the National Secretariat for Environmental Sanitation, linked to the Ministry of Cities, with several competences, including: (i) coordination of the implementation of the Federal Basic Sanitation Policy in Brazil; (ii) proposition of national guidelines for financing the sanitation sector; and (iii) definition of guidelines for the preparation of reference standards. Non-compliance by any municipalities with the reference standards could adversely affect our activities, especially as we and any non-complying municipalities would be prevented from accessing public resources from the Brazilian government. We are exposed to risks associated with the Concession Agreement for URAE-1, which may materially impact our financial condition and operating results. Pursuant to the Concession Agreement for URAE-1, there is an allocation of risks between the granting authority and us. We are responsible for risks inherent to our business operations, including but not limited to: (i) Failures, errors, or omissions in the engineering projects necessary for investment execution, including execution methodology and/or technology used by us, or in the surveys that supported them; (ii) Costs arising from obsolescence, instability, and malfunctioning of the technology employed by us in our services; (ii) Shortfalls or fluctuations in tariff revenue established by the São Paulo State Public Services Regulatory Agency (ARSESP); (iv) Costs and delays resulting from the late obtainment of licenses, authorizations and/or permits, arising from our failure to comply with the terms and conditions set forth in the Authorizations Plan approved by ARSESP; and (v) Negligence, lack of skill, or recklessness by individuals working for us. 20 Table of Contents If any of these risks materialize, we may not be entitled to an economic-financial rebalancing of the contract and may consequently face increased costs and/or reduced revenues, which could impact our results of operations and financial condition. In addition, pursuant to the Concession Agreement for URAE-1 and the internal regulations of the URAE-1 deliberative council, any municipality could withdraw from the Concession Agreement for URAE-1. The withdrawal of a municipality, particularly one that generates a significant portion of our revenue — such as the city of São Paulo — could have a material adverse effect on our business and results of operations. However, a municipality’s decision to withdraw from URAE-1 is subject to the prior payment of the indemnification amounts owed to us, without prejudice to our continuing to operate the services until full payment of the amount due is made. In the case of municipalities that are part of a metropolitan region, urban agglomeration, or microregion and that share operational facilities, any withdrawal must be submitted for approval by the other municipalities that are part of URAE-1. Moreover, in the event of contractual noncompliance, such as failure to meet key performance indicators, we may be subject to penalties, which can be imposed only after an administrative proceeding conducted in accordance with the due process requirements set forth under Brazilian law. In addition to the application of such penalties, tariff discounts may also be applied through universalization factor (“Factor U”) and/or Factor Q, which relate, respectively, to the achievement of universalization targets and the quality of the services provided. As ARSESP is responsible for implementing tariff adjustments and conducting periodic and extraordinary reviews of the Concession Agreement for URAE-1, we cannot guarantee that ARSESP will approve tariff adjustments in a timely manner or accept the imbalance events presented by us during periodic and extraordinary reviews. Any refusal and/or delay in applying tariff adjustments or any failure to restore the contractual economic-financial balance may impact our results of operations and financial condition. Finally, the granting authorities have the right to terminate these agreements early under the circumstances set forth in Section 35 of Federal Law No. 8,987/1995 (the “Brazilian Concessions Law”), such as: • Forfeiture (Caducidade): early termination due to (i) inadequate or deficient service provision; (ii) material breach of contractual obligations; (iii) unjustified interruption of services; or (iv) loss of the economic, technical, or operational capacity necessary to provide the service adequately. We are entitled to a cure period before administrative proceedings for forfeiture are initiated. • Takeover (Encampação): early termination based on a public-interest decision, duly justified and approved by law, upon demonstration that continuation of the concession is no longer in the public interest. Any early termination must be preceded by an administrative proceeding in which we will have the opportunity to present our defense and contest the indemnification amount. It is not possible to predict how long such proceedings will take or whether we will receive the compensation we consider appropriate. Under each concession agreement, we are entitled to compensation for investments that have not yet been amortized or depreciated. In the event of takeover, compensation must be paid prior to termination, while forfeiture does not require prior payment. Any such early termination could have a material adverse effect on our results of operations, financial condition, and reputation, as well as the trading price of our common shares and ADSs. For more information, please see “Item 4.B. Business Overview— Contract URAE-1— Tariffs.” If we do not meet the targets established by the Concession Agreement for URAE-1, our tariff adjustments might be reduced, which could materially adversely affect our business, financial condition, or results of operations. The New Legal Framework for Basic Sanitation established December 31, 2033 as the deadline for achieving universal access to water supply (99% of the population) and sewage services (90% of the population) in Brazil. However, in relation to the Concession Agreement for URAE-1, this deadline was brought forward to December 31, 2029. The universalization deadline also applies to rural areas and consolidated informal urban areas, which were included in our service area by the Concession Agreement for URAE-1. 21 Table of Contents Monitoring compliance with the universalization targets shall be evaluated based on the indicators and timelines set out in the Technical Annex for each municipality (Annex II of the Concession Agreement for URAE-1). If the universalization targets are not achieved, the tariff adjustment index (Índice de Reajuste Tarifário – “IRT) may be reduced through the application of Factor U, which could materially and adversely affect our business, financial condition, or results of operations. ARSESP is responsible for calculating the Factor U at each tariff adjustment and periodic tariff review, using information provided by the independent verifier. The distribution of dividends by us is prohibited in the event of non-compliance with the universalization targets and schedules provided for in the Concession Agreement for URAE-1, as determined in a regular administrative proceeding and decided with final effect by ARSESP. In addition to the application of Factor U and its potential effects on dividend distribution, ARSESP may impose fines and other sanctions if we are found, during regulatory inspections, to be in non-compliance with the URAE-1 Concession Agreement. In an extreme scenario, repeated failure to meet universalization targets may trigger the early termination of the Concession Agreement for URAE-1 (declaration of forfeiture), if any of the following occur: • failure to achieve at least one of the URAE-1 Coverage Targets for water or sewage services in two consecutive years or in three non-consecutive years within a five-year period starting in 2025; • failure to achieve at least one of the Municipality Coverage Targets for water supply or sewage services — representing at least one-third (1/3) of the municipalities within URAE-1 — in two consecutive years or in three non-consecutive years from 2027 onward, provided that none of the three URAE-1 coverage targets demonstrates any improvement; and/or • the service availability indicator IRFA — Index of User Complaints Related to Water Shortage and Low Pressure — reaching a level equal to or above 95, regardless of the applicable target framework for the calculation of Factor Q, for four consecutive semesters or seven non-consecutive semesters within a five-year period. Any fine, sanction, or early termination of the Concession Agreement can be imposed only following an administrative proceeding conducted in accordance with the due process guarantees set forth under Brazilian law. Although much of the effort to achieve these targets falls on us, there are imponderable elements that are beyond our control, and which could affect our ability to achieve these targets — such as delays in issuing environmental licenses and municipal authorizations to carry out construction works, processes for vacating areas of interest, the possible finding of archaeological sites, among others. We will not be held liable for any failure to achieve the universalization targets if such failure results from omissions or delays by URAE-1, the municipalities, or the State in fulfilling their respective obligations. The granting/contracting authorities may terminate contracts before they expire in certain circumstances. The indemnification payments we receive in such cases may be less than the value of the investments we made, or may be paid over an extended period, adversely affecting our business, financial condition, or results of operations. The granting authorities — the contracting entities that delegate the provision of public services to us through concession agreements, such as URAE-1 and the municipality of Olímpia — have the right to terminate these agreements early under the circumstances set forth in Section 35 of Brazilian Concessions Law. Early termination may occur in the following cases: • Forfeiture (Caducidade): early termination due to (i) inadequate or deficient service provision; (ii) material breach of contractual obligations; (iii) unjustified interruption of services; or (iv) loss of the economic, technical, or operational capacity necessary to provide the service adequately. We are entitled to a cure period before administrative proceedings for forfeiture are initiated. 22 Table of Contents • Takeover (Encampação"): early termination based on a public interest decision, duly justified and approved by law, upon demonstration that continuation of the concession is no longer in the public interest. • Annulment: early termination due to a subsequently identified illegality that cannot be remedied, such as legal defects in the bidding process. • Bankruptcy or dissolution of the concessionaire. In addition to the grounds set forth in the Brazilian Concessions Law, the initiation of judicial or extrajudicial reorganization proceedings may also lead to early termination, depending on the terms of each contract. Any early termination must be preceded by an administrative proceeding in accordance with the due process requirements set forth under Brazilian law. We will have the opportunity to present our defense and contest the indemnification amount. It is not possible to predict how long such proceedings will take or whether we will receive the compensation we consider appropriate. In cases of forfeiture, annulment (when we or our controlling shareholders contributed to the illegality), or bankruptcy, additional penalties may be imposed, including suspension of the right to participate in future public tenders. Under each concession agreement, we are entitled to compensation for investments that have not yet been amortized or depreciated. In the event of takeover, compensation must be paid prior to termination, while forfeiture does not require prior payment. At the federal level, ANA issued Reference Standard No. 03/2023, approved by Resolution No. 161/2023, which establishes the methodology for compensating unamortized or undepreciated investments in water supply and sewage services. This standard applies to contracts entered into before and after its issuance and must be followed by subnational regulatory authorities when issuing their own rules. In municipalities within the State of São Paulo regulated by ARSESP, Deliberation No. 1,515/2024 must be observed regarding asset reversion and compensation at the end of concessions. This Deliberation was issued by ARSESP based upon the aforementioned ANA Reference Standard No. 03/2023. However, with respect to the URAE-1 Concession Agreement, the contractual methodology prevails, and ARSESP’s regulation applies only on a subsidiary basis. For other municipalities regulated by ARES-PCJ, such as Olímpia, Resolution No. 648/2025 applies on a subsidiary basis to the methodology established in the applicable concession agreement. Even with the guarantee of due process, adversarial rights, and the correction of irregularities (particularly regarding forfeiture), we cannot rule out the possibility that granting authorities may terminate concession agreements early under the circumstances described above. If early termination occurs and we do not receive adequate compensation, or if compensation is significantly delayed, our business, financial condition, and operating results could be adversely affected. We also cannot predict the impact that methodologies adopted by the relevant regulatory authorities — when applied on a subsidiary basis — may have on our business, including the risk that compensation payments may be lower than the remaining value of our investments. Additionally, municipalities may refuse to pay indemnification voluntarily, potentially leading to judicial disputes. In such cases, there is a risk that judicial decisions could result in indemnification being set at a lower value or deemed undue. We are also a party to proceedings related to indemnification issues regarding the resumption of water supply and sewage collection services by certain municipalities. For more information, see “Item 3.D. Risk Factors — Risks Relating to Environmental Matters and Physical and Climate Transition Risks.” If the water from our water sources (mananciais) does not meet our water treatment conditions, we may have to interrupt the water treatment process until we are able to treat the water or to substitute the supply of water from another water source. Our water supplies are potentially subject to contamination by sewage infiltration into our water distribution networks, which can alter their quality. If this occurs, we do not distribute the contaminated water and maintenance and disinfection is carried out in the distribution network, which generates additional costs for our business. 23 Table of Contents In addition, water sources may possibly be contaminated by third parties through irregular or accidental dumping of large quantities of pollutants affecting the final quality of the water and impact the result for the quality of services factor (Factor Q - ICAD) on tariff adjustment. Risks of contamination in our distribution system include potential failures in network maintenance procedures, which may carry unwanted material to the supply network. If we are found liable for water contamination resulting in human exposure to hazardous substances, we could face administrative, civil and/or criminal enforcement actions, litigation, and other proceedings or obligations to remediate environmental damages and compensate affected individuals. Such incidents could also significantly harm our reputation. Environmental remediation and compensation typically involve significant costs and may last several years. Additionally, claims or complaints from residents or communities near our sites may have adverse effects on our business, reputation, or ability to obtain funding, especially from multilateral institutions. Failure to effectively manage these claims could adversely affect our results of operations, financial condition, and reputation. Furthermore, cleaning up water sources can be costly and if we are required to do so, it could have a material and adverse effect on our business, results of operations, and financial condition. If our water supply fails to meet treatment standards, we may have to interrupt or stop the use of that water supply until we can treat the water or replace it with water from another source. Adapting the treatment process, either by expanding current facilities or developing new methods, could incur significant costs. Using a more distant water source may also result in increased expenses. Additionally, if we need to interrupt the water supply, we will have to notify our consumers, further impacting our operations. Additionally, the increase in the population density of the contributing basins is another factor that may reduce the availability of raw water. Any decrease in the amount of raw water available to us could have a negative effect on our financial results and activities. Water and sewage treatment involve environmental risks in the event there is a system failure. For example, if there is an overflow in a sewage treatment plant, the sewage could impact neighboring areas or even natural water resources, which could have a material adverse effect on our reputation, financial condition, and results of operations. In addition, sludge, a byproduct of the sanitation process, needs to be disposed of appropriately in order to prevent harm to the environment. In some cases, the landfills in which the sludge is deposited are not located in the same municipalities as the water and sewage treatment facilities and, therefore, we are required to transport the sludge to the closest landfill, which increases the risk of contamination. Furthermore, some landfills may stop operating, which may increase our operating costs. These events could also lead to environmental liabilities in the administrative, criminal, and civil spheres, as mentioned above. Any of the above events could have a material adverse effect on our results of operations, financial condition, cash flow, liquidity, and reputation. Risks associated with the collection, treatment and disposal of wastewater and the operation of water utilities may impose significant costs that may not be covered by insurance, which could result in increased insurance premiums. The wastewater collection, treatment, and disposal operations of our utilities are subject to substantial regulation and involve significant environmental risks. If collection or sewage systems fail or do not otherwise operate properly — including as a result of pipe leaks, bursts, or overflow — untreated wastewater or other contaminants could spill onto nearby properties or into nearby streams and rivers, potentially causing damage to persons or property, harm to the environment (including aquatic life), and economic losses that may not be recoverable through tariff rates. This risk is most acute during periods of substantial rainfall or flooding, which are among the principal causes of sewer overflow and system failure. Liabilities resulting from such damage could materially and adversely affect our business, results of operations, and financial condition. If we are deemed liable for any damage caused by such failures, losses might not be covered by our insurance policies, and such losses may make it difficult for us to secure insurance in the future with the same coverage and coverage limits at acceptable premium rates. Similarly, any related business interruption or other losses might not be covered by insurance policies, which would also make it difficult for us to secure insurance in the future at acceptable premium rates. 24 Table of Contents We may also incur liabilities under environmental laws and regulations requiring the investigation and remediation of environmental contamination at our properties or at off-site locations where there have been adverse environmental impacts. The discovery of previously unknown conditions, or the imposition of cleanup obligations in the future, could result in significant costs and could materially and adversely affect our reputation, financial condition, results of operations, cash flows, and liquidity. Such remediation losses may not be covered by our current insurance policies, or the insured amount may not be sufficient, and may make it difficult for us to obtain comparable insurance coverage in the future at acceptable premium rates. We cannot guarantee that our existing insurance policies provide comprehensive coverage for all circumstances that may arise or all inherent risks, that they would cover all potential damages claimed, or that we will be able to renew our existing insurance policies, or on what terms any such renewal could be obtained. The occurrence of a significant uninsured or uninsurable loss, in part or in full, or the failure of our subcontractors to comply with their indemnity obligations, may materially and adversely affect our results of operations, financial condition, and reputation. We are exposed to risks of delays or failures in payments associated with the provision of water and sewage services. According to our contracts, we are required to achieve specific service targets and continue supplying water and sewage services to clients with overdue or irregular payments. In these situations, we cannot guarantee when payments for the services will be received, despite the existence of administrative and judicial procedures for the collection of outstanding debts. As a result, we may experience delays or shortfalls in cash collections, which could adversely affect our liquidity and working capital. Meanwhile, we incur significant costs for providing these public services, like water abstraction and sewage discharge fees, and there is a risk we may not be able to fully pass these costs on to our customers. In addition, increases in such costs or limitations imposed by regulatory authorities on our ability to recover them through tariffs could negatively impact our margins. However, under the URAE-1 Concession Agreement, the tariff adjustment mechanism takes into account, among other factors, the level of uncollectible revenue, i.e., revenue that remains uncollected after all commercial and legal collection efforts have been exhausted and that reflects structural default. If the volume of uncollectible revenues increases beyond the level recognized in the tariff adjustment process, or if the regulatory methodology for recognizing such amounts changes, our financial condition and results of operations could be adversely affected. Reducing physical water losses caused by leaks and overflows primarily depends on investments made in leak detection and repairs, pressure management in distribution networks, operational improvements, and the renewal of the distribution network. Reducing levels of non-physical water losses (which result from unauthorized consumption (theft) or inaccurate measurement) depends mainly on investments made in the acquisition and installation of water meters, the re-registration of customers, and combat of irregularities, such as illegal water connections. The URAE-1 Concession Agreement establishes performance indicators with targets for coverage and water loss reduction throughout its term for each municipality. If we do not make sufficient investment in activities and projects to reduce our levels of water losses, we could be materially and adversely affected, including the imposition of fines and the reduction of the tariff adjustment amount related to URAE-1 Concession Agreement. These investments must mainly be aligned with the goals established in concession contracts and the ideal levels of losses in supply systems. Furthermore, the New Legal Framework for Basic Sanitation establishes that providers of public water supply and sewage services must meet qualitative and quantitative targets. Among these targets is the reduction of losses in the distribution of treated water. 25 Table of Contents If we do not implement the necessary actions to reduce the water loss rates, or if the projects aimed at reducing water loss levels do not produce satisfactory results, our cash flow, results of operations, and financial condition may be adversely affected, and we may be penalized by the granting authority if we fail to meet the targets established in the relevant concession agreements related to losses. Such penalties could include financial sanctions or other contractual consequences, further affecting our operational performance. Securing new concessions, new public-private partnerships and new acquisitions involve risks related to the integrations of the adjudicated or acquired businesses, the situation of the assets and the regularity of the operations related to the concessions. Securing new concessions, entering into public-private partnerships or completing acquisitions may expose us to risks related to the integration of the adjudicated or acquired businesses, the condition and adequacy of existing assets, and the regularity of concession-related operations, such as: (i) the assets related to the contract may be different from the description provided in the public bidding documents; (ii) the absence of and/or the irregularity of required environmental licenses; (iii) the absence of grants for the operation of wells; or (iv) land irregularities. We may also encounter difficulties in transferring the assets associated with these contracts, or such assets may be in non-operational condition, requiring additional investments to bring them into compliance with operational or regulatory standards. These irregularities may also complicate, or in some cases prevent, the execution of financing agreements, which could affect our ability to meet the performance targets originally established in our contracts. In the case of companies acquired by us, there may be delays in obtaining the consent of the granting authority or their creditors to confirm the change of control or we may not obtain such consents at all. Furthermore, other factors such as contingencies not identified during due diligence, lack of synergies, failure to integrate activities, among others, may arise. This could result in increased expenses for us and, as a result, impact our financial condition and operating performance. Our expansion strategy includes acquisitions that involve significant risks and uncertainties, which could adversely affect our business, results of operations, and financial condition. As part of our strategy to expand our activities, we may undertake acquisitions from time to time, which will depend on several factors, including our ability to identify suitable companies or assets for acquisition, negotiate acceptable prices and terms, successfully integrate and maintain the quality of operations of the acquired businesses or assets, and realize the expected synergies and cost savings from such integrations. If we are unable to achieve the expected gains from acquisitions, or if acquired assets do not perform or integrate as expected, our business, results of operations, and financial condition could be adversely affected. Potential acquisitions may also require us to incur additional indebtedness or to access the financial and capital markets, including through the issuance of new shares and ADSs. This could result in increased indebtedness and financial exposure, as well as dilution of our existing shareholders’ and ADS holders’ ownership interests in our share capital. Acquisitions also expose us to the obligations and contingencies of the acquired companies or assets arising from acts or omissions of prior management and previously incurred liabilities. Our legal due diligence process to evaluate the legal and financial condition of potential acquisition targets — and any contractual guarantees or indemnities we may receive from our counterparties — may be insufficient to protect us against such contingencies. If significant or unidentified contingencies arise in connection with such acquisitions, they could adversely affect our business, results of operations, and financial condition. We may also encounter difficulties or delays during any acquisition process, and such processes could divert significant time and attention of our management team toward transitional or integration-related matters and away from our core business operations. In addition, corporate reorganizations undertaken in connection with our acquisitions may be subject to review or investigation by competition, antitrust, or other regulatory authorities, which could delay or prevent the completion of such transactions. 26 Table of Contents Any failure or delay in completing future acquisitions or other strategic investment transactions could have a material adverse effect on our business and results of operations. Risks related to encumbrances, which may negatively affect us in the event of default on the obligations guaranteed by our properties. There may be risks in relation to some of our properties that are subject to legal encumbrances and restrictions, such as unavailability and easements (right of way). According to certificates of real estate records, some of our properties are burdened with unavailability, which is a temporary judicial measure that imposes significant restrictions on certain assets and the taxpayer’s rights over those assets, to ensure compliance with and payment of back taxes by the taxpayer before they can dispose of, transfer or use specific assets previously identified by the public treasury as debt security. As a rule, non-payment of debts that lead to the declaration of unavailability can result in the forced sale of the properties, the value of which will be used to pay the outstanding debts. In these cases, the new owners of the properties can request possession of the assets, which may require the relocation of the activities carried out in these locations. In addition, even if the debts that resulted in the declaration of unavailability have already been paid, failure to cancel the encumbrance on property registrations may hinder possible transactions or operations involving such properties in the future. In addition, some of our properties are trapped by easements. In the event that the existing easements are not being respected, the respective beneficiaries may demand that their area be vacated and enforce the real right of these easements, as well as the losses and damages incurred, such as the payment of fines and compensation for any damages caused by the non-compliance with the real right. In addition, beneficiaries can file a lawsuit to ensure that their right of way is respected. Failure to pay the amounts that generated the unavailability can lead to the forced sale of the properties, and the value of any sale will be used to pay off outstanding debts. In these cases, the new owners of the properties may seek possession of the assets, which may lead to the need to relocate the activities carried out in these locations. If we are unable to obtain or renew environmental permits and/or licenses, we may be subject to fines and the closure of any irregular facilities, with the interruption of activities carried out by us at such facilities. We may not be able to keep in force or renew with the appropriate public authorities all permits and/or licenses necessary for our operational assets and for the development of our activities. If we are unable to obtain or renew such permits and/or licenses, we may be subject to fines and the closing of any non-compliant facilities, with the interruption of the activities carried out by us at such facilities. Any factors that impact the failure to obtain or renew such licenses and permits may cause us to incur additional costs, which may force us to reallocate resources to meet any additional charges. Failure to obtain, maintain or renew environmental licenses and authorizations as well as to comply with applicable conditions may result in environmental, administrative, civil or criminal liability, including strict liability for environmental damages under Brazilian law. Additionally, we cannot guarantee that permits, licenses and authorizations, such as use and operating permits and/or documents relating to the regularity of built-up areas, have not been breached in the past when in the process of obtaining or renewing them. For example, the existence of a built-up area without prior authorization from the relevant city hall, or in disagreement with the project approved, could lead to risks and liabilities for the property if the area is not regularized and it is inspected by the competent authorities. These risks include: (i) the impossibility of registering the construction; (ii) the refusal for us to issue an operating license; (iii) the refusal to obtain or renew property insurance; (iv) the imposition of fines; and/or (v) the forced closure of the establishment. 27 Table of Contents According to the Brazilian law regulating concessions and public-private partnership matters, our corporate structure is composed of some special purpose entities, which may result in our responsibility for tax, labor, environmental protection, consumer and bankruptcy matters originated from our subsidiaries. Pursuant to Brazilian Law No. 11,079/2004, the execution of public-private partnerships must be preceded by the incorporation of a special purpose entity (SPE). However, in the event that one of our SPEs does not comply with the contractual obligations or is financially unable to honor the due capital contribution installments, as provided in the public-private partnership agreement, as their controlling shareholder and/or guarantor, we may be liable to perform supplementary investments and to provide additional services in order to maintain the minimum financial rates provided for under the relevant agreements. Brazilian Concessions Law, which establishes provisions for concessions and permission of public services, sets forth that the concessionaire, incorporated as an SPE or not, is responsible for the provision of the service granted in the concession, and is liable for any and all damages to the granting authorities, users or third parties. Oversight by the competent authority does not exclude or mitigate such liability, which could adversely and materially affect our business, financial condition, and results of operations. In the case of the concessionaire being incorporated as a consortium, the consortium leading company is liable before the public grantor for the compliance with the concession agreement, without prejudice to the joint and several liability of the additional members of the consortium. Risks related to our subsidiaries also include bankruptcy and potential enforcement of piercing the corporate veil by the Brazilian Courts. As a rule, the controlling shareholder is liable for damages resulting from acts performed with abuse of power. Any event impacting the image of our partners, business partners and service providers of our subsidiaries may adversely affect our brand. Additionally, we may be liable for certain obligations of our subsidiaries, including tax, labor, environmental protection, regulatory and consumer matters, which, in the event they materialize, may adversely affect our business and results. We are subject to penalties related to our registrations, authorizations, licenses and permits for the development of our activities. We depend on licensing and registration before federal, state and municipal authorities and agencies, as well as operating permits. We cannot guarantee that we will be able to obtain all the necessary licenses, permits and authorizations, or obtain their renewals in a timely manner. Obtaining the necessary licenses, permits and authorizations depends on clearance from environmental agencies and other authorities, whose deadlines we do not control. The failure to obtain or renew such licenses may prevent us from operating our units and lead to suspension and closing of irregular units, as well as the application of fines. Our strategy may be adversely affected if it is impossible to open and operate new units or if the operations of our current units are suspended or terminated due to the failure to obtain or renew the required registrations, permits and licenses, which may adversely affect our results of operations. In addition, we are required to comply with the administrative limitations provided by environmental laws, such as the preservation of environmentally protected areas, and of nature conservation areas (e.g., parks, reserves, protected areas, etc.). Failure to comply with these restrictions may result in penalties and other liabilities, including substantial fines, criminal/administrative sanctions and the obligation to repair and/or indemnify any damages. Risks Relating to Environmental Matters and Physical and Climate Transition Risks Our financial and operating performance may be adversely affected by epidemics, natural disasters and other catastrophes Our financial and operating performance may be adversely affected by the outbreak of pandemics, as well as other catastrophes and health epidemics on a regional or global scale. Such outbreaks may result, at different levels, in the adoption of governmental and private measures, including restrictions, as a whole or in part, on the circulation and transportation of persons, goods and services and consequently, in the closure of private establishments and public offices, interruptions to the supply chain, reduction of consumption in general by the population and increased intervention in their economies. 28 Table of Contents In addition, the occurrence of any of these adverse events may increase delinquencies which can negatively impact our results of operations. Our allowance for doubtful accounts decreased by 88.9% for the year ended December 31, 2025 compared to the year ended December 31, 2024 and decreased by 14.6% for the year ended December 31, 2024 compared to the year ended December 31, 2023. Epidemics, natural disasters and other catastrophes may have a negative and significant effect on the world economy and on Brazil’s economy, and include or may include reduction in the level of economic activity; currency devaluation and volatility; increase in the fiscal deficit and constraints to the capacity of the Brazilian government or state governments to make investments and payments and to contract services or acquire goods; delays in judicial, arbitral and/or administrative proceedings; imposition, even if only temporarily, of a more onerous tax treatment of our business activities; decrease the liquidity available in the international and/or Brazilian market; and volatility in the price of raw materials and other inputs, among other effects. We cannot assure that the occurrence of any of these events and their duration may have material adverse effects on our operating results and financial condition, as well as the trading price of our common shares and ADSs. Noncompliance with environmental laws and environmental liability could have a material adverse effect on us and our reputation. We are subject to extensive Brazilian federal, state and municipal laws and regulations related to human health and environmental protection. These regulations establish requirements for environmental licensing, water use grants, and drinking water quality standards, as well as limits on discharge of non-domestic sources entering effluents into our treatment systems. Additionally, they define the quality standards that treated sewage must meet before being discharged into waterways. We may also face incidents such as leaks or pipe ruptures that can lead to liability for environmental damages, including groundwater and soil contamination, as well as regulatory and environmental infractions. We are a party to several environmental proceedings and could be subject to other types of criminal, administrative and civil proceedings for non-compliance with environmental laws and regulations, including licensing requirements and water grants, that could expose us to administrative penalties and criminal sanctions, such as fines, closure orders and significant indemnification obligations. Furthermore, we are party to commitment terms regarding the regularization of licenses and water grants requirements for our operations. Failure to comply with these terms could result in administrative, civil and criminal liabilities. Such expenses may lead us to reduce expenditure on strategic investments, which may adversely affect our business, financial condition, results of operations or reputation. We are also involved in environmental proceedings related to the discharge of untreated sewage into waterways or the disposal of sludge from treatment plants. These proceedings subject us to civil proceedings and investigations concerning environmental remediation and compensation for damages caused. In addition, we are involved in civil/administrative proceedings challenging the water withdrawn during the 2014-2015 water crisis. Any unfavorable judgment in relation to these proceedings, or any material environmental liabilities, may have a material adverse effect on our reputation, business, financial conditions or results of operations. For more information on these proceedings, see “Item 8.A. Consolidated Financial Statements and Other Financial Information—Legal Proceedings.” For more information on investments in environmental programs, see “Item 4.A. History and Development of the Company—Main Focus of our Capital Expenditure Program,” “Item 4.B. Business Overview—Description of our Activities—Sewage Operations—Sewage Treatment and Disposal,” “Item 4.B. Business Overview—Environmental Matters” and “Item 4.B. Business Overview—Environmental Matters—Environmental Regulation.” 29 Table of Contents Environmental, social and governance considerations could expose us to potential liabilities, increased costs (regulatory or otherwise), compliance failures and reputational harm, including with respect to the B3 Green Shares classification we have been granted. We are subject to a broad range of laws, regulations and other measures that govern a wide range of topics requirements, including those related to matters that extend beyond our core business activities. New or amended laws, regulations, policies, and international accords relating to ESG matters, including sustainability, climate change, human capital and diversity, are being developed and formalized implemented in Brazil, the U.S. and elsewhere other jurisdiction, which may require us to comply with specific, target-driven frameworks and/or disclosure requirements. In the U.S., the SEC adopted broad climate change disclosure requirements in March 2024, which were subsequently stayed and vacated. The regulatory landscape in this area remains uncertain and subject to further developments, which may require significant compliance efforts if new rules are adopted in the future. The scope, timing and final form of any of these regulations or other measures is still uncertain. The implementation of these goals and initiatives, as well as compliance with emerging regulatory obligations, and forward-looking milestones may require considerable management time and may result in significant expense to us, and we cannot guarantee that we will achieve our objectives. Moreover, increasingly different stakeholder groups have divergent views on ESG matters, which increases the risk that any action or lack thereof with respect to ESG will be perceived negatively by at least some stakeholders and adversely impact our reputation. Emerging regulatory frameworks may also impose additional compliance burdens and costs on us, and as with any new or developing regulation, may be subject to differing interpretation, which could increase the risk of unintentional noncompliance. Our business could be negatively affected by increased regulation of ESG research, ratings and data. Moreover, increasingly different stakeholder groups have divergent views on ESG matters, which increases the risk that any action or lack thereof with respect to ESG will be perceived negatively by at least some stakeholders and adversely impact our reputation. Such regulatory regimes could impose significant compliance burdens and costs on us, and as with all new regulation, we could be subject to ambiguous interpretation that could result in inadvertent noncompliance. Our business could be negatively affected by increased regulation of ESG research, ratings and data. Additionally, on June 7, 2024, the B3 granted us the B3 Green Shares (B3 Ações Verdes) classification. In compliance with Circular Letter No. 002/2024-VPE, dated May 7, 2024, issued by the B3, S&P Global Ratings Shades of Green (the “Specialized Consultant”), certified that we met the criteria established by B3 and that we derive: (i) more than 50.0% of our annual gross revenue from activities contributing to the green economy; (ii) more than 50.0% of our annual investments and operational expenses allocated to activities contributing to the green economy; and (iii) less than 5.0% of our annual gross revenue derived from fossil fuel activities. However, as the B3 Green Shares classification is provided by a Specialized Consultant, which is a third-party provider, there is no assurance that the scrutiny process meets investor criteria and expectations. We are the first company in Brazil to obtain the B3 Green Shares seal, and there are no standardized processes and regulatory frameworks for this classification. Accordingly, we cannot assure that we will continue to meet the criteria and expectations regarding environmental impact and sustainability performance in upcoming years, and we can give no assurance that we will continue to meet the requirements, voluntary taxonomies or standards, whether currently in place or implemented in the future, to maintain this classification. Any failure, or perceived failure, by us to comply fully with ESG laws and regulations or meet evolving and varied stakeholder expectations and standards could harm our business, operating results, and financial condition. Droughts, such as the 2014 – 2015 water crisis, can cause a material impact on consumption habits and, consequently, on our business, financial condition or results of operations. Severe drought events, such as the drought resulting from the low rainfall levels recorded in the summer of 2014, which resulted in the 2014–2015 water crisis, can have a material impact on consumption habits and, consequently, on our business, financial condition, and operating results. Periodically, we face restrictions in water availability due to prolonged droughts. 30 Table of Contents In recent years, the production systems that supply the Metropolitan Region of São Paulo (RMSP) have recorded rainfall below expectations for two consecutive hydrological years, especially the 2024–2025 cycle, which presented the lowest rainfall volumes of the last seven years. Prior hydrological years also recorded below-average rainfall, including the 2019–2020, 2020–2021, and 2023–2024 cycles, demonstrating a pattern of recurring drought events in our areas of operation. This scenario culminated in SP-Águas Deliberations No. 11 and No. 12, of September 2025, which declared a situation of water scarcity in the Alto Tietê and Piracicaba basins, respectively. The reduction in rainfall levels compromises the recovery of reservoir levels, which are essential to guarantee supply during the dry season, which extends from April to September. It is not possible to accurately predict the future behavior of rainfall, especially given the effects of ongoing climate change. The occurrence of consecutive periods of severe drought may require us to adopt additional measures to mitigate impacts and ensure the continuity of water supply in our areas of operation. During the 2014–2015 water crisis, the levels of the main water sources that supply the São Paulo Metropolitan Region were significantly affected, which led us to implement, between 2014 and 2016, a set of operational and demand management measures to maintain the water supply to the population. These measures were gradually discontinued from 2016 onwards, with the recovery of reservoir levels. However, greater public awareness of the need for rational water use, resulting from that crisis and more recent drought events, has contributed to maintaining lower consumption patterns. Sustainable water resource management and the recurrence of scarcity events may continue to influence consumption habits, with potential adverse impacts on our revenues and operating results. Considering the observed history, there is a risk of new droughts occurring in the future, which may require us to adopt measures similar to or more restrictive than those implemented in 2014–2015, resulting in additional and potentially significant changes in consumption patterns. These uncertainties could adversely and materially affect our financial condition and operating results. Extreme weather conditions and climate change may have a material adverse impact on our business, financial condition or results of operations. Our business may be affected by droughts, and by other extreme weather conditions, such as torrential rain and other changes in climate patterns. A possible increase in the severity of extreme weather conditions in the future may adversely affect the water available for abstraction, treatment, and supply, whether from the standpoint of quality or quantity. Droughts could adversely affect the water supply systems, resulting in a decrease in the volume of water distributed, and consequently, the volume of water billed (i.e., the revenue derived from water supply services). Extreme climate conditions may compromise our facilities’ conditions to operate and supply of inputs. Additionally, increases in air temperature could affect demand for water. Since we are dependent upon energy supplies to conduct our business, extreme weather events may also reduce water levels in the reservoirs that power hydroelectric power plants in Brazil, which may cause energy shortages, which could affect water and sewage services. Increased electricity prices may also adversely affect our costs and results of operations. For more information, see “Item 3.D. Risk Factors—Risks relating to Our Suppliers—Any interruptions in the supply of electricity and water may adversely affect our operations” and “Item 4.B. Business Overview—Power Consumption.” In February 2023, there were torrential rains on the northern coast of the State of São Paulo, especially in the city of São Sebastião, where we operate. Within 24 hours, 683mm of rain fell in São Sebastião. As a result, our water treatment plants in the region were damaged, and the water supply was interrupted for a few days due to siltation, the inability to store water, and lack of electricity. If similar incidents occur in the future or become more frequent, these events may have other additional material adverse effects on our results of operations and financial condition. We cannot predict all of the effects of extreme weather events, making it difficult to estimate the resources needed to mitigate these effects. It is possible that as a result of the difficulty to predict these events, we may be required to make other significant investments or incur substantial costs in their remediation or prevention measures, which may have a material adverse impact on our business, financial condition or results of operations. We also cannot guarantee that we will be able to pass on any of these additional costs and expenses to our customers. 31 Table of Contents New laws and regulations relating to climate change and changes in existing regulation may result in increased liabilities and increased capital expenditures, which could have a material adverse effect on us. We are subject to federal, state and international climate change regulations aimed at reducing greenhouse gas (“GHG”) emissions. Among these, Decree No. 65,881/2021 formalizes the State of São Paulo’s commitment to global initiatives such as the “Race to Zero” and “Race to Resilience” campaigns, which focus on lowering emissions and enhancing climate resilience. The decree also mandates the development of the 2050 Climate Action Plan (PAC 2050) by the State of São Paulo government, which is expected to set sector-specific emissions targets, including for the sanitation industry. Additionally, further regulations may impose additional obligations. For example, Law No. 15,402/2024 establishes the Brazilian Greenhouse Gas Emissions Trading System (or the Brazilian Carbon Market Regulation), which introduces a framework for capping GHG emissions and trading carbon-related assets. Given Brazil’s commitments under international climate agreements, the state government’s firm stance on reducing emissions, and the establishment of new legislation, we may be required to increase investment in emission mitigation measures by (i) enhancing operational efficiency and adopting more sustainable processes to reduce GHG emissions; (ii) implementing infrastructure and equipment to capture and utilize biogas and process-generated sludge; (iii) expanding the use of clean and renewable energy sources and alternative fuels; and (iv) offsetting GHG emissions through intensified conservation and reforestation initiatives. Compliance with evolving climate change regulations present significant challenges due to may be particularly challenging given the complexity and scale of our operational facilities operations, where changes in process design can impact both our existing and future operations activities. In March 2024, the SEC approved new climate-related disclosure rules that would have required public companies to report material climate risks, GHG emissions inventories, climate targets and goals, and the financial implications of physical and transition risks. However, following multiple legal challenges, the SEC voluntarily vacated these rules in February 2025. The regulatory landscape in this area remains uncertain, and new or revised climate disclosure requirements may be introduced in the future. If such rules are adopted and applied to us, our compliance costs — such as legal, accounting, and reporting expenses — could increase significantly, and the associated compliance efforts may divert management’s time and attention. In addition, the CVM approved Resolution No. 193/2023, which allows publicly held companies to voluntarily prepare and disclose sustainability-related financial reports in accordance with the International Sustainability Standards Board (“ISSB”) guidelines. According to CVM Resolution No. 193/2023, disclosure is mandatory for financial years beginning on or after January 1, 2026. We may be exposed to legal or regulatory action or claims as a result of future SEC climate disclosure requirements and existing CVM rules. Although we are in the process of assessing and adapting our internal procedures to comply with requirements , these risks could have a material adverse effect on our business, financial condition, results of operations and the prices of our securities. New expenditures resulting from new compliance with climate change regulations and from the prevention or correction of effects of extreme weather could have a material adverse effect on our results of operations. For more information, see “Item 4.B. Business Overview — Environmental Matters — Climate Change Regulations: Reduction of Greenhouse Gases (GHG) Emissions” and “Item 4.B. Business Overview—Power Consumption.” 32 Table of Contents Risks Relating to Our Privatization Our Privatization may still be subject to legal challenge, and the dispersed ownership structure resulting from our Privatization may impact our ability to efficiently approve certain transactions and could potentially delay critical decision-making processes, which may adversely affect our business and results of operations. Legal proceedings challenging our Privatization remain ongoing, as further described in “Item 8.A. Consolidated Financial Statements and Other Financial Information-Legal Proceedings.” Additional legal challenges or proceedings may also be filed in the future. Potential adverse rulings from judicial or administrative proceedings, if any, may have negative effects on our financial results and reputation. In addition, as a result of our Privatization, we no longer have a single controlling shareholder or group of controlling shareholders. This dispersed ownership structure, which has been in place since the consummation of our Privatization, presents ongoing governance challenges. The absence of a controlling shareholder may impact our ability to efficiently approve certain transactions and could potentially delay critical decision-making processes, which may adversely affect our business and results of operations. Risks Relating to Our Common Shares and ADSs We may issue additional common shares or enter into a merger, consolidation or other similar corporate transaction, which could dilute your interest in our common shares underlying the ADS. We may need to raise additional funds in the future, such as to finance capital expenditures or payments related to new concessions. These funds may be raised through private or public offerings of shares or securities convertible into shares issued by us. Under Brazilian Corporate Law and CVM regulations, public offerings of shares or convertible securities may be conducted without granting preemptive rights to our existing shareholders, including investors in the common shares underlying the ADSs. As a result, such issuances may dilute the interests of our then-existing investors. Dilution of your interest in the common shares underlying the ADSs may also occur if we enter into a merger, consolidation or any other corporate transaction with similar effects involving companies that we may acquire in the future. International judgments may not be enforceable when considering our directors or officers’ status of residency. All of the directors and officers identified in this annual report reside in Brazil. Neither we, nor our directors, officers, or the members of our audit committee have agreed to accept service of process in the United States. Additionally, substantially all of our directors’ and officers’ assets are located in Brazil. As a result, it may be difficult or impossible to effect service of process within the United States or in other jurisdictions outside Brazil upon such persons, to attach their assets, or to enforce civil liabilities or securities law judgments from U.S. courts or from courts of other jurisdictions against them or against us. We may not always be in a position to pay dividends or interest on shareholders’ equity and ADSs. Under Brazilian Corporate Law and our bylaws, we are required to distribute to our shareholders a mandatory minimum dividend equal to 25% of our net income after the allocation of legal reserves for the previous fiscal year. Other than the mandatory minimum dividend, we may retain profits in statutory reserves for investment purposes or in capital reserves. If we record a net loss or if our net income is insufficient to support dividend payments, including the mandatory minimum dividend, management may recommend using profit reserves to make such payments, after offsetting any net losses for the current or prior fiscal years. Losses for the current fiscal year must be absorbed in the following order: accrued profits, profit reserves and legal reserves. Even when we are able to declare dividends, management may still decide to postpone their payment or, in limited circumstances, not declare dividends at all. Certain reserves established under Brazilian Corporate Law cannot be used for dividend distributions. 33 Table of Contents In addition, the New Legal Framework for Basic Sanitation prohibits the distribution of profits and dividends by service providers that are in breach of the objectives and deadlines set out in their sanitation service agreements. The Concession Agreement for URAE-1 provides that, if it is determined that we are failing to meet the targets and schedules set forth in that agreement or in any other concession agreement, and provided that the applicable contractual procedures are followed, we may be prevented from paying dividends or interest on equity to our shareholders and ADS holders for as long as such breach continues. For more information, see “Item 8.A. Consolidated Financial Statements and Other Financial Information—Dividends and Dividend Policy.” Mandatory arbitration provisions in our bylaws may limit the ability of a holder of our ADRs to enforce liability under U.S. securities laws. Under our bylaws, any disputes among us, our shareholders, our directors, executive officers, members of the fiscal council, effective and alternates, and members of statutory and non-statutory committees, with respect to the Novo Mercado Listing Regulation, the Brazilian Corporate Law and Brazilian capital markets regulations will be resolved by arbitration conducted pursuant to the B3 Arbitration Rules in the Market Arbitration Chamber. Any disputes among shareholders and ADR holders, and any disputes between us and our shareholders and ADR holders, will also be submitted to arbitration. As a result, a court in the United States might require that a claim brought by an ADR holder predicated upon the U.S. securities laws be submitted to arbitration in accordance with our bylaws. In that event, a purchaser of ADSs would be effectively precluded from pursuing remedies under the U.S. securities laws in the U.S. courts. However, a court in the United States could allow claims predicated upon the U.S. securities laws brought by holders who purchased ADSs on the NYSE to be submitted to U.S. courts. For more information, see “Item 10.B. Additional Information—Memorandum and Articles of Association—Description of Common Shares—Redemption and Rights of Withdrawal.” A holder of our common shares and ADSs might be unable to exercise preemptive rights and tag-along rights with respect to the common shares. U.S. holders of common shares and ADSs may not be able to exercise the preemptive rights and tag-along rights relating to common shares unless a registration statement under the U.S. Securities Act of 1933, as amended (“Securities Act”), is effective with respect to those rights or an exemption from the registration requirements of the Securities Act is available. We are not obliged to file a registration statement with respect to our common shares relating to these rights, and we cannot assure you that we will file any such registration statement. Unless we file a registration statement or an exemption from registration is available — such as those provided under Rule 144A or Regulation S under the Securities Act, which may not be available to all holders — an ADS holder may receive only the net proceeds from the sale of their preemptive rights and tag-along rights or, if these rights cannot be sold, they will lapse, and the ADS holder will receive no value for them. Holders of our ADSs do not have the same voting rights as our shareholders. Holders of our ADSs do not have the same voting rights as holders of our shares. Holders of our ADSs are entitled to the contractual rights set forth for their benefit under the deposit agreements. ADS holders exercise voting rights by providing instructions to the depositary, as opposed to attending shareholders meetings or voting by other means available to shareholders. In practice, the ability of a holder of ADSs to instruct the depositary as to vote will depend on the timing and procedures for providing instructions to the depositary, either directly or through the holder's custodian and clearing system. ADS holders may not receive notice of shareholders' meetings sufficiently in advance to enable them to provide timely voting instructions to the depositary, which could result in their being unable to exercise their voting rights with respect to a given meeting. The deposit agreement also provides that if the depositary does not receive any instructions from a holder of ADSs, the ADS holder may be deemed to have given a discretionary proxy to a person designated by our company and the underlying shares may be voted by such person. However, we have chosen not to designate any person to exercise these deemed proxy rights with respect to any annual or special general meetings, and ADSs for which no specific voting instructions were received by the depositary were therefore not voted at that meeting. As a result, ADS holders who do not provide voting instructions and for whom no proxy is designated may have no influence over the outcome of votes on matters considered at shareholders’ meetings, including votes on material corporate transactions or governance matters. 34 Table of Contents Judgments of Brazilian courts with respect to our common shares are required to be payable only in reais. If proceedings are brought in the courts of Brazil seeking to enforce our obligations in respect of our common shares, we may not be required to discharge our obligations in a currency other than reais. Under Brazilian exchange control limitations, an obligation in Brazil to pay amounts denominated in a currency other than reais must only be satisfied in Brazilian currency at the exchange rate, as determined by the Central Bank of Brazil, in effect (1) on the date of actual payment, (2) on the date on which such judgment is rendered or (3) on the date on which collection or enforcement proceedings are commenced. The then prevailing exchange rate may not provide non-Brazilian investors with full compensation for any claim arising out of or related to our obligations under the common shares or the common shares represented by ADSs.
A. History and Development of the Company Overview We were incorporated as a public, mixed capital company of unlimited duration on September 6, 1973, under the laws of the Federative Republic of Brazil. In 1994, we were registered with the CVM as a publicly held company and are…
A. History and Development of the Company Overview We were incorporated as a public, mixed capital company of unlimited duration on September 6, 1973, under the laws of the Federative Republic of Brazil. In 1994, we were registered with the CVM as a publicly held company and are therefore subject to CVM’s rules, including those relating to the periodic disclosure of extraordinary facts or relevant events. Our common shares have been listed on the B3 under the ticker “SBSP3” since June 4, 1997. In 2002, we joined the Novo Mercado segment of the B3 and registered our common shares with the Securities and Exchange Commission (“SEC”) and started trading our shares in the form of ADR - level III on the New York Stock Exchange (“NYSE”) under the ticker “SBS.” Until June 2024, the State of São Paulo owned a majority of our voting common shares. In July 2024, we were privatized, and the State of São Paulo ceased to be our controlling shareholder. As part of our Privatization, Equatorial S.A. became a reference shareholder holding 15% of our voting capital. In accordance with our amended bylaws, we no longer have a controlling shareholder: our bylaws prohibit any shareholder or group of shareholders from exercising votes over 30% of our issued and outstanding voting capital or from entering into shareholders’ agreements for the exercise of voting rights in excess of 30% of our issued and outstanding voting capital. We are subject to Brazilian Corporate Law and to any and all laws and regulations that govern Brazilian private legal entities. We are registered with the Commercial Registry of the State of São Paulo (Junta Comercial do Estado de São Paulo) under registration number NIRE 35300016831. Our principal executive offices are located at Rua Costa Carvalho, 300, Zip Code 05429-900 São Paulo, SP, Brazil. Our telephone number is +55 11 3388-8110. Our agent for service of process in the United States is CT Corporation System, with offices at 818 West Seventh Street - Team 1, Los Angeles, CA 90017. As of December 31, 2025, we provided water and sewage services to numerous residential, commercial and industrial consumers, as well as various public entities, in 375 municipalities in the State of São Paulo, including the city of São Paulo, under concession agreements, with 371 covered by URAE 1 until 2060. Since December 2023, we operate water and sewage services in Olímpia, a municipality located in the interior of the State of São Paulo, through our wholly-owned subsidiary Sabesp Olimpia S.A. This new contract with the municipality of Olímpia is the first bidding process won without being part of a consortium under the New Legal Framework for Basic Sanitation. In May 2025, we exercised our preemptive rights to acquire the remaining 70% equity interests in Águas de Andradina S.A. and Águas de Castilho S.A., which were previously held by Iguá Saneamento S.A. (“Iguá”). Following regulatory review, on July 1, 2025, the Superintendence of Brazil’s Administrative Council for Economic Defense (“CADE”) approved the transaction without restrictions. 35 Table of Contents However, the transaction is still subject to the fulfillment of customary conditions precedent, and therefore the closing has not yet occurred. As a result, we will only consolidate 100% ownership of both concessions after the closing, once all pending conditions have been implemented. We believe that this transaction will strengthen our operational footprint and service delivery capacity in the State of São Paulo. In addition, we maintain a strategic partnership in SESAMM – Serviços de Saneamento de Mogi Mirim S.A., a sewage-only concession, further broadening the scope of our sanitation services. In the basic sanitation sector, we are non-controlling shareholders in two special purpose companies: Aquapolo Ambiental S.A., supplying industrial reclaimed water to the Capuava Petrochemical Complex since 2012 and Attend Ambiental S.A., providing non-domestic wastewater treatment services in the São Paulo metropolitan area since 2014. We also participate in the electric power generation sector through minority partnerships. Through Paulista Geradora de Energia (“PGE”), we leverage the hydraulic potential of the Cantareira System, generating and selling 4.1 MW from the PGE Guaraú plant (operational since March 2023) and 2.9 MW from the PGE Cascata plant (operational since April 2024). Since October 2022, we have held a 49% equity interest in Cantareira SP Energia S.A., a company organized for the development, production and commercialization of photovoltaic energy. Cantareira SP Energia S.A. is also authorized to engage in the commercialization, purchase and sale of energy; the lease, lending for use (comodato) or lease (arrendamento) of assets owned by it or by third parties; the operation and maintenance of power generation facilities; and the acquisition of equity interests in other companies. Since December 2022, we have held a 20% equity stake in Barueri Energia Renovável S.A., a special purpose company designed to process municipal solid waste from the municipality of Barueri and surrounding municipalities into energy. The plant is expected to commence commercial operations in February 2027. In addition, we established SPE Infranext Soluções e Pavimentação S.A., with the purpose of operating in the cold asphalt commercialization and related products segment. However, the entity is currently in its preoperational phase. Recent Developments US$1,500 Million Loan Agreement and US$1,350 Million Blue Bond Issuance On January 27, 2026, we entered into a loan agreement with the Inter-American Investment Corporation, consisting of (i) a senior unsecured loan in an aggregate principal amount of US$150.0 million, issued in a single tranche and maturing in 2038 (the “Term Loan A”), and (ii) a blue unsecured loan in an aggregate principal amount of US$1,350.0 million, issued in two tranches maturing in 2031 and 2036, respectively (the “Term Loan B” and, together with the Term Loan A, the “Loans”). The Term Loan B serves as the underlying asset for the issuance of two series of blue senior secured notes by Nova Securitisation S.À.R.L, including a US$850.0 million in aggregate principal amount of 5.750% blue senior secured notes due 2031, and a US$500.0 million in aggregate principal amount of 6.500% blue senior secured notes due 2036 (“Blue Bonds”). The Blue Bonds are listed on the Euro MTF Market of the Luxembourg Stock Exchange. The Blue Bonds were offered solely to qualified institutional buyers in the United States under Rule 144A and to eligible purchasers in other jurisdictions (excluding Brazil and the U.S.) under Regulation S of the U.S. Securities Act of 1933, as amended. The offering and sale of the Blue Bond were completed on February 3, 2026. We intend to use the net proceeds from the Loans and the Blue Bonds for projects supporting our universalization targets for basic sanitation in the Brazilian state of São Paulo, including construction and upgrading of sewage treatment facilities and expansion of collection systems. Offering and Sale of Debentures On February 10, 2026, we completed our 38th issuance of simple, non-convertible, unsecured debentures, with an aggregate principal amount of R$6,292.1 million, in five series, including: (i) a first series with an aggregate principal amount of R$1,635.7 million, bearing interest at the IPCA index plus 6.2907% p.a., maturing in February 2036; (ii) a second series with an aggregate principal amount of R$1,364.7 million, bearing interest at the IPCA index plus 6.3507% p.a., maturing in February 2038; (iii) a third series with an aggregate principal amount of R$1,291.7 million, bearing interest at the IPCA index plus 6.2467% p.a., maturing in February 2041; (iv) a fourth series with an aggregate principal amount of R$1,000.0 million, bearing interest at CDI index plus a spread of 0.64% p.a.; and (v) a fifth series with an aggregate principal amount of R$1,000.0 million, bearing interest at CDI index plus a spread of 0.72% p.p. 36 Table of Contents These debentures were offered and sold in Brazil exclusively to professional investors (investidores profissionais), as defined under applicable CVM regulations. We intend to use the net proceeds from this offering and sale of debentures for investments related to the universalization and working capital. EMAE Acquisition On October 4, 2025, we entered into certain share purchase agreements, whereby we agreed to purchase: (i) 74.9% of the common shares of Phoenix Água e Energia S.A. of EMAE – Empresa Metropolitana de Águas e Energia S.A. (“EMAE”), held by Vórtx Distribuidora de Títulos e Valores Mobiliários, Ltda., in its capacity as trustee (agente fiduciário) for the holders of certain debentures, subject to certain conditions precedents (“EMAE Control Acquisition”); and (ii) 66.8% of the preferred shares of EMAE, held by Centrais Elétricas Brasileiras S.A. – Eletrobrás (“Eletrobrás”), subject to certain conditions precedent (“EMAE Preferred Shares Acquisition” and, together with the EMAE Control Acquisition, the “EMAE Acquisition”). On January 21, 2026, we completed the EMAE Control Acquisition at a price of R$62.00 per common share, for an aggregate purchase price of R$682.6 million, thereby becoming the controlling shareholder of EMAE. As a result, on February 2, 2026, we filed with the CVM a request for registration of a mandatory tender offer (oferta pública de aquisição de ações) to acquire up to all free float common shares of EMAE, at a price of 49.47 per common share (subject to adjustments based on the Selic rate). ("Tender Offer for the Sale of Control") In addition, on January 28, 2026, we completed the EMAE Preferred Shares Acquisition, at a price per preferred share of R$32.07, totaling an aggregate amount of R$476.5 million, and became holders of 70.1% of the total share capital of EMAE. In addition, on March 12, 2026, we entered into certain quota purchase and sale agreement with África Fundo de Investimento Multimercado Responsabilidade Limitada for the acquisition of 100% of the quotas of Oceania Fundo de Investimento em Ações (“Oceania”), for a total purchase price of R$171.6 million, paid in cash on March 13, 2026. As of the date of this annual report, we hold 79,31% of EMAE's the total share capital and 98.04% of its voting share capital, including the stake in the Oceania acquired on March 12, 2026 as mentioned above. As a result of the increased ownership due the acquisition of the quotas of Oceania, Sabesp requested, on April 24, 2026, CVM approval for the unification of the Tender Offer for the Sale of Control with an tender offer for increase of shareholding (collectively, the “Unified Tender Offer”) to acquire up to all free float common shares of EMAE, at a price of R$61.83 per common share (subject to adjustments based on the Selic rate). EMAE Acquisition represents a strategic milestone for us, delivering benefits on two complementary fronts: • Water security. The integration of the Guarapiranga and Billings systems will provide greater flexibility in water resource management within the São Paulo Metropolitan Region, enhancing water supply security and enabling multiple uses of these water sources; and • Power Assets. EMAE’s portfolio of power generation assets is supported by long-term, inflation-indexed revenue contracts, providing stable cash flows and contributing to financial stability and sustainable value creation. 37 Table of Contents Potential Merger of Shares of EMAE On April 24, 2026, we announced that our and EMAE's respective managements are evaluating the feasibility of a merger of shares of EMAE, pursuant to Article 252 of Brazilian Corporate Law (the “Share Merger”). The feasibility study for the Share Merger includes an analysis of the authorizations, conditions and procedures required for its implementation, as well as the establishment of independent committees to negotiate the share exchange ratio, in accordance with the guidance set out in CVM Guidance Opinion No. 35/2008. If the Share Merger is approved by the management bodies and shareholders of both companies, EMAE will be converted into our wholly owned subsidiary and EMAE’s shareholders will receive shares issued by us in exchange, in accordance with the share exchange ratio to be negotiated by the independent committees. The proposed Share Merger is intended to simplify and optimize the corporate structure of the companies by consolidating their shareholder bases into a single company and reducing operational costs. Acquisition of Sanessol On January 27, 2026, we entered into certain share purchase agreement with Iguá for the acquisition of common shares representing 90% of the capital stock of Saneamento de Mirassol – Sanessol S.A. (“Sanessol”). This acquisition is aligned with our strategy to expand and consolidate our operations in the sanitation sector in Brazil, consistent with our focus on the provision of public water supply and sewage services. The closing of the transaction is subject to the satisfaction of conditions precedent that are customary for this type of transaction. Sanessol’s corporate purpose is the provision of public water and sewage services, and it is the holder of the concession agreement for the operation of the public water supply and sewage services in the municipality of Mirassol, in the State of São Paulo, serving a population of approximately 65,000 inhabitants. Capital Increase On March 16, 2026, our Board of Directors approved an increase in our share capital within the authorized capital limit, by capitalizing profit reserves in the amount of R$169.2 million, through the issuance of 1,132,937 new registered, book-entry common shares with no par value. These new shares were allocated to shareholders of record as of the close of business on March 19, 2026, at a ratio of 0.00160980322 new common shares for each common share held. Prior to this capital increase, our share capital amounted to R$21.2 billion. As a result of the approved transaction, our share capital increased to R$21.4 billion, currently divided into 704,906,805 common shares and one special class preferred share. Approval of Our Share Split On April 28, 2026, our shareholders approved the split all of our outstanding common shares at a ratio of 1:5, so that each one common share will be represented by five common shares, without any change to our share capital (the “Share Split”). The Share Split will not affect our ADR program or the ratio between our ADRs and our common shares. However, following the Share Split, each one ADR will be represented by five ADRs. The Share Split will not result in any change to our shareholders’ proportional ownership interests in our share capital. The common shares resulting from the Share Split will grant their holders the same rights currently attributed to our existing common shares, including with respect to the receipt of dividends, interest on equity and any other distributions that may be approved by us. The implementation of our Share Split is expected to occur on or about May 4, 2026. As a result of the Share Split, the weighted average number of shares considered for the calculation of basic and diluted earning per share presented in our 2025 Consolidated Financial Statements was retrospectively adjusted for all periods presented therein, in accordance with IAS 33. For additional information, see Note 33 to the 2025 Consolidated Financial Statements included elsewhere in this annual report. Our Strategy Our strategy is to provide people a better future by delivering essential services with excellence and a firm commitment to public health and the environment. Our aspiration is to become a global leader in basic sanitation, driving a more sustainable society and generating robust, long-lasting value for our shareholders. To achieve this aspiration, we have defined the following strategic priorities: • Universalization under the new concession agreement for URAE-1 • Customer satisfaction • Stakeholder engagement and support • Water resource sustainability and product quality • Community sustainability • Innovation and digital transformation 38 Table of Contents • Business efficiency • Excellence in regulatory management • Employee development • New business development These strategic priorities define the avenues through which we execute our corporate strategy, guiding resource allocation, capability building, and operating discipline to deliver sustainable value for society and our shareholders. Corporate Organization Following our Privatization and the changes to our bylaws, we updated our governance structure. Key changes included reorganizing departmental responsibilities of each executive officer and creating new structures to optimize our growth and adapt to recent regulatory changes in the sanitation sector. Our executive management currently comprises eleven officers with responsibilities allocated by the Board of Directors and our by-laws. This includes overseeing compliance and risk management, led by a statutory officer appointed by the Board, as well as administrative oversight of internal audit. Statutory Executive Officers: • Chief Executive Officer; • Chief Financial and Investor Relations Officer; • Chief Engineering Officer; • Chief Operation and Maintenance Officer; • Chief Customer and Technology Officer; • Chief Regulation and Power Procurement Officer; and • Chief Legal Officer. Non-statutory Executive Officers: • Chief People Officer; • Chief Corporate Services Officer; • Chief Institutional Relations and Sustainability Officer; and • Chief New Business and Projects Officer. Capital Expenditure Program Our capital expenditure program aims to enhance and expand our water and sewage system, striving for universal sanitation services in the municipalities we operate. It focuses on ensuring water security, meeting the increased demand for treated water in the State of São Paulo, improving operating efficiency and reducing environmental impacts. To achieve this, our investment plan is structured around four pillars: • Expansion Capital Expenditures: focused on meeting the goals of universalization of water supply, sewage and sewage treatment. • Renewal Capital Expenditures: intended for the maintenance of our existing assets. 39 Table of Contents • Operational Efficiency Capital Expenditures: aimed at increasing efficiency, automation and reducing water losses. • Indirect Capital Expenditures: directed to administrative investments and to support our infrastructure. As of the date of this annual report, we anticipate investments of approximately R$70 billion from 2024 to 2029, financed by own resources, loans, and long-term financing. We invested R$15.2 billion, R$6.9 billion and R$6.3 billion in the years ended December 31, 2025, 2024 and 2023, respectively. The following table presents the number of incremental connections achieved in 2025, as well as the targets established for 2026, relating to water coverage, sewage coverage, and sewage treatment. Incremental Connections 2024-2025 (in units) 2026 (in units) Water coverage 435,844 860,860 Sewage coverage 588,427 1,122,272 Sewage treatment 1,027,620 2,121,043 Our capital expenditure program from 2025 through 2029 will continue to focus on achieving our targets by making regular investments to maintain and expand our infrastructure and to reduce water losses in the 375 municipalities we served as of December 31, 2025. Main Focus of Our Capital Expenditure Program The following is a description of the main focuses of our capital expenditure program. Investments in water Expansion of Water Systems: Investments aimed at expanding the supply infrastructure in urbanized areas of the municipalities, in rural communities and in vulnerable communities and informal areas, ensuring the availability of safe and sustainable drinking water to keep up with growths in population, urban development and the growing existing demand, including the implementation of networks, formalization of connections and alternative solutions adapted to the local reality and also new distribution networks, reservoirs, pipelines and reinforcements in existing systems or, for rural areas, well drilling, implementation of simplified systems and decentralized supply technologies. Water Resilience: Continuity of our actions to ensure water security in face of extreme weather events, prolonged droughts, and increased demand. These investments include diversification of water sources, interconnection of systems, expansion of reservoirs and modernization of operational processes. Vegetative Growth: Gradual expansion of our supply infrastructure to meet the increase in population and the verticalization of municipalities we cover. These investments provide for reinforcements in production and distribution of water, ensuring continuity and quality of supply. Investments in sewage Expansion of Sewage Systems (Coverage and Treatment): Investments focused on at expanding the sanitary sewage infrastructure in vulnerable communities and informal areas to ensure viable technical solutions that are appropriate to the local reality, as well as in the expansion of collection networks, connection of new economies and expansion of the installed capacity of sewage treatment plants in urban areas of the municipalities, aiming to serve new residences and promote the reduction of the environmental pollution load of the receiving bodies. For rural areas, these investments are aimed at bringing sewage collection and treatment to rural communities, using appropriate technologies such as septic tanks and compact treatment stations. 40 Table of Contents Vegetative Growth: Expansion of sewage networks and treatment capacity to keep up with the demographic growth of cities. These investments provide for new collection networks, interceptors and modernization of treatment plants to ensure the universalization of sanitation. Loss Reduction Implementation of measures to reduce infrastructure damages or losses (including leaks, pipe ruptures, etc.) and losses arising from consumer fraud (under-metering and other methods of tampering with our measurement devices) in the water distribution system. Our actions include the sectorization of distribution networks, therefore segmenting extensive networks into smaller sections, enhancing the management and operational oversight of the distribution system, replacement of old pipes, replacement of water meters, modernization of measurement methods and combating irregular sewage or water networks. Automation Digitalization and modernization of our operating systems in order to increase our efficiency and reduce costs. Our actions include using telemetry, smart sensors, remote control of pumping stations and implementation of operational control centers to optimize the management of sanitary supply and sewage. Public Information The SEC maintains an internet site (www.sec.gov) that contains reports, proxy and information statements, and other information regarding issuers that file electronically with the SEC, including us. See “Item 10. Additional Information—H. Documents on Display.” Our website is ri.sabesp.com.br/en. Information contained on or obtainable through our website is not incorporated into, and does not constitute a part of, this annual report. B. Business Overview Our Operations As of December 31, 2025, we provided water and sewage services to a broad range of residential, commercial, industrial and governmental customers in 375 of the 645 municipalities in the State of São Paulo, including the city of São Paulo, under concession agreements, with 371 covered by URAE 1 until 2060. These 371 municipalities accounted for 99.8% of our gross operating revenues from sanitation services (excluding revenues relating to the construction of concession infrastructure). Four municipalities (Miguelópolis, Quintana, Nova Guataporanga and Olímpia) continue under their pre-Privatization individual contracts. These concession agreements will expire between 2027 and 2053 and accounted for 0.2% of our gross operating revenues from sanitation services (excluding revenues relating to the construction of concession infrastructure) as of December 31, 2025. We also supplied water and sewage treatment services on a wholesale basis to two municipalities in the São Paulo metropolitan region (Mogi das Cruzes and São Caetano do Sul). For more information on these agreements, see Note 10 to our 2025 Consolidated Financial Statements. As of December 31, 2025, our operating revenue amounted to R$38,092.1 million and profit for the period amounted to R$8,462.1 million. Our total assets amounted to R$104,202.8 million and our total equity amounted to R$42,401.1 million. We provided water services to approximately 29.9 million people, and sewage services to approximately 27.0 million people in the State of São Paulo. For more information on laws and regulations related to our concession operations, see “—Government Regulations Applicable to our Contracts.” 41 Table of Contents Description of Our Activities Our corporate purpose is to provide basic sanitation services aimed at achieving the universalization of basic sanitation in the State of São Paulo. Our primary activities include water supply, sanitary sewage services, urban rainwater management and drainage services, urban cleaning services, and solid waste management services. Our related activities include the planning, operation, and maintenance of systems for the production, storage, conservation and commercialization of energy, as well as the commercialization of services, products, benefits and rights that directly or indirectly arise from our assets, operations and activities. Additionally, at the General Shareholders’ Meeting held on April 29, 2025, our shareholders approved an amendment to our bylaws to include the generation of electricity for self-consumption, with the option to sell any surplus. This amendment is intended to enhance the efficiency of our basic sanitation services and optimize the use of our assets. For more information, see “—Government Regulations Applicable to Our Contracts—ARSESP.” We set forth below a description of our activities. Water Operations Our supply of water to our customers generally involves water extraction from various sources, subsequent treatment and distribution to our customers’ premises. For the year ended December 31, 2025, we produced approximately 3,227.3 million cubic meters of water. The following table sets forth the volume of water that we produced and invoiced for the periods indicated: Year ended December 31, 2025 2024 2023 (in millions of cubic meters) Produced: Total 3,227.3 3,086.3 2,985.2 Invoiced: Residential 1,968.1 1,970.7 1,918.0 Commercial 195.5 191.3 189.2 Industrial 34.2 36.3 35.4 Public 55.2 51.1 47.1 Total Retail 2,253.0 2,249.7 2,189.7 Wholesale (1) 34.9 49.5 46.5 Total 2,287.9 2,299.3 2,236.2 (1) Wholesale includes volumes of reuse water and non-domestic sewage. Seasonality Although seasonality does not affect our results in a significant way, in general, we observe higher water demand during the summer and lower water demand during the winter. The summer coincides with the rainy season, while the winter corresponds to the dry season. The demand in the coastal region is increased by tourism, with the greatest demand occurring during the Brazilian summer holiday months. Water Resources Our water withdrawals are limited to authorized volumes by SP Águas, with federal approval from the National Water and Sanitation Agency (Agência Nacional de Águas e Saneamento Básico - ANA) required for basins crossing state lines. We primarily source our water supply from rivers and reservoirs, with a small portion from groundwater. Our reservoirs are filled by impounding and/or diverting river flows. For more information on water usage regulation, see “—Environmental Matters—Water Usage.” As of December 31, 2025, we operated eleven water systems in the São Paulo metropolitan region. The total capacity of the water sources available for treatment in this area is 1.945 million m3. The average monthly production was 70.7 m3/s, with the Cantareira, Guarapiranga and Alto Tietê systems providing approximately 80% of the water distributed. The Cantareira system alone supplied 41.2% of region’s water. For more information, see “Item 3.D. Risk Factors—Risks Relating to Environmental Matters and Physical and Climate Transition Risks— Droughts, such as the 2014 – 2015 water crisis, can cause a material impact on consumption habits and, consequently, on our business, financial condition or results of operations.” 42 Table of Contents We participate in the decentralized and integrated management of water resources established by the National Policy on Water Resources. We are represented by our employees in all River Basin Committees in the State of São Paulo. The following table sets forth the water production systems from which we produce water for the São Paulo metropolitan region: Year ended December 31, 2025 2024 2023 (in cubic meters per second) Water production system: Cantareira 29.1 28.7 26.5 Guarapiranga 13.4 12.4 13.1 Alto Tietê 12.6 12.9 12.4 Rio Claro 3.3 4.7 3.5 Rio Grande (Billings reservoir) 5.1 3.0 4.6 Alto Cotia 1.0 1.0 1.0 Ribeirão da Estiva 0.0 0.1 0.1 São Lourenço 5.2 4.0 3.3 Cabuçu and Tanque Grande (Guarulhos) 0.2 0.3 0.3 Embú-Guaçu 0.1 0.1 - Total 70.7 67.2 64.8 Water Treatment As of the date of this annual report, we operate 214 water treatment facilities and 690 simplified water treatment facilities, where all water is treated before being distributed by our water supply network. The type of treatment used depends on the nature of the source and quality of the untreated water. For example, water abstracted from rivers requires more treatment than water withdrawn from groundwater sources. All of the water we treat receives fluoridation. Water Distribution We distribute water through our networks of water pipes and water transmission lines. Storage tanks and pumping stations regulate the volume of water flowing through the networks in order to maintain adequate pressure and continuous water supply. The following table sets forth the number of connections in our network as of the dates indicated: As of December 31, 2025 2024 2023 Number of connections (in thousands)(1) 10,624 10,455 10,286 (1) Includes the connections from URAE-1, Miguelópolis, Nova Guataporanga, Quintana, and Olímpia. Water Loss Water loss is calculated as the difference between the volume of water produced and the volume of water measured by the water meters installed in our customers’ properties. Water losses are divided into: apparent (non-physical) losses, which result mainly from inaccurate water meters, fraud and registration errors, and real (physical) water losses, resulting from leaks in the distribution network and overflows in tanks. 43 Table of Contents We exclude from the calculations of water loss: (i) water discharged for periodic maintenance of water distribution lines and cleaning of water storage tanks; (ii) water supplied for municipal uses, such as fighting fires; and (iii) estimated water loss related to the supply of water to urban areas occupied by low-income populations in irregular areas (favelas). Water loss decreased from 34.6% as of December 31, 2012 to 30.5% as of December 31, 2025, as measured by the total distribution losses index (Índice de Perdas na Distribuição, or IPM). In respect of the Concession Agreement for URAE-1, we have met the water loss reduction targets established for 323 municipalities for 2025, as set out in Annex II of the Concession Agreement for URAE-1. Water Quality We believe that we supply high quality treated water that is consistent with the standards set by Brazilian law, which establishes water quality standards (Annex XX of Consolidation Ordinance No. 5 - amended by Ordinance No. 888 of May 2021), requiring us to comply with significant regulatory obligations. In general, the State of São Paulo has excellent water quality. However, there are anthropogenic and natural factors that can cause changes in water quality. Currently, we treat this water to make it potable and we are also investing in improvements in our water transmission lines and our treatment systems to ensure the quality and availability of water for the coming years. Water quality is monitored at all stages of the distribution and is carried out by our quality control laboratories distributed in various regions of the State of São Paulo, equipped with modern analytical equipment and qualified professionals. Our laboratories are ABNT NBR ISO IEC 17025 accredited, awarded by INMETRO. Quality control of the chemicals used in water treatment is also performed to verify compliance with the specifications established in national and international recommendations, aiming to ensure the absence of toxic substances harmful to human health. As of the date of this annual report, we believe that there are no material instances where our standards are not being met. Fluoridation As required by Brazilian law, we add fluoride to the water at our treatment facilities prior to its distribution into the water supply network. Fluoridation primarily consists of adding fluorosilicic acid to water at between 0.6 mg/L and 0.8 mg/L to assist in the prevention of tooth decay among the population. Sewage Operations We are responsible for the collection, removal, treatment and final disposal of sewage. We installed 197.3 thousand, 191.4 thousand and 226.5 thousand new sewage connections in the years ended December 31, 2025, 2024 and 2023, respectively. Sewage System The purpose of our sewage system is to collect and treat sewage and to adequately dispose of the treated sewage. The following table sets forth the total number of sewage connections in our network for the periods indicated: As of December 31, 2025 2024 2023 Sewage connections (in thousands) 9,160 8,932 8,776 Our sewage system is generally designed to operate by gravitational flow, with pumping stations used where necessary, employing cast iron sewage lines. 44 Table of Contents The public sewage system is designed to handle both household and portion non-domestic effluents (such as industrial sewage) which require compliance with specific legal standards to protect the sewage collection and treatment systems, the health and safety of operators and the environment. Non-domestic effluents must meet standards set by State Decree No. 8,468/1976, and may require pretreatment. We conduct acceptance studies to ensure compliance and capacity before permitting discharge, formalizing conditions in agreements with effluent producer. Non-compliance can result in penalties, with CETESB notified for severe breaches. Effluents from our treatment facilities must comply with limitation guidelines for discharge into receiving water bodies, ensuring water quality is not compromised, as established by State Law No. 997/1976 regulated by State Decree No. 8,468/1976 and the National Environmental Council (Conselho Nacional de Meio Ambiente – “CONAMA”) Resolution No. 357/2005, as amended by CONAMA Resolution No. 430/2011 which establishes conditions and standards for effluent discharge. Sewage Treatment and Disposal As of December 31, 2025, we operate 641 sewage treatment facilities, including eight ocean outfalls, with an installed capacity of approximately 61.4 cubic meters of sewage per second. In the São Paulo metropolitan region, the treatment process used by most treatment facilities is the activated sludge process. In other regions, sewage treatment varies according to the particularities of each area. In the interior region of São Paulo State, treatment consists largely of stabilization ponds. The majority of sewage collected in the coastal region receives treatment and disinfection and is then discharged into rivers and also into the Atlantic Ocean through our ocean outfalls, in accordance with applicable legislation. In this regard, we are a party to legal proceedings related to environmental matters. For more information, see “Item 8.A. Consolidated Financial Statements and Other Financial Information—Legal Proceedings.” In addition, our capital expenditure program includes projects to increase the amount of sewage that we treat. For more information, see “Item 4.A. History and Development of the Company—Capital Expenditure Program” and “Item 4.B. Business Overview—Environmental Matters—Environmental Regulation—Sewage Requirements.” Sludge Disposal The generation of sludge is inherent in the sanitation cycle. We use various methods, such as filter presses, belt filter presses, drying beds and centrifugation machines, to dewater sludge, reducing its volume and final disposal costs. We are exploring innovative technological sludge disposal methods. Since 2018, we have produced an agricultural organic fertilizer, Sabesfértil, made by bio-drying sewage sludge, and which was approved for sale by the Ministry of Agriculture. Other projects include a plasma system which uses specialized technology to transform sludge into an inert solid vitreous product to be re-used in construction work, and a sludge dryer that uses sunlight and automated processes. In 2025, we conducted operational tests with a pilot thermal sludge treatment plant using pyrolysis to evaluate byproducts such as biochar, pyrolytic oil and syngas. We are implementing a thermal sludge drying system that uses indirect dryers fed exclusively with biogas generated at the wastewater treatment plant itself. The aim is to convert the sludge into material for agricultural input, reducing the need for final disposal and contributing to the circular economy and the value add of by-products. Sludge disposal must comply with State and Federal law requirements. In the State of São Paulo, CETESB has reissued the technical standard P4,230, second edition, of May 2021, which addresses the “application of sludge from biological treatment systems of sanitary liquid effluents in soil – guidelines and criteria for the project and operation.” This allows sludge use for soil recovery, creating new opportunities in the countryside of the State of São Paulo. 45 Table of Contents Principal Markets in Which We Operate We provide water and sewage services directly to a large number of residential, commercial and industrial consumers, as well as to a variety of public entities. Our Concession Agreements The Concession Agreement for URAE-1 The Concession Agreement for URAE-1 provides for significant changes to our economic-regulatory model. Under the Concession Agreement for URAE-1 we provide services for water and sewage to 371 municipalities in the state of São Paulo. The Concession Agreement for URAE-1 also provides for specific targets such as the Universalization Target. Under the Concession Agreement for URAE-1, the tariff adjustment index (Índice de Reajuste Tarifário - IRT) also provides for significant changes to our Tariff Structure, as defined below. We cannot guarantee that these changes will not have a significant financial impact on us. The main provisions of the Concession Agreement for URAE-1 are as follows: • Adoption of a retroactive methodology for tariff recognition of investments (the tariff calculation will only incorporate the investments already made by us). • Changes of the tariff review equation for the first two cycles of the Concession Agreement for URAE-1, with the inclusion of the Factor U and updates to the regulatory asset base (“RAB”) and market achieved in the reference year. In the first two cycles, the RAB will be updated annually. Additionally, similar to the previous model, inflation, Factor Q and Factor X are considered. • The Factor U will be applied annually as a reducing factor of up to 10% as part of the tariff readjustments. • The WACC will be applied before taxes. • New concepts: the “application tariff” (for service users) and “equilibrium tariff” (to be received by us). The difference will be compensated mainly by FAUSP (created by State Law No. 17,853/2023), which provides resources for basic sanitation actions, including those aimed at tariff moderation in the sector, in order to achieve and the universalization targets for 2029, as set out by State Law No. 17,853/2023. • On a monthly basis, we must calculate the difference between the (i) regulatory revenue effectively received from the market, by applying the application tariff, and the (ii) regulatory revenue, by applying the equilibrium tariff. • The valuation of new investments will be made using the depreciated replacement cost (DRC) method. • The remuneration of regulatory working capital will deduct the earnings from financial investments. • The failure to implement regulatory accounting by 2026 will result in a penalty of 100% of accessory revenues being allocated to tariff moderation and a greater sharing of efficiency with tariff moderation already in the second tariff cycle of the Concession Agreement for URAE-1. • The new model stipulates that we will be entitled to integrate a portion of the efficiency gains they achieve over multiple cycles. • Several parts of the methodology need to be regulated by ARSESP. As of the date of this annual report, we are a party to (i) the Concession Agreement for URAE-1; and (ii) four individual contracts entered into with the municipalities of Miguelópolis, Nova Guataporanga, Quintana, which chose not to join the Concession Agreement for URAE-1, and Olímpia. 46 Table of Contents Competition Competition primarily arises through mandatory public tenders for new or renewed sanitation concessions under Brazil’s updated legal framework (Law No. 14,026/2020), which intensified bidding between state-owned and private operators. Within URAE-1, we serve 371 municipalities under a regional concession; outside that perimeter or in non-adherent municipalities, tenders may occur and we may face competitors or decide to bid ourselves, including beyond State of São Paulo. Additionally, we may participate in competition for other concessions for the provision of water and sewage services in municipalities, metropolitan regions, microregions and regional units outside of the State of São Paulo. Use of Alternative Water Sources In recent years, we have experienced an increasing level of use of alternative sources, including residential condominiums and non-residential, industrial customers. One reason for the use of alternative water sources is because some users require water with different technical specifications than the water made available to the public. This trend has increased in recent years, especially since the 2014-2015 water crisis, when non-residential customers and residential condominiums sought independent solutions to supply water and dispose of non-residential, commercial and industrial sludge in the São Paulo metropolitan region. Private companies offer stand-alone water treatment solutions inside the facilities of their customers. In addition, the treatment of non-residential, commercial and industrial sewage treatment in the São Paulo metropolitan region has increased in recent years as private companies have started to offer customized solutions for customers’ facilities. Competition for new municipalities As described in our bylaws, we may operate through subsidiaries in any part of Brazil or abroad to provide sanitation services. We believe this makes us a potential competitor for other sanitation companies, both Brazilian and foreign. The New Legal Framework for Basic Sanitation imposes mandatory bidding processes for municipalities to hire companies providing basic sanitation services. This opened up a new business environment in which state-owned and private companies could compete. Participating in a bidding process is now the only method of maintaining and/or expanding our market share, whether in the State of São Paulo or in other states. Billing Procedures The billing and payment procedure for our water and sewage services is largely the same for all customer categories. Under the current tariff structure, water and sewage bills are based on water consumption determined by monthly meter readings. Sewage charges are included in the water bill and are based on the water meter reading. Meter readings for billing purposes are taken by our team and/or third parties using a mobile application, with simultaneous printing and delivery of the bill to the customer or, if the customer prefers, the bill can be sent digitally (by email, for example) or by mail to an address of the customer’s choice. Water and sewage bills can be paid online, via PIX (Brazil’s instant payment system), through banking correspondents, or by debit or credit card. Customers must pay their water and sewage bills by the due date to avoid late payment fees and interest. Customers with unpaid bills are subject to administrative collection procedures, water supply disconnection, and legal collection proceedings. The improvement of our collections process was one of the principal drivers of increased EBITDA and cash generation in 2025. We more than tripled the volume of cutoff and collection orders, with all teams equipped with POS (Point of Sale) terminals, enabling customers to make payments on-site to avoid water supply disconnection. 47 Table of Contents We believe we were the first utility in the world to implement payment via WhatsApp using PIX and credit card, including installment payments, and we believe we were the first company in Brazil to implement Automatic PIX (Brazil’s automatic recurring instant payment feature), reflecting our commitment to innovation in the adoption of technology. Furthermore, we intensified the reporting of defaulting customers to credit bureaus, the negotiation of debts with large debtors, and the holding of Debt Negotiation Fairs (“Large credit campaigns”). With these initiatives, we increased our collection rate from 98.1% to 101.7% (a collection rate exceeding 100% reflects the recovery of amounts billed in prior periods), resulting in an increase in cash of approximately R$900 million in 2025, and a reduction in our allowance for doubtful accounts (PECLD) of approximately R$450 million, with a corresponding positive impact on EBITDA. With respect to commercial losses (water fraud, theft, and underreporting of sewage), we launched a Commercial Loss Reduction Program in 2025 to decrease losses through strategies that ensure operational efficiency and financial effectiveness. The actions prioritize optimizing the selection of targets for inspections, increasing revenue, and promptly regularizing losses that impact billing. In 2025, we centralized the administrative activities of the process, promoting standardization and strengthening management: • In 2025, approximately 52,559 irregularities were identified, more than double the number identified in 2024, with approximately the same number of inspections (approximately 212,000), demonstrating greater productivity and operational effectiveness. • This resulted in a significant improvement in our accuracy rate, increasing from 12% in 2024 to 25% in 2025, more than doubling our fraud detection accuracy rate. In addition to identifying more irregularities, we increased our efficiency in revenue recovery, reaching R$75 million in 2025, approximately five times the amount recovered in 2024, reinforcing the economic impact of our anti-fraud actions. Our digital transformation is underway, with several initiatives in progress, including the Electronic TOI (Irregularity Report) and the robotic automation of irregularity calculations through the implementation of RPA (Robotic Process Automation), resulting in approximately 9,000 calculations completed and R$19.5 million recovered within two months of implementation. In 2025, we commenced the modernization of our metering infrastructure, a program that will deploy approximately 4.4 million ultrasonic meters with NB-IoT telecommunications and embedded shut-off valves by 2029. We believe this will make our AMI project the largest Smart Water Metering initiative in the world, promoting operational efficiency, reducing losses and unpaid debts, and empowering our customers to actively manage their water consumption. This solution was developed based on extensive international benchmarking and reflects global best practices in smart water metering. Additionally, we replaced approximately 1.5 million obsolete meters in customer. In aggregate, we estimate that these metering initiatives will generate a net present value (NPV) of over R$8 billion, with an internal rate of return (IRR) ranging between 39% and 52%. Customer Relationship In 2025, customer relationship management maintained its position as a central pillar of our strategy, supporting organizational, digital, and process transformation. The initiatives developed throughout the year focused on making service more agile, expanding access to services, and ensuring increasingly positive interactions with customers, in compliance with the regulations applicable to the basic sanitation sector in the State of São Paulo. Our customer relationship strategy is structured around an integrated approach combining technological modernization, service process redesign, and evolution of management models. Throughout 2025, we worked to reduce barriers in the customer journey, increase the transparency of interactions, and offer faster and more predictable responses, with the goal of strengthening trust and the efficiency of the services provided. 48 Table of Contents We advanced in the digitalization of our relationship channels through the integration of platforms and the expansion of our omnichannel model. Digital channels now play a significant role in transactional service and customer communications, enabling access to information, service requests, demand tracking, and digital payment processing, including via PIX (Brazil’s instant payment system) and credit cards. This process included the modernization of our customer relationship management (CRM) systems through the gradual implementation of the Salesforce platform, as well as the redesign of critical customer journeys and the expansion of functionalities available on digital channels, contributing to the standardization of service and the simplification of processes. We have also expanded the use of automated channels and artificial intelligence-based solutions, including IBM Watson-powered Interactive Voice Response (IVR) systems in our telephone service operations, with the aim of increasing service capacity, reducing average response time, and redirecting human resources to more complex demands. These solutions support the resolution of recurring requests and guide customers throughout the service process, contributing to the efficiency of our channels and reducing demand for in-person and telephone support. Our omnichannel strategy was complemented by the continuous evolution of our mobile application and virtual agency, which consolidated functionalities previously distributed across different channels. In face-to-face and field service, we adopted technological solutions aimed at expanding payment options, with the goal of facilitating debt settlement and reducing operational barriers in customers’ financial interactions with us. In 2025, our customer satisfaction survey, conducted by GRM Pesquisa de Mercado, indicated a satisfaction rate of 82%, compared to 83% for the year ended December 31, 2024. Our net promoter score, which measures customer loyalty and likelihood to recommend our services, was 47 for 2025, compared to 44 for 2024. The results of these indicators are used as inputs for the continuous improvement of our customer relationship policies and processes. The strengthening of customer relationships is linked to our pursuit of operational efficiency and long-term financial sustainability. The integration of technology, processes, and business areas contributes to improved productivity and collection processes, while supporting our long-term objectives related to the adequate, continuous, and universal provision of services. Contract URAE-1 Tariffs Tariffs are our main form of remuneration for the services we provide under the Concession Agreement for URAE-1. Under the Concession Agreement for URAE-1, the tariffs aim to remunerate the investment effectively made and incorporated into the concession’s asset base. There are two tariffs: the application tariff, which is what the user actually pays, and the equilibrium tariff, which is owed to us. Any difference between the application tariff and the equilibrium tariff is covered by FAUSP. Tariff adjustments for our services follow the guidelines established by regulatory standards including the Concession Agreement for URAE-1 and its schedules, especially Schedule V. These guidelines establish procedural steps and the terms for the annual adjustments, which are to be conducted by ARSESP. The approved regulatory model adopted by ARSESP for the Concession Agreement for URAE-1 defines a maximum average tariff (P0), based on the guarantee of the economic and financial balance of the provider, such as us, in its business segment and on efficient costs projected for the tariff cycle, to encourage the provider to permanently seek to reduce its costs. Accordingly, an average tariff is established, expressed in reais per cubic meter, which reflects the economic cost of providing water and sewage services in a tariff cycle of five years. The methodology is based on a backward-looking approach, in which the equilibrium tariff is calculated by building blocks, considering costs, investments and the reference market ex-post to their realization, as observed in the reference period. 49 Table of Contents Within the scope of periodic tariff reviews, the calculation parameters for the tariff components — such as the rate of return (WACC), the X-Factor, and efficient operating costs — will be defined by ARSESP, in accordance with the criteria and methodologies set forth in Annex V – Regulatory Model, which structures all tariff-setting processes. Further to the reviews, the tariffs under the Concession Agreement for URAE-1 are adjusted annually. The tariff adjustment procedure follows the provisions set forth in Annex V and incorporates inflation variation (IPCA price index accumulated over the past 12 months), any deductions resulting from non-compliance with universalization targets (U-Factor) and quality indicators (Q-Factor), as well as the application of an efficiency-sharing factor starting from the 3rd Tariff Cycle (the X-Factor). In addition to inflation and performance mechanisms (U-Factor and Q-Factor), during the first two tariff cycles (2024–2034), annual adjustments will also take into account the reassessment of the equilibrium tariff revenue. This reassessment is intended to update the regulatory asset base and the reference market, in accordance with the formula specified in Annex V of the Concession Agreement for URAE-1. The adjustments cover a 12-month period, except for the first one, which covered the period between the effective date of the Concession Agreement for URAE-1 (July 23, 2024) and December 31, 2025. For all adjustments, December will be used as the base month for regulatory approval, and January 1 of the following year will be the effective date for the application of the updated tariffs, subject to the availability and publication of the official inflation indices. Throughout 2025, the tariffs remained unchanged because the Concession Agreement for URAE-1 established that the tariff schedule set forth in Annex IV would remain fixed until December 2025. As a result, the tariff levels applied from the effectiveness of the Concession Agreement for URAE-1 in July 2024 continued unchanged for the entire 2025 calendar year. For more information, see “Item 3.D. Risk Factors — We are exposed to risks associated with the Concession Agreement for URAE-1, which may materially impact our financial condition and operating results” and “Item 10.F Additional Information – C. Material Contracts — Concession Agreement for URAE-1.” Tariff Structure Our current tariff structure, governed by State Decree No. 41,446/1996 and by the Concession Agreement for URAE-1, is divided into residential and non-residential categories. The residential category is subdivided into standard residential, residential-social, and vulnerable residential tariffs. Social tariffs benefit low-income families, the unemployed, and collective living residences, while vulnerable tariffs support urban areas lacking urban infrastructure. In addition, the tariff structure includes an unmetered rural category, applicable to connections used exclusively in rural units whose service delivery systems differ from those of other categories; the tariff for this category is equal to the fixed charge applied to the standard residential category. The non-residential category consists of: (i) commercial, industrial and public customers; (ii) nonprofit entities that pay 50.0% of the prevailing non-residential tariff; (iii) government entities that adhere to the Rational Use of Water Program (Programa de Uso Racional da Água – “PURA”) and pay 75.0% of the prevailing non-residential tariff; and (iv) public entities that have entered into program agreements, for municipalities with a population of up to 30.0 thousand and with half or more classified according to their degree of social vulnerability by the Social Vulnerability Index of São Paulo (Índice Paulista de Vulnerabilidade Social) 5 and 6, of the SEADE, obtained through the analysis of the 2000 Census figures, which start to receive tariff benefits, in accordance with our normative ruling, for the category of public use, at the municipality level. The tariffs for entities described in item (iv) are equal to those offered to the nonprofit entities mentioned in item (ii) above, corresponding to 50.0% of the public tariffs without contractual provisions referred to in item (iv) above. Social Tariff Update On August 1, 2025, ARSESP Resolution No. 1,699 established the criteria and procedures for classifying users within the Social Residential and Vulnerable Residential tariff categories and introduced the “Tarifa Social Paulista” program. Subsequently, on August 7, 2025, the Second Amendment to Concession Agreement No. 01/2024 was executed, further updating the definitions and tariff structure related to the social tariff program. 50 Table of Contents ARSESP Resolution No. 1,699/2025 and the Second Amendment to Concession Agreement No. 01/2024 did not change the eligibility criteria for the Vulnerable Residential category. However, for the Social Residential category, the resolution and the Second Amendment to Concession Agreement No. 01/2024 expanded eligibility by adding a new criterion for households registered in CadÚnico with per-capita income of up to half the minimum wage that include a person with disabilities or an elderly individual aged 65 or older receiving the federal continuous cash benefit program (Benefício de Prestação Continuada — “BPC”). In addition to the existing Social Tariff and Vulnerable Tariff, which benefit users enrolled in the Federal Government’s Single Registry (Cadastro Único), the program introduced the Social Tariff II category to expand eligibility to users who meet the following criteria: they reside in informal urban settlements (favelas); are included in a regularization program carried out by us; reside in areas characterized by social vulnerability, including informal settlements and low-income urban communities; or live in areas inhabited by indigenous peoples, traditional communities, or rural populations. There are tariff tables with the values due for each consumption pricing range for these categories: up to 10 m³, from 11 to 20 m³, from 21 to 50 m³, and above 50 m³. The “Residential Social” and “Residential Vulnerable” categories have five consumption pricing ranges: up to 10 m³, from 11 to 20 m³, from 21 to 30 m³, from 31 to 50 m³, and above 50 m³. The amount charged is always progressive. Large consumers and municipalities served by wholesale have separate tariff tables. Water and Sewage Services Tariffs Under the current tariff structure, we establish separate tariff schedules for our services in each of the São Paulo metropolitan regions and each of the interior regions of the State of São Paulo and the coastal regions, depending on whether a customer is located in the São Paulo metropolitan region or the interior of the State of São Paulo and in the coastal regions of São Paulo. Each tariff schedule incorporates regional cross-subsidies, taking into account the customer type and volume of consumption. Where tariffs paid by customers with high monthly water consumption rates exceed our costs of providing water services, we use the excess tariff billed to high-volume customers to compensate for the lower tariffs paid by low-volume customers. Similarly, tariffs for non-residential customers are set at levels that subsidize residential customers. In addition, the tariffs for the São Paulo metropolitan region generally are higher than tariffs in the interior region of the State of São Paulo and the coastal regions. In the years ended December 31, 2025 and 2024, the average tariff calculated for the interior of the State of São Paulo and in the coastal regions of São Paulo was approximately 20% below the average tariff of the São Paulo metropolitan region. 51 Table of Contents The following table sets forth the water tariffs by (i) customer category and class; and (ii) volume of water consumed, charged in cubic meters during the years and period stated in the São Paulo metropolitan region: As from July 23, As from July 23, As from May 10, As from May 10, As from May 10, 2025 2024 2024 2023 2022 (in reais) Standard Residential: 0-10(1) 3.80 3.80 3.83 3.59 3.27 11-20 6.01 6.01 6.01 5.62 5.13 21-50 14.98 14.98 14.98 14.00 12.78 Above 50 16.50 16.50 16.50 15.43 14.08 Social: 0-10(1) 1.08 1.08 1.20 1.12 1.02 11-20 2.05 2.05 2.05 1.92 1.75 21-30 7.32 7.32 7.32 6.84 6.24 31-50 10.42 10.42 10.42 9.74 8.89 Above 50 11.51 11.51 11.51 10.77 9.83 Urban areas occupied by low-income populations in irregular areas (favelas): vulnerable social starting in 2021: 0-10(1) 0.82 0.82 0.91 0.85 0.78 11-20 1.03 1.03 1.03 0.96 0.88 21-30 3.45 3.45 3.45 3.23 2.95 31-50 10.42 10.42 10.42 9.74 8.89 Above 50 11.51 11.51 11.51 10.77 9.83 Social II: 0-10(1) 1.90 - - - - 11-15 3.01 - - - - 16-20 6.01 - - - - 21-50 14.98 - - - - Above 50 16.50 - - - - Commercial/Industrial/Governmental: 0-10(1) 7.66 7.66 7.70 7.20 6.57 11-20 14.98 14.98 14.98 14.00 12.78 21-50 28.71 28.71 28.71 26.84 24.50 Above 50 29.90 29.90 29.90 27.96 25.52 Social Welfare Entities: 0-10(1) 3.83 3.83 3.85 3.60 3.28 11-20 7.48 7.48 7.48 6.99 6.38 21-50 14.41 14.41 14.41 13.47 12.29 Above 50 14.97 14.97 14.97 13.99 12.77 Public Entities with contract: 0-10(1) 5.74 5.74 5.77 5.39 4.92 11-20 11.22 11.22 11.22 10.48 9.57 21-50 21.59 21.59 21.59 20.18 18.42 Above 50 22.44 22.44 22.44 20.98 19.15 (1) The minimum volume charged is ten cubic meters per month. Sewage charges in each region are fixed and based on the same volume of water charged. In the São Paulo metropolitan region and the coastal region, the sewage tariffs are equal to the water tariffs. In the majority of the municipalities of the interior region of the State of São Paulo, sewage tariffs are approximately 20.0% lower than water tariffs. Wholesale water rates are the same for all municipalities served in the São Paulo metropolitan region. We provide sewage treatment services to those municipalities in line with the applicable contracts and tariffs. In addition, various industrial customers pay an additional sewage charge, depending on the characteristics of the sewage they produce. Each category and class of customer pays tariffs according to the volume of water consumed. The tariff paid by a certain category and class of customer increases progressively according to the increase in the volume of water consumed. The first tranche (0–10 m³) corresponds to the minimum fee charged to our customers for the consumption of water. 52 Table of Contents Contract SABESP Olímpia S/A Tariffs Public Tender No. 02/2023 awarded SABESP Olímpia a 30-year concession to operate water supply and wastewater services in the Municipality of Olímpia. The concession contract was signed on October 11, 2023, and operations began on December 10, 2023. The tariff defined in the tender process is intended to ensure the economic and financial equilibrium of the concession by covering efficient operating costs, contractual obligations, and required investments. Brazilian legislation guarantees the right to maintain such equilibrium, and the concession contract confirms that it must be preserved whenever contractual conditions are met. The economic and financial equilibrium is determined through a discounted cash flow model that reflects the tariff revenue needed to achieve the internal rate of return accepted in the winning bid, set at 11.88%. The concession provides for both ordinary tariff reviews, conducted every five years, and extraordinary reviews, which may be triggered by events that alter the contractual risk allocation or financial conditions. In addition to these review mechanisms, the tariff and the public prices of complementary services are subject to an annual adjustment, applied every 12 months, based on the accumulated variation of the IPCA. Regulatory Adjustments. ARES-PCJ approved a 9.52% tariff adjustment effective November 17, 2024, covering water and sewage tariffs as well as the public prices for other services, as set forth in Resolution No. 583. On October 21, 2025, ARES-PCJ approved an additional 5.17% adjustment under Resolution No. 659, corresponding to the accumulated IPCA for the period from October 2024 through September 2025. In the same proceeding, ARES-PCJ also approved a 3.27% tariff review to restore the contractual economic and financial equilibrium in light of specific imbalance events, including the implementation of the Residential Social Tariff under Federal Law No. 14,898/2024, set at 8.61%. These adjustments were compounded with the general adjustment and applied on December 4, 2025. Tariff Structure Under the Olímpia Concession Agreement, the tariff structure is organized into residential and non-residential categories, with separate schedules for water and sewage services. The residential category may include sub-categories aligned with social policy instruments defined by the applicable regulatory framework. The non-residential category comprises commercial, industrial, public, and mixed customers. For all categories, charges are assessed by progressive consumption blocks, and the first tranche (0–10 m³) corresponds to the minimum charge, which is billed regardless of actual water or sewage consumption. Large-volume users and specific service modalities may be subject to dedicated tariff tables, as provided for in the concession and the regulator’s rules. Social Tariff Update. Following Federal Law No. 14,898/2024, the criteria and discounts applicable to the Residential Social Tariff in Olímpia were revised to align with the new legal framework. ARES-PCJ updated its rules accordingly, and the revised tariffs and eligibility criteria became effective in early 2025. There are tariff tables with the values due for each consumption pricing range for these categories: up to 10 m³, from 11 to 20 m³, from 21 to 30 m³, from 31 to 50 m³, from 51 to 60 m³, from 61 to 70 m³, and above 70 m³. The "Residential Social" category has eight consumption pricing ranges: up to 10 m³, from 11 to 15 m³, from 16 to 20 m³, from 21 to 30 m³, from 31 to 50 m³, from 51 to 60 m³, from 61 to 70 m³, and above 70 m³. The following table sets forth the water tariffs by customer category, class, and consumption range, expressed in cubic meters, applicable to the Olímpia concession during the periods shown: 53 Table of Contents Customer Category Consumption As from December 4, 2025 As from November 17, 2024 Standard Residential: 0-10(1) 2.53 2.33 11-20 5.09 4.69 21-30 5.16 4.75 31-50 6.40 5.89 51-60 9.24 8.51 61-70 9.37 8.63 Above 70 9.42 8.67 Social: 0-10(1) 1.27 - 11-15 2.55 - 16-20 3.82 - 21-30 5.16 - 31-50 6.40 - 51-60 9.24 - 61-70 9.37 - Above 70 9.42 - Commercial 0-10(1) 3.62 3.33 11-20 6.36 5.86 21-30 6.39 5.88 31-50 7.99 7.36 51-60 9.28 8.54 61-70 9.37 8.63 Above 70 9.42 8.67 Public: 0-10(1) 7.82 7.20 11-20 7.62 7.02 21-30 7.70 7.09 31-50 10.40 9.58 51-60 11.82 10.88 61-70 11.93 10.98 Above 70 12.03 11.08 Industrial: 0-10(1) 7.24 6.67 11-20 7.07 6.51 21-30 7.10 6.54 31-50 9.59 8.83 51-60 10.82 9.96 61-70 10.87 10.01 Above 70 11.01 10.14 Mixed 0-10(1) 3.08 2.83 11-20 5.73 5.28 21-30 5.78 5.32 31-50 7.20 6.63 51-60 9.28 8.54 61-70 9.37 8.63 Above 70 9.42 8.67 (1) The minimum volume charged is ten cubic meters per month. The sewage tariff is equal to 80% of the applicable water tariff. The first tranche (0–10 m³) reflects the minimum charge, assessed independently of the customer’s actual water or sewage consumption. Government Regulations Applicable to our Contracts Basic sanitation services in Brazil are subject to extensive federal, state and local legislation and regulations. From a federal regulatory perspective, the current legal framework for basic sanitation (Federal Law No. 14,026/2020) granted the National Water and Basic Sanitation Agency (ANA) the authority to issue reference standards for how subnational regulatory agencies should regulate the sector. These reference standards cover, among other topics: (i) quality and efficiency standards for the services provided, including the maintenance and operation of basic sanitation systems; (ii) tariff regulation; (iii) standardization of contractual instruments for basic sanitation concessions; (iv) targets for the universalization of services; (v) criteria for regulatory accounting; (vi) progressive reduction and control of water losses; (vii) methodologies for calculating indemnities for investments not yet amortized or depreciated; (viii) governance standards for regulatory entities; (ix) rules regarding the reuse of treated effluents; (x) parameters for determining the termination of service provision; (xi) standards relating to the transition from unitary sewage systems to separate systems; (xii) systems to assess targets for the expansion and universalization of service coverage; and (xiii) minimum standards for full service provision and economic and financial sustainability. 54 Table of Contents Key reference standards issued by ANA to date include: (i) Reference Standards Nos. 03/2023 and 01/2024, which set the methodology for indemnifying unamortized or depreciated investments; (ii) Reference Standard No. 05/2024, which introduces a risk matrix for public water supply and sanitation contracts; (iii) Reference Standards Nos. 06/2024 and 13/2025, which regulate tariff models for water supply and sewage services; (iv) Reference Standard No. 09/2024, which sets operational indicators; (v) Reference Standard No. 11/2024, which standardizes water supply and sewage services across subnational regulatory entities; (vi) Reference Standard No. 13/2025, which establishes the tariff structure and social tariff for water supply and sewage services; and (vii) Reference Standard No. 15/2025, which sets forth guidelines for the progressive reduction of losses in water supply systems. Although ANA’s reference standards are not legally binding on subnational regulatory agencies, compliance is incentivized by their being a condition for access to federal financing and public funds. As a result, any delay in the issuance, adoption, or interpretation of such standards, or inconsistencies in their implementation by subnational regulators, may adversely affect the regulatory environment applicable to our operations. From a state regulatory perspective, the São Paulo State Public Services Regulatory Agency (ARSESP) is the authority responsible for regulating and overseeing public water supply and sewage services related to the Concession Agreement for URAE-1. ARSESP’s responsibilities include: (i) setting and adjusting applicable tariffs; (ii) establishing technical standards, recommendations, and procedures for service provision; (iii) defining criteria, indicators, formulas, quality standards, and performance parameters; and (iv) monitoring service performance and applying sanctions. ARSESP charges a regulatory oversight fee of 0.50% of the revenues directly derived from the services it regulates, net of applicable taxes. ARSESP Resolution No. 1,635/2025 established the regulatory agenda for 2025 and 2026, which includes: (i) updating the methodology for certification and validation of regulatory assets; (ii) updating the methodology for annual certification of investments in the sanitation sector; (iii) updating the definitions for charging customers with public network availability of water and sewage services who are not connected to the system; (iv) updating the quality indicator for pavement replacements in accordance with applicable municipal laws; (v) proposing alternative solutions adapted to local conditions, including informal and rural areas; and (vi) updating and standardizing the methodology for sharing efficiency gains (Factor X) for regulated gas pipeline and basic sanitation companies. Changes in ARSESP’s regulatory approach may affect certain aspects of our operations or require adjustments to our processes or investments. Although these regulatory activities are part of the ordinary course of the sector and we maintain ongoing engagement with the regulator, certain decisions may influence our operating costs, timelines, or expected returns under our concession agreements. From a local regulatory perspective, municipalities are responsible for addressing matters of local interest, such as zoning within their territories and any conditions that may apply to our operations. In municipalities where services are provided outside a regionalized framework — such as in Olímpia — the municipality is responsible for delegating regulatory and oversight authority to a designated entity or exercising such powers directly through its own administrative body. Under the Concession Agreement for URAE-1, we are entitled to seek the restoration of the economic and financial equilibrium of the concession for impacts arising from the creation, repeal, or revision of rules issued by ANA, the granting authority, ARSESP, the State, or the municipalities, to the extent such rules affect our concession activities. The restoration of such equilibrium must preferably be addressed through periodic tariff reviews; however, regulatory changes that materially affect our solvency or liquidity may be addressed through extraordinary tariff reviews. For more information, see “Item 3.D. Risk Factors—We are exposed to risks associated with the Concession Agreement for URAE-1, which may materially impact our financial condition and operating results.” 55 Table of Contents Agreements with Municipalities and Metropolitan Regions In metropolitan regions, conurbations and microregions, the authority for public water and sewage systems is shared between states and municipalities. For other municipalities, the primary responsibility rests with the municipality itself. ARSESP ARSESP regulates, controls and supervises piped gas and basic sanitation services in São Paulo. It oversees state-owned services and those delegated to the state, including tariff regulation, while respecting municipal competencies. ARSESP charges a fee of 0.50% of the revenue directly obtained with the service provision it regulates, less taxes levied on it. ARSESP has addressed the methodology and criteria for updating the Regulatory Remuneration Base (Base de Remuneração Regulatória), along with the procedures for the Annual Certification of Investments for companies in the basic sanitation sector. Topics covered include asset control for basic sanitation concessionaires, general conditions for the provision and use of public urban cleaning and solid waste management services, and the risk allocation matrix associated with the provision of water supply and sewage services. Following our Privatization, ARSESP Resolution No. 1635/2025 established the regulatory agenda for 2025 and 2026, which includes: • Updating the methodology for certification and validation of regulatory assets; • Updating the methodology for annual certification of investments in the Sanitation sector; • Updating the definitions for charging clients with public network availability of water and sewage services who are not connected to the system; • Updating the quality indicator of pavement replacements according to municipal laws; • Proposing alternative solutions adapted to the local reality, individual or collective, including informal and rural areas; and • Updating and standardizing the methodology of the sharing of efficiency gains (Factor X) for regulated gas pipeline and basic sanitation companies. Marketing Channels As of December 31, 2025, we were the concessionaire responsible for providing water supply and sewage collection, treatment, and disposal services directly to end consumers in 375 municipalities in the State of São Paulo. For more information on our marketing channels targeted at individual customers, see “Item 4.B Business Overview—Customer Relationship.” We also supplied water and sewage services on a wholesale basis to two municipalities in the São Paulo metropolitan region. These municipalities are responsible for distributing the water to end consumers. Due to the structure of our distribution network, end consumers in areas served on a wholesale basis cannot obtain water services directly from us. For more information regarding our service concessions, see “Item 4.B Business Overview—Water Operations.” For more information on our marketing channels aimed at municipalities, see “Item 4.B Business Overview—Competition — Competition for New Municipalities.” Power Consumption Power is essential to our operations and, as a result, we are one of the largest users of energy in the State of São Paulo. In the year ended December 31, 2025, we used 3.259 GWh. Any significant disruption of energy supply could have a material adverse effect on our business, financial condition, results of operations, or prospects. Energy prices have a significant impact on our results of operations. For the year ended December 31, 2025, we purchased approximately 76.0% of our total energy consumption in the independent energy contracting market (Ambiente de Contratação Livre or Mercado Livre de Energia, or “ACL”) where we can more efficiently negotiate the supply of energy because we can take advantage of market opportunities; and the remainder of our energy consumption comes from the regulated energy contracting market (Ambiente de Contratação Regulado or Mercado Cativo, or “ACR”), where energy is priced through tariffs set by the National Electric Energy Agency (Agência Nacional de Energia Elétrica, or “ANEEL”). 56 Table of Contents In 2019, we began structuring a distributed power generation program (Programa de Geração Distribuída - Energia Fotovoltaica) focused on solar energy. The program estimates that until the end of 2027, we will have a power generation capacity of around 60 MW, with a daily average output of 28 MWh, corresponding to about 4% of our total energy consumption (based on energy consumed during 2025). By 2025, we had installed 36 photovoltaic power generation plants, with a power generation capacity of 50 MW. The credits obtained as part of this distributed generation were used to offset energy consumption of low voltage installations, which have a higher tariff. As such, about 55% of our low-voltage energy consumption is supplied by renewable energy. The total investment contemplated by this program is approximately R$320.0 million, with an estimated payback period of seven to eight years. Insurance We maintain insurance covering, among other things, fire or other damage to our property and office buildings and third-party liabilities. We also maintain insurance coverage for directors’ and officers’ liability (“D&O Insurance”). We currently obtain our insurance policies via Requests for Proposals (“RFPs”) involving major global insurance companies that operate in Brazil. For the year ended December 31, 2025, we paid R$162.2 million in premiums, of which R$9.4 million related to our D&O Insurance policy. Our insurance policies covered R$126.6 billion in assets and third-party liabilities, including coverage of R$210.0 million under our D&O Insurance policy, as well as Engineering Risk Insurance, Operational Risk Insurance, Environmental Risk Insurance, and General Liability Insurance. We do not have insurance coverage for business interruption risk because we believe that the low risk of significant interruption to our activities does not justify the high premiums for such insurance. We believe that we maintain customary insurance levels for our type of business in Brazil. For further information, see “Item 3.D. Risk Factors — Risks Relating to the Regulatory Environment — Risks associated with the collection, treatment and disposal of wastewater and the operation of water utilities may impose significant costs that may not be covered by insurance, which could result in increased insurance premiums.” Intellectual Property Trademarks and copyrights We have secured registration of our trademark (“Sabesp”) in its nominative form in Class 37 (i.e., energy, water, gas and sewage distribution and control services) at the Brazilian Institute of Industrial Property (Instituto Nacional da Propriedade Industrial - “INPI”). In addition, we have registered other trademarks with the INPI. We have also registered figurative trademarks for twelve characters and have secured copyright registration for the character “Sani” with the School of Fine Arts of the Federal University of Rio de Janeiro (Escola de Belas Artes da Universidade Federal do Rio de Janeiro - UFRJ). Of the trademark applications we have filed with the INPI, only one remains pending final decision and registration. Patents We have seven patents granted by the INPI: (i) a device for the removal of supernatants during the sewage treatment process, (ii) a rotary device used to clean water reservoirs transported by trucks with high-pressure hydro-jetting systems, (iii) a bubble removal system, autonomous micro-laboratory, and use of an autonomous micro-laboratory to monitor water quality, together with USP, (iv) a chemical composition sensor, its fabrication process and its use to measure pH in microfluid systems, together with USP, (v) water leakage detection equipment: method and simulation bench for leakage in lines, together with FAPESP and UNESP, (vi) a device for the installation of water meters; and (vii) a modular system for the treatment of sanitary sludge and the process using this system. 57 Table of Contents We have filed patent applications for additional devices and inventions, some of which have been jointly filed with certain Brazilian universities pursuant to our cooperation agreements with these institutions. We currently have nine patent applications pending before the INPI. In addition to these Brazilian patent applications, we also filed two international patent applications under the Patent Cooperation Treaty (“PCT”), designating the European Patent Office. In 2025, we obtained a European patent entitled “Method and System for Analyzing and Providing a Quality Index for a Noise Correlator” for water leakage detection equipment, filed jointly with FAPESP and UNESP. We currently have one patent application pending under the PCT system. For more information on our cooperation agreements with Brazilian universities and FAPESP, see “Item 5. Operating and Financial Review and Prospects —C. Research and Development, Patents and Licenses, etc. —Research and innovation.” Software We have adopted an internal policy that provides for an active and effective audit and prevention of unauthorized software use. We have acquired temporary the software licenses for the use of third-party software, through contracts and/or other legally valid instruments, which are required for all of our workstations. We have also developed 28 computer programs for management and control of water and sewage treatment facilities, as well as for third-party services management for the management and control of the water treatment process and Electric energy management system. We have also registered the proprietary computer programs at the INPI. Domain Names We own the domain names listed below, which have been registered with the relevant entity in Brazil, Registro.br: • www.sabesp.com.br; • www.revistadae.com.br; • Sabesp2via.net; and • www.clubinhosabesp.com.br. Environmental Matters Given the multidisciplinary nature of sanitation services, in addition to developing a corporate climate strategy, we undertake several initiatives aimed at preserving the environment. Our current corporate strategy places sustainability at the core of our business, and our environmental initiatives have gained momentum, reflecting our commitment to proactively addressing the most pressing environmental and climate challenges. Environmental management is integral to the provision of our services and to our core business strategy. Our performance is guided by established environmental standards and monitored through an integrated approach to ensure the sustainability of our operations. With the recent organizational restructuring, the environmental licensing process for works and projects, which was previously decentralized among our various business areas, has been centralized in a single department, enabling a comprehensive overview covering all phases of the process, from conception to decommissioning of facilities. The management of compliance with the conditions of our environmental licenses has also been incorporated into this centralized function. 58 Table of Contents This centralized management brings several benefits. By concentrating on the licensing process within a single area, we have enhanced the efficiency of our management, standardized and simplified procedures, and optimized internal communication. This also provides a more comprehensive and integrated perspective on our activities, enabling a more strategic and consistent approach to environmental issues. By incorporating the management of compliance with environmental license conditions into this function, we further reinforce our commitment to legal compliance and sustainability. We have the following ongoing environmental programs, managed by our Environmental, Regulatory and Sustainability corporate areas: • Management of GHG emissions, including: conducting annual GHG inventories; promoting awareness-raising activities on climate issues; encouraging and supporting the reduction of GHG emissions in our operations; conducting studies to identify the potential for carbon sequestration and storage in our forest reserves; performing climate change risk and resilience assessments; and adhering to relevant national and international initiatives and guidelines. In 2023, 2024 and 2025, we were awarded the GHG Inventory Gold Seal by the Brazilian GHG Protocol Program. For more information, see “Item 4.B. Business Overview — Environmental Matters — Climate Change Regulations: Reduction of Greenhouse Gases (GHG) Emissions;” • Corporate program for obtaining and maintaining licenses for water treatment plants, sewage treatment plants, and sewage pumping stations (Programa Corporativo de Obtenção e Manutenção de Licenças de Estações de Tratamento de Água, Estações de Tratamento de Esgotos e Estações Elevatórias de Esgotos), designed to meet the requirements of the licensing authority and to establish procedures for the renewal and ongoing maintenance of these licenses. We have had a program since 2017, approved by CETESB, relating to the operational licenses of sewage pumping stations. In 2022, a similar program was approved by CETESB for water treatment plants and wastewater treatment plants; • Corporate program for obtaining and maintaining grants for the use of water resources (Programa Corporativo de Obtenção e Manutenção das Outorgas de Uso de Recursos Hídricos), including water collection, effluent discharge and dams operations. The grant provides the necessary resources to subsidize the processing of use of and payment for water resources. We are the biggest payer for water use in the State of São Paulo; • Environmental education program (Programa de Educação Ambiental - “PEA”), an important tool for strengthening the effectiveness of our sanitation activities, which propitiates connections with the communities we service through over several environmental education projects. The activities developed by the PEA are organized with the following objectives: raise awareness of the intrinsic value of water; protect the environment; preserve water bodies; improve the quality of the environment; raise awareness of sanitation activities; and raise awareness of the conscious use of water; • Management of our institutional representation in the state and national systems of water resources, including training of company representatives to participate in: (i) the creation of criteria for water usage charges, (ii) preparation and review of river basin plans (Planos de Bacias), (iii) review of water bodies’ classifications, and (iv) analysis of legislations regarding the protection of water sources; • SABESP 3Rs program (Programa SABESP 3Rs) for the reduction, reuse and recycling of waste from administrative activities, in partnership with waste and recycling collecting cooperatives and which includes employee training enabling them to act as multipliers in the roll-out of the program; • Progressive implementation and maintenance of the Environmental Management System (“EMS”) in our water and sewage treatment plants aiming to improve the efficiency of the systems, manage the risks and implement preventive actions to avoid impacts on the environment, considering the relevance of these plants for our core activity. Since 2015, we have been working on the EMS with a mixed model, whereby the ISO 14001 standard is applied to a limited number of certified plants, while the other plants adopt the environmental management model developed internally (named SGA-SABESP), without aiming certification. The EMS is currently in place in 834 treatment plants, 35 of which are ISO 14001 certified, representing 100% of our treatment plants. 59 Table of Contents • Corporate program of environmental recovery commitment terms (Programa Corporativo de Termos de Compromisso de Recuperação Ambiental) arising from the environmental licensing of new ventures, which includes obligations of forest restoration with environmental compensation purposes, when necessary. From 2017 to 2025, we accounted for 2,758 thousand buds for plantation. Of these, 1,536 thousand have already been planted. To provide technical support for environmental programs, we carry out corporate training on topics related to environmental management. This initiative aims to promote continuous professional development with specific content aimed at strategic, management and operational teams. In addition to corporate environmental management actions, we have several projects and initiatives underway to benefit the environment, such as actions to protect water springs, projects for the rational use of water, reuse of effluents, projects for the use of photovoltaic energy and biogas as vehicle fuels, as well as other environmental projects focused on the engagement of the population at large. We are a signatory of the United Nations Global Compact, support the 17 United Nations Sustainable Development Goals and maintain a partnership with the United Nations Framework Convention on Climate Change (UNFCCC). These initiatives aim to stimulate actions in areas of crucial importance to humanity, the planet, countries and companies, including the enhancement of sanitation services for the preservation of the environment, quality of life and the mitigation of climate change. Climate Change Regulations: Reduction of Greenhouse Gases (GHG) Emissions We are required to comply with laws and regulations related to climate change, including international agreements and treaties to which Brazil is signatory. At the state level, we are also subject to the State Policy on Climate Change for the State of São Paulo (Law No. 13,798/2009), regulated by Decree No. 68,308/2024. At the federal level, we are subject to the National Climate Change Policy (Law No. 12,187/2009), regulated by Decree No. 9,578/2018. Also at the federal level, in 2024 the Brazilian Greenhouse Gas Emissions Trading System (SBCE) was created by Law No. 15,042/24, which has not yet been regulated. In 2025, we concluded our annual GHG inventory, revealing that sewage collection and treatment activities are our main source of GHG emissions, accounting for 76.7% of our total annual GHG emissions in the year ended December 31, 2025. Electricity accounted for 6.04% of our total annual GHG emissions in the year ended December 31, 2025. As we expand our services, we expect increased organic loads and GHG emissions but also contribute to reducing GHG emissions in aquatic ecosystems, aligning with the Climate Action Plan 2050. We are exploring less carbon-intensive alternatives in our operational activities and with the support of a specialized consultancy, both in the context of adaptation and climate mitigation. We have already evaluated plans for a series of actions aimed at reducing GHG emissions, including: • the use of complementary technologies and the optimization of the operations in sewage treatment plants; • the expansion of the beneficial use of biogas and generated sludge; • the expansion of the use of clean and renewable energy sources and alternative fuels; and • activities of forest conservation and restoration. Among the actions already implemented or currently in progress, we highlight the following examples, as detailed in the paragraphs below. Additionally, we are developing projects aimed at generating clean, renewable, and sustainable energy. In 2019, we began structuring a distributed power generation program (Programa de Geração Distribuída - Energia Fotovoltaica) focused on solar energy. The program estimates that until the end of 2027, we will have a power generation capacity of around 60 MW, with a daily average output of 28 MWh, corresponding to about 4% of our total energy consumption (based on energy consumed during 2025). By 2025, we had installed 36 photovoltaic power generation plants, with a power generation capacity of 50 MW. The energy credits obtained as part of this distributed generation were used to offset energy consumption of low voltage installations, which have a higher tariff. As such, about 55% of our low-voltage energy consumption is supplied by renewable energy. The total investment contemplated by this program is approximately R$320.0 million, with an estimated payback period of seven to eight years. 60 Table of Contents We produce agricultural compost, “Sabesfértil”, from sludge at a wastewater treatment plant in the municipality of Botucatu. Similar projects for the use of sludge from wastewater treatment plants are under development at our other plants. In the coastal region, we have developed a system for the solar drying of wastewater treatment plant sludge with forced ventilation and mechanized mixing and fragmentation of the sludge. A similar project is already in operation in a wastewater treatment plant located in the central-west region of the state. In the Franca wastewater treatment plant, we use biogas to produce vehicle fuel to supply part of our fleet, reducing GHG emissions. We also have projects to cover sewage treatment anaerobic lagoons to capture and burn the biogas. We are developing methane reduction projects and energy recovery initiatives at wastewater treatment plants, along with research into small hydro-generators. We have also implemented projects for the covering of anaerobic lagoons with the covering supported in the liquid surface. We are implementing sustainability initiatives in our corporate vehicle fleet. This significantly reduced annual gasoline consumption, avoiding GHG emissions. We engage in discretionary forest reserve maintenance and restoration activities, contributing carbon sequestration and climate adaptation. We preserve more than 36,000 hectares of rain forest (Mata Atlântica) within legally protected areas (Brazilian conservation units), where the main metropolitan springs and water reservoirs are located. Water Usage The use of water resources in Brazil is regulated by Federal Law No. 9,433/1997, which establishes the National Water Resources Policy. This law requires prior authorization for any use of water resources that may impact the natural system, quantity, or quality of water in a given body of water. As a result, our water use-including water supply and effluent discharge-requires a water grant (outorga de uso da água) or, in specific cases, a formal waiver, provided that all legal requirements are met. The authority responsible for issuing the water grant depends on the domain of the water body, for example, whether it is under federal or state domain. If the water body falls under federal domain, ANA is responsible, and the legal requirements are outlined in Federal Law No. 9,433/1997 and ANA’s Resolution No. 1,941/2017. For water bodies under the domain of the State of São Paulo, SP Águas is the public authority which grants the authorization, and the legal requirements are outlined in the State Water Policy, Law No. 7,663/1991, and in the State Supplementary Law (Lei Complementar) No. 14,013/2025, as well as DAEE’s Ordinance No. 1,630/2017. Noncompliance with the applicable law regarding the use of water resources may result in environmental liabilities, such as administrative infraction and environmental crime, without prejudice to the obligation to indemnify eventual damage caused to the environment. At the administrative federal level, sanctions can range from simple warning, the application of fines ranging from R$50.00 to R$50.0 million and the prohibition of the source of use of water resources, which may indirectly impact related developed activities. This amount can be doubled in the event of a repeat offense. In addition, water pollution may subject the offender to fines ranging from R$50.00 to R$50.0 million. State law establishes the basic principles governing the use of water resources in the State of São Paulo in accordance with the State constitution. These principles include: • rational utilization of water resources, ensuring that their primary use is to supply water to the population; • optimizing the economic and social benefits resulting from the use of water resources; 61 Table of Contents • protection of water resources against actions which could compromise current and future use; • defense against critical hydrological events which could cause risks to the health and safety of the population or economic and social losses; • development of hydro-transportation for economic benefit; • development of permanent programs of conservation and protection of underground water against pollution and excessive exploitation; and • prevention of soil erosion in urban and rural areas, with a view to protecting against physical pollution and silting of water resources. State Law No. 12,183/2005 established the basis for charging for the use of the water resources under the domain of the State of São Paulo. The criteria for calculating the amount of the charge are proposed by the river basin committees and must be submitted for approval to the state water resources council and formalized by a specific decree issued by the Governor of the State of São Paulo. In accordance with current legislation, the river basin committees prepare and approve rules and criteria for the implementation of the charges, and the National Water Agency, SP Águas and the Basin Agencies (Agências da Bacia) are authorized to charge users, such as us, for the water collection or discharge of effluents into water bodies. The State of São Paulo has a total of 21 river basin committees, four of which operate in basins that extend across more than one state, classified as interstate. Charging for the use of water resources has already been implemented by all river basin state committees since 2024. For the year ended December 31, 2025, we paid approximately R$98.1 million for the collection and discharge into federal and state-controlled rivers. Water Quality Annex XX of Consolidation Ordinance No. 5, amended by Ordinance No. 888 of May 2021, issued by the Ministry of Health of the federal government, provides the standards for potable water for human consumption and establishes potability standards in Brazil. It also outlines rules for sampling and limits related to substances that are potentially hazardous to human health. In compliance with Brazilian law, the physical-chemical, organic and bacteriological analyses carried out for water quality control must follow national and international standards, such as: Standard Methods for the Examination of Water and Wastewater, amongst others. Federal Decree No. 5,440/2005 determines the disclosure of water quality information to consumers. We have been complying with this regulation by publishing the required information on monthly bills and annual reports delivered to all consumers that we serve. Environmental Regulation The development, implementation and operation of water and sewage systems are subject to federal, state and local laws and regulations on environmental and water-resource protection. CONAMA and IBAMA are the primary federal agencies overseeing activities with potential environmental impacts. At state level, CETESB is responsible for controlling, supervising, monitoring and licensing of polluting activities. Environmental control and planning in Brazil are governed by a combination of federal and state laws and regulations. These legal instruments establish guidelines for pollution control, water resource management, and environmental licensing. 62 Table of Contents Federal Laws and Regulations We are subject to the following federal environmental laws and regulations in our operations, among others: • Supplementary Law No. 140/2011: Regulates: (i) environmental licenses, (ii) federal, state, and municipal jurisdiction over environmental matters, (iii) activities subject to licensing, and (iv) environmental impact studies and reports. • Brazilian Forestry Code (Law No. 12,651/2012): Requires the preservation of permanent protection areas (APPs), particularly around water springs and reservoirs. Recognizes these areas as essential for: (i) water security, (ii) geological stability, (iii) biodiversity conservation, and (iv) soil nutrition. • CONAMA Resolution No. 05/1988: Requires environmental licensing for sanitation projects that significantly alter the environment. • CONAMA Resolution No. 357/2005, amended by Resolution No. 430/2011: Establishes standards for the discharge of effluents into water bodies. • ANA Resolution No. 236/2024: Establishes updated rules for the use of federal water resources, including the procedures for regularization, revision, and suspension of water-use rights. Defines risk levels for economic activities, identifies insignificant uses and non-outorga interventions, and sets users’ obligations. • Federal Law No. 15,190/2025 — General Environmental Licensing Law: Establishes nationwide rules for environmental licensing, standardizing procedures across federal, state, and municipal levels. Maintains the traditional three-stage licensing structure (preliminary, installation, and operation licenses) and introduces additional licensing modalities — the Environmental Single License (LAU), the License by Adhesion and Commitment (LAC), and the Special Environmental License (LAE) — allowing procedures to be adapted according to the scale, impact, and risk of each activity, while maintaining environmental protection standards. • Federal Law No. 9,605/1998 — Environmental Crimes Law: Defines administrative, civil, and criminal sanctions for conduct harmful to the environment, establishing liability for individuals and legal entities and enabling penalties such as fines, restrictions of rights, and suspension of activities. State Laws and Regulations (São Paulo): We are subject to the following state environmental laws and regulations in our operations, among others: • State Law No. 997/1976, regulated by Decree No. 8,468/1976 and its amendments: (i) establishes environmental pollution control mechanisms and (ii) defines standards for effluent discharge at the state level. • State Law No. 9,509/1997, regulated by State Decree No. 47,400/2002: Defines São Paulo’s state environmental policy. • DAEE (São Paulo State Department of Water and Electricity) Ordinance No. 1,630/2017: Governs the concession of water-use rights and interventions in water resources at the state level. • CETESB Board Decision No. 03/2014/P, as amended: establishes procedures and criteria for environmental licensing in the State of São Paulo, including licensing modalities (Preliminary License – LP, Installation License – LI, and Operating License – LO) and guidelines for the filing and review of administrative proceedings; • CETESB Board Decision No. 217/2014/I/C: sets forth criteria for the classification of projects and activities subject to environmental licensing, including classification based on pollution potential and scale; and 63 Table of Contents • CETESB Board Decision No. 038/2017/C: consolidates administrative procedures applicable to environmental licensing, including guidelines for technical review and the processing of administrative proceedings. Our reservoirs that were operational before the enactment of the laws and regulations described above are exempt from developing a PACUERA (Environmental Plan for the Conservation and Use of the Surroundings of the Reservoir), as such obligation applies only to reservoirs established thereafter. Environmental Licensing Environmental licensing in Brazil is governed by federal, state, and local laws, requiring a license for activities that (i) use natural resources, (ii) are effectively or potentially polluting, or (iii) can cause environmental damage. Federal Law No. 6,938/1981 (National Environmental Policy) mandates prior licensing, while Supplementary Law No. 140/2011 divides licensing responsibilities among IBAMA, state, and municipal authorities. Federal Law No. 15,190/2025 (General Environmental Licensing Law) now establishes nationwide rules for environmental licensing, standardizing procedures and introducing new licensing modalities and criteria across all government levels. • IBAMA: Licenses activities across multiple states, in federal areas, or involving nuclear energy. • Municipal authorities: License activities with strictly local impact. • State environmental agencies: Handle all other licensing. The enactment of Law No. 15,190/2025 (Brazilian General Environmental Licensing Law – “LGLA”) has significantly restructured the environmental licensing framework in Brazil. While maintaining the traditional three-stage licensing model (preliminary, installation and operation licenses) as a reference, the LGLA introduced new licensing modalities, including the Single Environmental License (Licença Ambiental Única – “LAU”), the License by Adhesion and Commitment (Licença por Adesão e Compromisso – “LAC”), the Special Environmental License (Licença Ambiental Especial – “LAE”), and the Corrective Operating License (Licença de Operação Corretiva – “LOC”), aimed at simplifying procedures and tailoring licensing requirements to the nature, scale and risk level of each project. The LGLA applies to all entities within the Brazilian National Environmental System (Sistema Nacional do Meio Ambiente – “Sisnama”), in accordance with the allocation of competencies established under Law No. 140/2011. Notwithstanding its entry into force, certain provisions of the LGLA—particularly those related to exemptions from environmental licensing— are currently subject to constitutional review before the Brazilian Supreme Federal Court (Supremo Tribunal Federal – “STF”), in the context of Direct Actions of Unconstitutionality (Ações Diretas de Inconstitucionalidade – “ADIs”) Nos. 7,913, 7,916 and 7,919, and their application may be subject to adjustments or interpretative limitations. For the sanitation sector, the LGLA establishes a differentiated regulatory framework, including procedural simplification and priority in the analysis of water supply and wastewater treatment projects. Pursuant to Article 10, §2, such systems and facilities are, as a rule, exempt from environmental licensing until the universalization targets set forth in Federal Law No. 11,445/2007 are achieved, without prejudice to the requirement to obtain water use rights for effluent discharge. Projects with significant environmental impact require an Environmental Impact Assessment and Environmental Impact Report (Estudo de Impacto Ambiental — “EIA” and Relatório de Impacto Ambiental — “RIMA”), with a minimum 0.5% environmental offset. The licensing process typically consists of three stages: preliminary license, installation license, and operation license. Environmental licenses must be periodically renewed, with renewal requests filed up to 120 days prior to the expiration date. Non-compliance with license conditions may lead to administrative sanctions, including fines or license revocation. Operating without a valid environmental license constitutes an administrative infraction and environmental crime, subject to fines of up to R$50.0 million and joint and several liability for environmental damage, regardless of fault or intent. 64 Table of Contents In the State of São Paulo, CETESB oversees licenses and pollution control. CETESB Executive Officers’ Resolution No. 012/2022/C launched a licensing regularization program for water treatment plants and sewage treatment plants, to be completed by 2027. We have implemented corporate programs for obtaining and maintaining licenses, covering water treatment plants and sewage pumping stations, as well as for environmental recovery commitment terms, including forest restoration and environmental compensation, aligned with CETESB Resolution No. 012/2022/C. Sewage Requirements In the State of São Paulo, effluent must meet applicable requirements before discharge into the public sewage system. Effluent treated at our sewage treatment facilities must comply with: (i) effluent limitation guidelines and (ii) water quality standards applicable to the receiving water bodies, as established by federal and state legislation. CETESB is authorized to: (i) monitor effluent discharges into water bodies and (ii) issue environmental licenses to polluting sources, including sewage treatment plants. Both state and federal water resource legislation establish fees for the discharge of treated effluents into water bodies, which are already in effect in most river basins. Environmentally Protected Areas We manage and protect approximately 49,000 hectares within conservation units, as defined by Federal Law No. 9,985/2000. The Cantareira System management plan for its Environmental Protection Area (Área de Proteção Ambiental — “APA”) was formally approved by Decree No. 65,244/2020. This structured approach ensures the preservation and sustainable management of critical water resources in compliance with federal and state environmental legislation. Environmental Liabilities Environmental liability in Brazil is comprehensive and strict, applying to individuals and legal entities that cause direct or indirect environmental damage through action or omission. It is regulated under civil, administrative, and criminal law, ensuring that environmental harm is remediated, sanctioned, and prevented. Pursuant to Federal Law No. 6,938/1981 (National Environmental Policy), Brazil adopts a strict liability standard for civil environmental liability, meaning (i) liability is applied regardless of fault or intent, and (ii) evidence of a causal link between the damage and an enterprise or activity is sufficient to trigger the obligation to remediate the environmental harm. Environmental civil liability is joint and several, meaning all parties — individuals and legal entities — directly or indirectly involved in the activity that caused environmental damage can be held fully liable. If multiple parties are responsible, the financially strongest party may be required to bear the full remediation cost but may later seek recourse against other responsible parties through: (i) contractual agreements or (ii) judicial action demonstrating the involvement of others. Courts may pierce the corporate veil when a party obstructs environmental remediation, even without proof of fraud or misuse of the corporate structure. The mere failure to remediate environmental damage is sufficient to justify holding shareholders personally liable in the civil sphere. There is no cap on the amount courts may award for: (i) repairing environmental damage or (ii) compensation if the damage is deemed irreparable. A recent precedent from the Brazilian Federal Supreme Court ("STF") abolished the statute of limitations for lawsuits seeking reparation or compensation for environmental damage. Under Federal Decree No. 6,514/2008, any action or omission that violates applicable environmental regulations constitutes an environmental administrative infraction, even if no actual environmental damage has occurred. Administrative sanctions and penalties vary based on the severity of the infraction and the economic capacity of the offender. Sanctions may include: (i) fines (single or daily), (ii) warnings, (iii) restriction of rights, (iv) seizure of products and byproducts, (v) closure of facilities, (vi) prohibition from contracting with public entities, (vii) suspension of permits, (viii) loss of financial or fiscal benefits, and (ix) full or partial suspension of activities. 65 Table of Contents Legal entities can be held criminally liable for environmental offenses under Federal Law No. 9,605/1998. If convicted, penalties may include: (i) fines, (ii) temporary bans on rights, (iii) partial or total suspension of activities, and (iv) other sanctions, independent of any administrative penalties or civil liabilities related to the same facts. The criminal liability of legal entities does not exclude the criminal liability of natural persons (e.g., officers, board members, or technical staff) who authorized, participated in, or facilitated the offense. Scope of Business In connection with the scope of our services, State Supplementary Law No. 1,025/2007 amended State Law No. 119/1973 and expanded the range of services that we may provide, including urban rainwater drainage and management, urban cleaning and solid waste management, as well as power generation, storage, conservation, and sales activities, for our own or third-party use. C. Organizational Structure Not applicable. D. Property, Plant and Equipment Our principal property, plant and equipment comprise administrative facilities which are stated at historical costs less depreciation. The reservoirs, water treatment facilities, water distribution networks consisting of water pipes, water transmission lines, water connections and water meters, sewage treatment facilities, and sewage collection networks consisting of sewer lines and sewage connections are recorded as contract assets and intangible assets (concession assets). As of the date of this annual report, we operate 214 water treatment facilities, 690 simplified water treatment facilities and 641 sewage treatment facilities, including eight ocean outfalls, as well as 18 water quality control laboratories. As of December 31, 2025, the total net book value of our property, plant and equipment, intangible assets and contract assets and other concession assets was R$62,401.8 million. All of our material properties are located in the State of São Paulo.
The following management’s discussion and analysis of financial condition and results of operations should be read in conjunction with our audited Consolidated Financial Statements included elsewhere in this annual report. The Consolidated Financial Statements included elsewhere…
The following management’s discussion and analysis of financial condition and results of operations should be read in conjunction with our audited Consolidated Financial Statements included elsewhere in this annual report. The Consolidated Financial Statements included elsewhere in this annual report have been prepared in accordance with IFRS Accounting Standards. This annual report contains forward-looking statements that involve risks and uncertainties. Our actual results may differ materially from those discussed in the forward-looking statements as a result of various factors, including, without limitation, those set forth in “Item 3.D. Risk Factors.” In the following discussion, references to increases or decreases in any period are made by comparison with the corresponding prior period, except as the context otherwise indicates. All financial information for the years ended December 31, 2025, 2024, and 2023 was prepared on a consolidated basis. 66 Table of Contents A. Operating Results As of December 31, 2025, we operated water and sewage systems in the State of São Paulo, including in the city of São Paulo, Brazil’s largest city. Our operations extended into a total of 375 municipalities, or 58% of all municipalities in the state. We also provided water services on a wholesale basis to two municipalities located in the São Paulo metropolitan region in which we did not operate water distribution systems. Our capital expenditure program is our most significant liquidity and capital resource requirement. Since December 11, 2023, we have provided water and sewage services in Olímpia through our wholly-owned subsidiary Sabesp Olímpia S.A. As a result, we began presenting our financial information on a consolidated basis starting with our 2023 Consolidated Financial Statements. Prior to that date, we did not have any subsidiaries whose results we consolidated on a line-by-line basis. Factors Affecting our Results of Operations General Factors Affecting our Business Our results of operations and financial condition are generally affected by our ability to raise tariffs, control costs and improve productivity, general economic conditions in Brazil and abroad, climate conditions, impacts of regulation for sanitation services, global and local catastrophes and health epidemics, and extreme weather events. In the event of a significant devaluation of the real in relation to the U.S. dollar or other currencies, our ability to meet our foreign currency-denominated obligations could be adversely affected because our tariff revenue and other sources of income are denominated solely in reais. In addition, as we have debt denominated in foreign currencies, any significant devaluation of the real will increase our financial expenses as a result of foreign exchange losses that we must record. Accordingly, a devaluation of the real may adversely affect us and the market price of our common shares or ADSs. In December 2023, our Board of Directors approved our Hedging Policy, which is available on our website but is not incorporated herein. During the year ended December 31, 2025, we entered into derivative instruments (plain vanilla swaps), with expiration dates ranging from 2030 to 2048, to fully protect us against a devaluation of the real against the U.S. dollar, the Yen, and the Euro. For more information with respect to our foreign currency risk, see Note 5.1(a) to our 2025 Consolidated Financial Statements. Effects of Tariff Increases Our results of operations and financial condition are dependent on tariff increases for our water and sewage services. Since the enactment of the Basic Sanitation Law in 2007, regulatory agencies are responsible for setting, adjusting and reviewing tariffs, taking into consideration, among other factors: • anti-inflation measures enacted by the federal government from time to time; • impacts of health epidemics such as COVID-19; and • when necessary, the readjustment to maintain the original balance between each party’s obligation and economic gain (equilíbrio econômico-financeiro) under the agreement. Readjustment of our tariffs continues to be set annually and depends on the parameters established by the Basic Sanitation Law, the URAE-1 Concession Agreement and ARSESP, except for Olímpia, which is regulated by ARES-PCJ under the terms of the Olímpia Concession Agreement. The guidelines also establish procedural steps and the terms for annual adjustments. The annual adjustments must be announced 30 days prior to the effective date of the new tariffs. For more information, see “Item 4.B. Business Overview — Tariffs.” Since our Privatization, a distinction exists between the equilibrium tariff calculated by ARSESP and the tariff applied to consumers. As a result, tariff increases perceived by users may be lower than the underlying economic adjustments, with the difference covered by the FAUSP, a mechanism designed to smooth tariff implementation and reduce volatility. 67 Table of Contents The following table sets forth, for the years indicated, the percentage increase in our tariffs as compared to three inflation indexes: Year ended December 31, 2025 2024 2023 Increase in average tariff(1) 6.47 % 6.45 % 9.56 % Inflation – IPC – FIPE 3.83 % 4.68 % 3.15 % Inflation – IPCA 4.26 % 4.83 % 4.62 % Inflation – IGP-M (1.05) % 6.54 % (3.18) % (1) See “Item 4.B. Business Overview — Tariffs” for additional information on tariff increases. On April 6, 2023, ARSESP published Resolution No. 1,394/2023 related to the Extraordinary Tariff Review and Resolution No. 1,395/2023, which presented the new tariffs and authorized us to apply a total tariff readjustment of 9.5609% to our current tariffs. This tariff adjustment became effective on May 10, 2023. On April 8, 2024, ARSESP published Resolution No. 1,514, which authorized a total tariff readjustment of 6.4469% to our tariffs, which was in force between May 10, 2024 and July 22, 2024. From July 23, 2024, with the commencement of Concession Agreement No. 01/2024, the new tariffs published by ARSESP came into effect through Resolution No. 1,539/2024, including discounts on the tariffs in force at the time as authorized by the Government of the State of São Paulo. On December 1, 2025, ARSESP published Resolution No. 1,748/2025 which approved the equilibrium tariff related to the 1st Tariff Readjustment and Resolution No. 1,749/2025, which presented the new tariffs and authorized us to apply a total tariff readjustment of 6.47% to our current tariffs. This tariff adjustment became effective on January 1, 2026. Effects of Brazilian Economic Conditions As a company with all of its operations in Brazil, our results of operations and financial condition are affected by general economic conditions in Brazil, particularly by the level of economic activity and the inflation rate. For example, the general performance of the Brazilian economy may affect our cost of capital, and inflation may affect our costs and margins. The Brazilian economic environment has been characterized by significant variations in economic growth rates. However, as our services are viewed as essential, our sales revenue demonstrates relative stability under normal conditions. General Economic Conditions In 2023, Brazilian GDP increased 2.9% compared to 2022. Brazil’s trade surplus in 2023 was US$98.8 billion and at year-end the country had US$355.0 billion in currency reserves. The average unemployment rate in Brazil in 2023 was 7.8%. In 2024, Brazilian GDP increased 3.4% compared to 2023. Brazil’s trade surplus for the year ended December 31, 2024 was US$74.6 billion and at year-end the country had US$329.7 billion in currency reserves. The average unemployment rate in Brazil for the year ended December 31, 2024 was 6.6%. In 2025, Brazilian GDP increased approximately 2.5% compared to 2024, as estimated based on the IBC-BR economic activity index published by the Central Bank of Brazil. Brazil’s trade surplus for the year ended December 31, 2025 was US$60.0 billion and at year-end the country had US$358.2 billion in currency reserves. The average unemployment rate in Brazil for the year ended December 31, 2025 was 5.1%. Interest Rates As a monetary policy instrument of the federal government, the Selic rate influences the behavior of other interest rates in the country, including rates related to indebtedness denominated in local currency. The Selic rate was 13.75% in the first half of 2023, decreased to 10.50% in August 2024, and was gradually increased thereafter. As of the date of this annual report., the Selic rate is 14.75%. Inflation Inflation affects our financial performance by increasing our tariffs, costs of services rendered, and operating expenses. Part of our real-denominated debt is directly indexed to account for the effects of inflation. Additionally, we are exposed to the mismatch between the inflation adjustment indices of our loans and financing and those of our receivables. 68 Table of Contents Inflation adjustments derive from collections from or payments to third parties, as contractually required by law or court decision, and are recognized on an accrual basis. Inflation adjustments included in these agreements and decisions are not considered embedded derivatives, as they are deemed to be inflation adjustments for our purposes. See Notes 5.1, 17 and 32 of our 2025 Consolidated Financial Statements for the impacts of inflation adjustments on our financial performance and debt. Currency Exchange Rates We had total foreign currency-denominated indebtedness of R$10,632.3 million as of December 31, 2025, of which R$371.7 million relates to the current portion of our long-term foreign currency-denominated obligations. As of December 31, 2025, we have fully hedged our currency exposure, including interest payments. The following table shows the fluctuation of the real against the U.S. dollar, the period-end exchange rates, and the average exchange rates as of or for the years indicated: Year ended December 31, 2025 2024 2023 (in reais, except percentages) Depreciation (appreciation) of the real versus U.S. dollar(1) (11.1) % 27.9 % (7.21) % Period-end exchange rate – US$1.00 5.5024 6.1923 4.8413 Average exchange rate – US$1.00(2) 5.5855 5.3890 4.9953 (1) Represents the comparison with period-end exchange rate. Source: Central Bank. (2) Represents the average for period indicated. The following table shows the fluctuation of the real against the Yen, the period-end exchange rates, and the average exchange rates as of or for the years indicated: Year ended December 31 2025 2024 2023 (in reais, except percentages) Depreciation (appreciation) of the real versus Yen (1) (11.0)% 15.3% (13.52)% Period-end exchange rate – ¥1.00 0.0351 0.0395 0.0342 Average exchange rate – ¥1.0 (2) 0.0374 0.0356 0.0356 (1) Represents the comparison with period-end exchange rate. Source: Central Bank. (2) Represents the average for period indicated. The following table shows the fluctuation of the real against the Euro, the period-end exchange rates, and the average exchange rates as of or for the years indicated Year ended December 31 2025 2024 2023 (in reais, except percentages) Depreciation (appreciation) of the real versus Euro (1) 0.51% 20.27% (3.91)% Period-end exchange rate – €1.00 6.4692 6.4363 5.3516 Average exchange rate – €1.0 (2) 6.3095 5.8340 5.4023 (1) Represents the comparison with period-end exchange rate. Source: Central Bank. (2) Represents the average for period indicated. In the years ended December 31, 2025, 2024, and 2023, we did not enter into any forward exchange transactions. During the year ended December 31, 2025, we entered into derivative instruments (plain vanilla swaps), with expiration dates ranging from 2030 to 2048, to fully protect us against a devaluation of the real against the U.S. dollar, the Yen, and the Euro. For more information on exchange rates, see “Item 3.D. Risk Factors — Risks Relating to Brazil — Exchange rate instability and developments and the perception of risk in other countries, especially in the United States and in emerging market countries, may adversely affect us, our foreign currency denominated debt and the market price of our common shares or ADSs and our ability to service our foreign currency denominated obligations,” “Item 5.B. Liquidity and Capital Resources—Indebtedness Financing—Financial Covenants,” and Note 5.1 of our 2025 Consolidated Financial Statements. 69 Table of Contents Effects of Extreme Weather Events In February 2023, there were torrential rains on the northern coast of the State of São Paulo, especially in the municipality of São Sebastião, where we operate. Within 24 hours, 683mm of rain fell in the municipality of São Sebastião. As a result, our water treatment plants in the region were damaged and the water supply was interrupted for a few days due to the inability to store water immediately and a lack of electricity. If similar incidents, or incidents that involve the interruption of power supplies to our facilities, occur in the future or become more frequent, these events may have a material adverse effect on our results of operations and financial condition. Extreme events such as heat waves and torrential storms can interrupt the electricity supply at our water pumping and treatment plants due to trees falling on electricity distribution networks, which could prevent the treatment of water and potentially its supply to our customers. In addition, torrential rain destabilizes the soil and can damage our water distribution networks. In 2025, the Southeast region of Brazil, where we operate, experienced one of the driest periods of the past decade. This extreme climatic event adversely affected the storage levels of our water sources. In coordination with the federal regulator, the National Water and Basic Sanitation Agency (Agência Nacional de Águas — “ANA”), and the state regulator ARSESP (Agência Reguladora de Serviços Públicos do Estado de São Paulo) we have been conducting daily monitoring of the reservoirs comprising the Integrated Metropolitan System (“SIM”). The SIM, established following the 2014–2015 water crisis, consists of seven interconnected production systems, providing operational flexibility by allowing multiple supply alternatives across São Paulo and the broader Metropolitan Region (RMSP). The monitoring framework adopted by the State Government of São Paulo is structured into seven response tiers, determined by reservoir levels. Each tier establishes the degree of required hydrological protection measures, including public awareness initiatives and nighttime demand management protocols intended to reduce network losses during low consumption periods. As of February 2026, the SIM was operating under Tier 3 — classified as a cautionary scenario — which entails extended nighttime demand management (10 hours) and reinforced communication efforts regarding the efficient use of water. Considering the existing structure of the SIM, which enables the transfer of treated water between producing systems, we are able to implement measures to re-establish and maintain regularity in the distribution of water to our customers. Since the 2014–2015 water crisis, we have consistently invested in expanding the SIM’s streamflow capacity. Between 2015 and 2025, system capacity increased by 14.2 m³/s through interconnection projects and the development of the São Lourenço production system. Additional resilience investments scheduled for 2026–2030, totaling R$5.9 billion, are expected to add a further 12.8 m³/s to system capacity, including 5.8 m³/s anticipated by 2027. We remain focused on diversifying supply sources, enhancing system integration, and strengthening overall water security resilience. However, if similar extreme weather events occur in the future or become more frequent, these events could have an adverse effect on our operating results and financial condition. For more information, see “Item 3.D. Risk Factors — Risks Relating to Environmental Matters and Physical and Climate Transition Risks — Droughts, such as the 2014 – 2015 water crisis, can cause a material impact on consumption habits and, consequently, on our business, financial condition or results of operations.” Critical Accounting Estimates and Judgments We make estimates and judgments concerning the future. The resulting accounting estimates will, by definition, seldom equal the related actual results. For information on our critical accounting estimates and judgments, see Note 6 to our 2025 Consolidated Financial Statements. 70 Table of Contents Certain Transactions with our previous Controlling Shareholder Reimbursement due from the State Reimbursement due from the State of São Paulo for pensions paid represents supplementary pensions (G0) that we pay, on behalf of the State of São Paulo, to former employees of state-owned companies which merged to form our company. These amounts must be reimbursed to us by the State of São Paulo, as the primary obligor. In November 2008, we entered into the third amendment to the agreement with the State of São Paulo relating to payments of pension benefits made by us on its behalf. The State of São Paulo acknowledged that it owed us an outstanding balance of R$915.3 million as of September 30, 2008, relating to payments of pension benefits made by us on its behalf. We provisionally accepted, but it is not recognized in our books, the reservoirs in the Alto Tietê production system as partial payment in the amount of R$696.3 million, subject to the transfer of the property rights of these reservoirs to us. See Note 11 to our 2025 Consolidated Financial Statements included in this annual report and “Item 7. Major Shareholders and Related Party Transactions.” On March 18, 2015, we, the State of São Paulo and DAEE, with the intervention of the Department of Sanitation and Water Resources, executed an agreement for R$1,012.3 million, consisting of R$696.3 million in principal amount and R$316.0 million in monetary adjustment of the principal through February 2015. As of December 31, 2025 and 2024, the amounts not recognized related to pension benefits paid by us on behalf of the State of São Paulo totaled R$1,808.6 million and R$1,685.5 million, respectively. As a result, we also recognized the obligation related to pension benefits, maintained with the beneficiaries and pensioners of G0. As of December 31, 2025 and 2024, the pension benefit obligations of G0 totaled R$2,140.2 million and R$1,931.1 million, respectively. For detailed information on the pension benefit obligations refer to Note 25 to our 2025 Consolidated Financial Statements included in this annual report. Accounts Receivable from the State of São Paulo for Water and Sewage Services Rendered Certain of these accounts receivable have been overdue for a long period. We have entered into agreements with the State of São Paulo with respect to these accounts receivable. For more information on these agreements, see Note 11 to our 2025 Consolidated Financial Statements included in this annual report. Results of Operations The following table sets forth, for the years indicated, certain items from our income statements of operations, each expressed as a percentage of operating revenue: (in million of R$, except percentages) Year ended December 31, 2025 2024 2023 Operating revenue 38,092.1 100.0 % 36,145.5 100.0 % 25,572.1 100.0% Operating costs (23,991.7) (63.0) % (16,603.1) (45.9) % (16,051.9) (62.8) % Gross profit 14,100.4 37.0 % 19,542.4 54.1 % 9,520.2 37.2 % Selling expenses (743.3) (2.0) % (917.6) (2.5) % (984.1) (3.8) % Allowance for doubtful accounts (62.1) (0.2) % (557.8) (1.5) % (652.9) (2.6) % Administrative expenses (1,018.3) (2.7) % (2,311.4) (6.4) % (1,597.5) (6.2) % Other operating income (expenses), net 274.7 0.7 % (280.5) (0.8) % 27.9 0.1 % Equity accounting 48.2 0.1 % 35.3 0.1 % 32.4 0.1 % Profit from operations before financial income (expenses) 12,599.6 33.1 % 15,510.5 42.9 % 6,346.0 24.8 % Financial income/(expenses), net (897.8) (2.4) % (1,867.7) (5.2) % (1,592.0) (6.2) % Profit before income tax and social contribution 11,701.9 30.7 % 13,642.8 37.7 % 4,754.0 18.6 % Income tax and social contribution taxes (current and deferred) (3,239.8) (8.5) % (4,063.2) (11.2) % (1,230.5) (4.8) % Profit for the year 8,462.1 22.2 % 9,579.6 26.5 % 3,523.5 13.8 % 71 Table of Contents Year Ended December 31, 2025 Compared to Year Ended December 31, 2024 Operating revenue Operating revenue for the year ended December 31, 2025 increased by R$1,946.6 million, or 5.4%, to R$38,092.1 million from R$36,145.5 million in the year ended December 31, 2024. Operating revenue, excluding construction revenue, the impact of interest rate adjustments on the bifurcated financial asset using the IPCA index, for the year ended December 31, 2025 increased by R$487.2 million, or 2.2%, to R$22,213.0 million in the year ended December 31, 2025 from R$21,725.8 million in the year ended December 31, 2024. Construction revenue was R$14,437.4 million for the year ended December 31, 2025 compared to R$6,225.9 million in the year ended December 31, 2024. The main factors that led to the increase were: • 3.3% in net price: 2.3% carry over and 1.0% due to removal of discounts for large clients; • 1.9% in billed volume: New units (+1.6%) and increased consumption (+0.3%); • (0.8%) in mix: growth in units with access to subsidized rates; • (2.1%) FAUSP: in 2024 FAUSP began only in the 2nd half and the rate review occurred in August 2025. Operating costs Our operating costs increased by R$7,388.6 million, or 44.5%, to R$23,991.7 million for the year ended December 31, 2025 from R$16,603.1 million in the year ended December 31, 2024. As a percentage of operating revenue, operating costs increased to 63.0% for the year ended December 31, 2025 from 45.9% in the year ended December 31, 2024. The increase in operating cost was mainly due to: • an increase of R$8,351.5 million in construction costs due to higher investments in 2025; • an increase of R$225.7 million in costs with services, mainly due to environmental compensation and IT investments and, partially offset by, • a decrease of R$456.3 million in general expenses, mainly because we had anticipated contributions to municipal sanitation funds in 2024 pursuant to the Concession Agreement for URAE-1; • a decrease of R$222.4 million in costs with salaries, payroll charges and benefits and pension plan obligations, mainly due to the 11% decrease in the average number of employees – as a result of the Incentivized Dismissal Program (“PDI”). Gross Profit As a result of the factors discussed above, gross profit decreased by R$5,442.0 million, or 27.8%, to R$14,100.4 million for the year ended December 31, 2025 from R$19,542.4 million in the year ended December 31, 2024. As a percentage of operating revenue, our gross profit margin decreased to 37.0% for the year ended December 31, 2025 from 54.1% in the year ended December 31, 2024, mainly due to a decrease of the financial asset of the concession operating revenue by R$7,474.9 million. For further information about our financial asset net revenue, see Note 15 to our 2025 Consolidated Financial Statements. Selling Expenses Selling expenses decreased by R$174.3 million, or 19.0%, to R$743.3 million for the year ended December 31, 2025 from R$917.6 million in the year ended December 31, 2024. As a percentage of operating revenue, selling expenses were 2.0% for the year ended December 31, 2025 compared to 2.5% for the year ended December 31, 2024. The main reasons for the decrease in selling expenses were: • a decrease of R$96.5 million with general expenses; 72 Table of Contents • a decrease of R$72.1 million in costs with salaries, payroll charges and benefits and pension plan obligations, mainly due to the decrease in the average number of employees; Allowance for Doubtful Accounts Our allowance for doubtful accounts decreased by R$495.7 million, or 88.9%, to R$62.1 million for the year ended December 31, 2025 from R$557.8 million in the year ended December 31, 2024, mainly due to a reversal of expected credit loss provisions (PECLD) due to the recognition of court-ordered payments (precatórios) to São Paulo City Hall. Administrative Expenses Administrative expenses decreased by R$1,293.1 million, or 55.9%, to R$1,018.3 million for the year ended December 31, 2025 from R$2,311.4 million in the year ended December 31, 2024. The main reasons for the decrease in administrative expenses were: • a decrease of R$823.2 million with general expenses, due to settlements resulting from judicial proceedings; and • a decrease of R$258.1 million with other expenses (general supplies, outsources services, electricity, depreciation and amortization and tax expenses), due to the agreement entered into between SABESP and AAPS (Sabesp’s Association of Retirees and Pensioners); • a decrease of R$211.9 million in costs with salaries, payroll charges and benefits and pension plan obligations, mainly due to the decrease in the average number of employees. The agreement entered into between us and AAPS, regarding financial compensation for 60 months for the VIVEST health plan operator regarding the migration of retirees, former employees, pensioners, and dependents between health plans is recorded in this line. For more information, see Note 31 to our 2025 Consolidated Financial Statements included in this annual report. Other Operating Income (Expenses), Net Other operating income (expenses), net, was the income of R$274.7 million for the year ended December 31, 2025 compared to expense of R$280.5 million in the year ended December 31, 2024, a variation of R$555.2 million. Other operating income consists of gains and losses from sales of property, plant and equipment, sale of contracts awarded in public bids, right to sell electricity, indemnities and reimbursement of expenses, fines and collaterals, property leases, reuse of water, PURA projects and services, net of COFINS and PIS. Other operating expenses consist mainly of derecognition of concessions assets due to obsolescence, discontinued construction works, unproductive wells, projects considered economically unfeasible, losses on property, plant and equipment and recognition and reversal of estimated losses with asset indemnification. In 2025, the result was impacted by the recognition of extemporaneous tax credits of R$368.5 million. Financial Income/(Expenses), Net The financial income/(expenses), net, decreased by R$969.9 million, resulting in a net expense of R$897.8 million for the year ended December 31, 2025, compared to a net expense of R$1,867.7 million in the year ended December 31, 2024. As a percentage of operating revenue, the net financial income/(expenses), net, represented 2.4% for the year ended December 31, 2025, compared to 5.2% in the year ended December 31, 2024. This decrease was mainly due to an extemporaneous effect recognized in 2025, recorded in the inflation adjustments – gains line item, related to the recognition of R$1.5 billion in monetary restatement of registered warrants. Profit before income tax and social contribution As a result of the factors discussed above, profit before income tax and social contribution decreased by R$1,940.9 million, to R$11,701.9 million for the year ended December 31, 2025 from R$13,642.8 million in the year ended December 31, 2024. As a percentage of operating revenue, our profit before income tax and social contribution decreased to 30.7% for the year ended December 31, 2025 compared to 37.7% in the year ended December 31, 2024. 73 Table of Contents Income and Social Contribution Taxes (Current and Deferred) Income and social contribution taxes (current and deferred) expense decreased by R$823.4 million, or 20.3%, to R$3,239.8 million for the year ended December 31, 2025, compared to R$4,063.2 million for the year ended December 31, 2024. This decrease mainly reflects the effect of the financial asset recognized in 2024, resulting from the contract with URAE-1, which continued to impact the year-over-year comparison. Profit for the year As a result of the factors discussed above, our profit decreased by R$1,117.5 million, or 11.7%, to R$8,462.1 million for the year ended December 31, 2025 from R$9,579.6 million in the year ended December 31, 2024. As a percentage of operating revenue, our profit for the year decreased to 22.2% for the year ended December 31, 2025, from 26.5% in the year ended December 31, 2024. Year Ended December 31, 2024 Compared to Year Ended December 31, 2023 For a discussion of our results of operations for the year ended December 31, 2024 compared to the year ended December 31, 2023, see “Item 5. Operating and Financial Review and Prospects — A. Results of Operations — Year Ended December 31, 2024 Compared to Year Ended December 31, 2023 of our annual report on Form 20-F for the year ended December 31, 2024, filed with the SEC on April 30, 2025. 74 Table of Contents B. Liquidity and Capital Resources Capital Sources In order to satisfy our liquidity and capital requirements, we have primarily relied on cash provided by operating activities, long-term financings from multilateral and development banks and capital markets debts. As of December 31, 2025, we had R$4,663.2 million in cash and cash equivalents. The outstanding current indebtedness was R$5,092.8 million as of December 31, 2025, of which R$371.7 million was denominated in foreign currency. Long-term indebtedness was R$35,049.5 million as of December 31, 2025, of which R$10,260.6 million consisted of foreign currency. Management expects that we will have sufficient funds to meet our commitments and not compromise our planned investments, given the works we carried out to improve our water security and to reduce defaults, as well as the cash we generated from operations and the availability of credit lines for investments. In order to finance the constant investment needs in our infrastructure, we use third party funds to complement our own resources. We believe that we currently have sufficient sources of funds to implement our short- and medium-term strategy. Cash Flows Year ended December 31, 2025 2024 HA (%) (in millions of R$, except %) Net cash generated from operating activities 8,361.1 7,404.6 12.9% Net cash used in investment activities (15,703.6) (9,975.6) 57.4% Net cash generated from financing activities 10,323.1 3,415.2 202.3% Increase in cash and cash equivalents in the year 2,980.6 844.1 253.1 % Net Cash Generated from Operating Activities Net cash generated from operating activities is the single largest source of our liquidity and capital resources, and we expect that it will continue to be so in the future. Our net cash generated from operating activities was R$8,361.1 million and R$7,404.6 million for the years ended December 31, 2025 and 2024, respectively. The main driver of our cash flow from operating activities relates to our cash collections from customers, which is due to the nature of our business and to the fact that we are expanding our infrastructure. There was an increase in net cash generated from operating activities in the year ended December 31, 2025 of 12.9%. Net Cash Used in Investing Activities Net cash used in investing activities was R$15,703.6 million and R$9,975.6 million for the years ended December 31, 2025 and 2024, respectively. The main driver of our net cash outflow for investing activities relates to purchases of intangible assets, as required under our concession agreements, which is due to the fact that we are expanding our infrastructure and service coverage. There was an increase in net cash used in investing activities for the year ended December 31, 2025 of 57.4%. Net Cash Generated from Financing Activities Our net cash generated from financing activities was R$10,323.1 million for the year ended December 31, 2025, compared to R$3,415.2 million for the year ended December 31, 2024. The main driver of our cash flows from financing activities relates to the proceeds and repayments of loans generated to finance purchases of intangible assets related to our concession agreements, in order to support the expansion of our services and our payment of interest on capital. For the year ended December 31, 2025, (i) our funding increased by R$11,465.3 million compared to 2024 and (ii) our amortization increased by R$2,049.6 million compared to the year ended December 31, 2024. In addition, payment of interest on capital increased by R$1,434.9 million compared to the year ended December 31, 2024. 75 Table of Contents Financial Indebtedness Our total financial indebtedness (borrowings and financing – current and non-current) increased by 58.9%, from R$25,258.3 million as of December 31, 2024 to R$40,142.3 million as of December 31, 2025. In addition, during the same period, our total indebtedness denominated in foreign currency increased by 216.8%, from R$3,356.4 million as of December 31, 2024 to R$10,632.3 million as of December 31, 2025. As of December 31, 2025, we had R$35,049.5 million in long-term indebtedness outstanding (excluding the current indebtedness), of which R$10,260.6 million consisted of foreign currency, long-term debt. We had outstanding current indebtedness of R$5,092.8 million as of December 31, 2025. As of December 31, 2025, R$371.7 million of this current portion of long-term indebtedness was denominated in foreign currency. As of December 31, 2025, our S&P domestic rating was “brAAA” and our S&P global rating was “BB”. Our Moody’s national rating was “AAA.br” as of December 31, 2025, while our Fitch national rating was “AAA(bra)” and our Fitch global ratings were “BB+” (foreign currency) and “BB+” (local currency), as of the same date. Pursuant to these agreements, cash received from operations is required to pass through designated accounts. In the event of a default under the relevant agreement, such cash and future cash flows that are required to be deposited in such accounts become restricted and are subject to security interests in favor of the relevant creditor. As of December 31, 2025, a substantial portion of our monthly cash flows from operations was subject to these liens. As of that date, the total amount of our secured debt, including indebtedness benefiting from these liens, was R$6,217.9 million (R$6,096.6 million of principal and R$121.3 million related to interest and charges). For more information, see “—Indebtedness Financing—Financial Covenants—Local currency denominated indebtedness” and Note 17 to our 2025 Consolidated Financial Statements included in this annual report. The following table sets forth information on our indebtedness outstanding as of December 31, 2025: Current Noncurrent Total Final Maturity Interest Rates(1) (in R$ thousands) Denominated in local currency: Debentures 2,764,582 17,282,427 20,047,009 2026 – 2040 CDI+ 0,00% to 1.80% IPCA + 3,20% to 9.2860% 1,60% to 2.25% Brazilian Federal Savings Bank (CEF) 134,275 1,495,481 1,629,756 2025 – 2042 TR + 5% to 9.5% Brazilian National Bank for Economic and Social Development (BNDES) 259,341 564,501 823,842 2026-2035 TJLP + 1.72% to 2.18% Inter-American Development Bank (IDB) 307,349 2,680,484 2,987,833 2034 – 2036 CDI+ 0.50% CDI+ 2.70% CDI+ 20.86% International Finance Corporation (IFC) 64,450 2,645,882 2,710,332 2032 – 2034 CDI+0.3735% a 2% Leases (Concession) 84,214 110,214 194,428 2035 IPCA + 7.73% a 10.12% Leases (Others) 72,440 9,627 82,067 2042 9.74% a 15.24% Other 616 328 944 2035 3.00% Interest 1,033,884 - 1,033,884 - - Total denominated in local currency 4,721,151 24,788,944 29,510,095 Denominated in foreign currency: Inter-American Development Bank (IDB) 56,573 973,833 1,030,406 2023 – 2044 SOFR + 0.85% to 1.20% International Bank for Reconstruction and Development (IBRD) 33,453 1,112,127 1,145,580 2048 SOFR + 0.74% and 1.84% JICA 150,779 1,965,688 2,116,467 2029 – 2037 0.01% - 2.5% International Finance Corporation (IFC) - 3,380,431 3,380,431 2030 SOFR + 1.80% EURIBOR + 1.85% Blue Bonds - 2,828,508 2,828,508 2030 5.62% Interest 130,860 - 130,860 - - Total denominated in foreign currency 371,665 10,260,587 10,632,252 Total borrowings and financing 5,092,816 35,049,531 40,142,347 (1) TR was 0.1742% per month as of December 31, 2025; CDI stands for Interbank Deposit Rate (Certificado de Depósitos Interbancários - “CDI”), which was 14.89% per annum as of December 31, 2025; IGP-M was -1.05% per annum as of December 31, 2025; “TJLP” stands for Long-term Interest Rate (Taxa de Juros a Longo Prazo), published quarterly by the Central Bank, which was 9.07% per annum as of December 31, 2025; EURIBOR was 2.123% medium rate of 6 months for the year ended December 31, 2025; and SOFR was 4.01064% medium rate of 90 days for the year ended December 31, 2025. 76 Table of Contents The following table shows the maturity profile of our debt, as of December 31, 2025, for the period indicated: (in R$ million) 2026 2027 2028 2029 2030 After 2031 Total Borrowings and financing 5,092.8 2,259.5 1,794.5 4,172.6 7,336.5 19,486.6 40,142.3 As of December 31, 2025, R$7,056.5 million of our foreign currency denominated indebtedness, net of transaction costs, was denominated in U.S. dollars, R$1,450.5 million was denominated in Euros and R$2,125.3 million was denominated in Japanese Yen. During the year ended December 31, 2025, we entered into derivative instruments (plain vanilla swaps), with expiration dates ranging from 2030 to 2048, to fully protect us against a devaluation of the real against the U.S. dollar, the Yen, and the Euro. For more information regarding foreign currency risk and all derivatives financial instruments, see Notes 5.1(a) and 19, respectively, to our 2025 Consolidated Financial Statements included in this annual report. Our borrowings from multilateral institutions and government agencies, such as the IDB, IBRD, and JICA, are federally guaranteed, with a counter-guarantee from the State of São Paulo. For more information on the terms of these loan agreements, see “Item 7.B. Related Party Transactions—Government Guarantees of Financing.” As of December 31, 2025, our domestic debt totaled R$29,510.1 million, primarily comprising real-denominated loans from federal and state-owned banks like CEF and BNDES, alongside debentures issued between February 2018 and October 2025, and financial leasing. Financial Covenants We are subject to financial covenants under the agreements evidencing or governing our outstanding indebtedness. Indebtedness Foreign currency denominated indebtedness With respect to our indebtedness denominated in U.S. dollars, we are subject to financial covenants, including limitations on our ability to incur debt. For example: The financial covenants in our loan No. 1212 from the IDB require: • our tariff revenues must be sufficient to cover the operational expenses of our system, including administrative, operating and maintenance expenses, and depreciation; • our tariff revenues must provide a return of not less than 7% on the balance sheet value of our property, plant, and equipment, taking into account concession-related assets; and • during project execution, the balance of our short-term borrowings must not exceed 8.5% of our total equity. This loan agreement contains an early maturity clause in the event of non-compliance on our part of any obligation stipulated therein or in other contracts with the bank relating to the financing of the above-mentioned projects. We are a party to hedging agreements that cover of our debt denominated in foreign currencies. In any case, any significant devaluation of the real will affect the total portion of our debt denominated in foreign currencies when measured in reais. As a result, the net debt in reais will be affected, with consequent impact on the ratio between net debt to adjusted EBITDA, as calculated in accordance with the provisions of our loan agreements. 77 Table of Contents As of December 31, 2025, and 2024, we had met all the financial covenants of these loans and financing agreements. Local currency denominated indebtedness With respect to our outstanding indebtedness denominated in reais, we are subject to financial covenants. The financial covenants in our loans with IDB Invest and IFC require: • our debt service coverage ratio must be greater than or equal to 2.35:1.00; and • our ratio of net debt to adjusted EBITDA must be less than 3.50:1.00. The loan agreements with IDB Invest and IFC contain cross-default and cross-acceleration clauses, and early maturity clauses. The covenant clauses apply to all of our indebtedness with BNDES, which totaled R$823.8 million as of December 31, 2025. In summary, the BNDES financings specify two bands for the ratios of adjusted net debt / adjusted EBITDA, adjusted EBITDA / adjusted financial expenses, and other onerous debt / adjusted EBITDA. The financings also specify a collateral mechanism by which we assign a portion of our tariff payment receivables to BNDES in order to provide a partial guarantee of the amounts due under the financings. Under this mechanism, each month we must ensure that a portion of the tariff payments which we receive are deposited on a daily basis into a blocked collateral account, before being released to a regular movements account later in the day provided that BNDES has not notified the bank that we are in default. If the ratio of adjusted EBITDA / adjusted financial expenses is equal to or higher than 3.50, the ratio of adjusted net debt / adjusted EBITDA equal to or lower than 3.00, and the other onerous debt / adjusted EBITDA equal to or lower than 1.00, the amount that must pass through this blocked collateral account is R$361.7 million per month. If one of the three ratios mentioned above is not met in any two or more quarters, consecutive or not, within a twelve-month period, yet remain within the following band of ratios: adjusted EBITDA / adjusted financial expenses lower than 3.50 but equal to or higher than 2.80, adjusted net debt / adjusted EBITDA equal to or lower than 3.80 but higher than 3.00, and other onerous debt / adjusted EBITDA equal to or lower than 1.30 but higher than 1.00, the amount that must pass through the blocked collateral account is automatically increased by 20%. The current covenant clauses are: A. Maintenance of the following ratios, calculated quarterly and relative to amounts accumulated over the last 12 months at the time of disclosure of reviewed quarterly Consolidated Financial Statements or audited annual Consolidated Financial Statements: • adjusted EBITDA / adjusted financial expenses equal to or higher than 3.50; • adjusted net debt / adjusted EBITDA equal to or lower than 3.00; and • other onerous debt / adjusted EBITDA equal to or lower than 1.00 (where “other onerous debt” is equal to the sum of (i) social security liabilities and health care plans, (ii) installment payments of tax debt and (iii) installment payments of debt with electricity providers). B. If any one of the ratios specified in A. above is not met in any two or more quarters, consecutive or not, within a twelve-month period, we shall be deemed to be in non-compliance with the first band ratios and must, as a result, automatically increase the amount passing through the blocked collateral account by 20%, provided that the following second band ratios are met: • adjusted EBITDA / adjusted financial expenses lower than 3.50 but equal to or higher than 2.80; 78 Table of Contents • adjusted net debt / adjusted EBITDA equal to or lower than 3.80 but higher than 3.00; and • other onerous debt / adjusted EBITDA equal to or lower than 1.30 but higher than 1.00. C. If any one of the second band ratios specified in B. above is not met for any one quarter, or if we are required to but fail to ensure that the increased monthly amount specified in B. above passes through the blocked collateral account, then we shall be deemed to be in non-compliance with its ratio covenants, in which case BNDES may at its discretion: • require us to provide additional financial guarantees within a deadline specified by BNDES, which may not be less than 30 days; • suspend the release of funds; and/or • declare the financings to be immediately due and payable. Additionally, since 2018, we are subject to financial covenants under the new financing agreements executed with CEF. These financial covenants require us to maintain the following financial indexes, calculated for the past 12 months on a quarterly basis: • adjusted EBITDA / adjusted financial expenses, equal to or greater than 2.80; • adjusted net debt / adjusted EBITDA, equal to or lower than 3.80; • other onerous debt / adjusted EBITDA equal to or lower than 1.30. These agreements provide that disbursements may be suspended if any of these covenants are not being complied with. In the event of non-compliance with the terms of these agreements, CEF may request the anticipated payment of the entire loan. The agreements with CEF also contain a cross-default clause and an early maturity clause. In the event of non-compliance with the terms of the contract, the CEF can request the anticipated payment of part or all of the loan. See Note 17 to our 2025 Consolidated Financial Statements included in this annual report. The table below shows the more restrictive covenants ratios and our financial covenants ratios as of December 31, 2025. The twenty-second, twenty-third, twenty-fourth, twenty-sixth, twenty-seventh, twenty-eighth, twenty-ninth, thirtieth, thirty-first, 32nd and 33rd debenture issuances require us to maintain an adjusted EBITDA/paid financial expenses ratio equal to or higher than 1.5:1.0 and an adjusted net debt/adjusted EBITDA ratio equal to or lower than 3.50:1.0. These issuances have a cross-acceleration clause. Restrictive Ratios Adjusted EBITDA / adjusted financial expenses Equal to or higher than 2.80:1.00 EBITDA/paid financial expenses Equal to or higher than 2.35:1.00 Adjusted net debt / adjusted EBITDA Equal to or lower than 3.80:1.00 Net debt/adjusted EBITDA Equal to or lower than 3.50:1.0 Other onerous debt(1)/ adjusted EBITDA Equal to or lower than 1.30:1.00 (1) “other onerous debt” corresponds to the sum of social security liabilities, health care plan, installment payment of tax debts and installment payment of debts with the electricity supplier. As of December 31, 2025 and 2024, we complied with all the covenants of our loans and financing agreements. 79 Table of Contents Recent Developments Offering and Sale of Debentures On February 10, 2026, we completed our 38th issuance of simple, non-convertible, unsecured debentures, with an aggregate principal amount of R$6,292.1 million, in five series, including: (i) a first series with an aggregate principal amount of R$1,635.7 million, bearing interest at 6.2907% p.a., maturing in February 2036; (ii) a second series with an aggregate principal amount of R$1,364.7 million, bearing interest at 6.3507% p.a., maturing in February 2038; (iii) a third series with an aggregate principal amount of R$1,291.7 million, bearing interest at 6.2467% p.a., maturing in February 2041; (iv) a fourth series with an aggregate principal amount of R$1,000.0 million, bearing interest at CDI index plus a spread of 0.64% p.a.; and (v) a fifth series with an aggregate principal amount of R$1,000.0 million, bearing interest at CDI index plus a spread of 0.72% p.a. These debentures were offered and sold in Brazil exclusively to professional investors (investidores profissionais), as defined under applicable CVM regulations. US$1,500 Million Loan Agreement and US$1,350 Million Blue Bond Issuance On January 26, 2026, we entered into a loan agreement with the Inter-American Investment Corporation, consisting of (i) a senior unsecured loan in an aggregate principal amount of US$150.0 million, issued in a single tranche and maturing in 2038 (the “Term Loan A”), and (ii) a blue unsecured loan in an aggregate principal amount of US$1,350.0 million, issued in two tranches maturing in 2031 and 2036, respectively (the “Term Loan B” and, together with the Term Loan A, the “Loans”). The Term Loan B serves as the underlying asset for the issuance of two series of blue senior secured notes by Nova Securitisation S.À.R.L, including a US$850.0 million in aggregate principal amount of 5.750% blue senior secured notes due 2031, and a US$500.0 million in aggregate principal amount of 6.500% blue senior secured notes due 2036 (“Blue Bonds”). The Blue Bonds are listed on the Euro MTF Market of the Luxembourg Stock Exchange. The Blue Bonds were offered solely to qualified institutional buyers in the United States under Rule 144A and to eligible purchasers in other jurisdictions (excluding Brazil and the U.S.) under Regulation S of the U.S. Securities Act of 1933, as amended. The offering and sale of the Blue Bond were completed on February 3, 2026. We intend to use the net proceeds from the Loans and the Blue Bonds for projects supporting our universalization targets for basic sanitation in the Brazilian state of São Paulo, including construction and upgrading of sewage treatment facilities and expansion of collection systems. Capital Requirements We have, and expect to continue having, substantial liquidity and capital resource requirements. These requirements include debt-service obligations, capital expenditures to maintain, improve and expand our water and sewage systems, and dividend payments and other distributions to our shareholders, including the State of São Paulo. Capital Expenditures Historically, we have funded and plan to continue funding our capital expenditures with funds generated by operations and with long-term financing from international and national multilateral agencies and development banks. We generally include in our capital expenditure program for the following year the amount of investment that was not realized in the previous year. For the year ended December 31, 2025, we recorded R$15.2 billion to improve and expand our water and sewage system and to protect our water sources in order to meet the growing demand for water and sewage services in the State of São Paulo. We have budgeted investments in the amount of approximately R$70 billion from 2024 through 2029. For more information, see “Item 4.A. History and Development of the Company—Main Focus of our Capital Expenditure Program.” 80 Table of Contents Dividend Distributions We are required by our bylaws to make dividend distributions, which can be made as payments of interest on shareholders’ equity in an amount equal to or greater than 25% of the amounts available for distribution. In addition, our dividend policy, which was approved at the annual shareholders’ meeting held on July 22, 2024, establishes that this percentage was maintained until 2025. After 2025, it may be increased to 100% in 2030, provided we reach the Universalization Targets. We declared dividends of R$2,381.6 million, R$2,549.8 million and R$984.5 million in the years ended December 31, 2025, 2024 and 2023, respectively. The Basic Sanitation Law prohibits the distribution of profits and dividends from the Concessionaire that fails to comply with the targets and schedules set out in the respective Contracts. For more information, see “Item 3.D. Risks Relating to Our Common Shares and ADSs—We may not always be in a position to pay dividends or interest on shareholders’ equity and ADSs.” Judicial payment orders (precatório) As of December 31, 2025, we have judicial payment orders issued in our favor in the inflation adjusted amount of R$ 814.3 million, which are not recognized in our 2025 Consolidated Financial Statements because of the difficulty to obtain a reasonable estimate to measure such assets, due to the uncertainties related to the beginning and the end of the payments. Judicial payment orders are recognized upon the beginning of their receipt or when they are traded. For more information on judicial payment orders, see Note 10 to our 2025 Consolidated Financial Statements included in this annual report. Year Ended December 31, 2024 Compared to Year Ended December 31, 2023 For a discussion of our liquidity and capital resources for the year ended December 31, 2024 compared to the year ended December 31, 2023, see “Item 5. Operating and Financial Review and Prospects — B. Liquidity and Capital Resources” of our annual report on Form 20-F for the year ended December 31, 2024, filed with the SEC on April 30, 2025. Off-Balance Sheet Arrangements We had no off-balance sheet arrangements as of December 31, 2025, except for the unrecorded contractual commitments described in the table below. Tabular Disclosure of Contractual Obligations 81 Table of Contents Our debt obligations and other contractual obligations as of December 31, 2025 were: Less than 1 year 1-3 years 3-5 years More than 5 years Total (in millions of reais) Borrowings and financing 5,092.8 4,053.9 11,509.0 19,486.6 40,142.3 Interest on borrowings and financing(1) 3,497.1 7,363.3 6,334.3 7,613.3 24,808.0 Trade payables and contractors 2,400.0 - - - 2,400.0 Services payable 2,772.4 - - - 2,772.4 Public-Private Partnership - PPP 239.1 478.1 478.1 2,130.4 3,325.7 Interest Public-Private Partnership - PPP 230.6 514.9 590.6 3,311.8 4,647.9 Contractual obligations(2) 19,289.4 12,201.4 3,441.4 4,101.3 39,033.4 Total 33,521.4 24,611.6 22,353.4 36,643.4 117,129.7 (1) Estimated interest payments on loans and financing were determined considering the interest rates as of December 31, 2025. However, our loans and financing are subject to variable interest indexation and foreign exchange fluctuations, and these estimated interest payments may differ significantly from payments actually made. The debt agreements have cross-default clauses. (2) The unrecorded contractual commitments are the future obligations of investments and expenses as set out in Note 34 to our 2025 Consolidated Financial Statements. We believe that we can meet the maturity schedule through a combination of funds generated by operations, the net proceeds of new issuances of debt securities in the Brazilian and international capital markets and additional borrowings from domestic and foreign lenders. Our borrowings are not affected by seasonality. For information concerning the interest rates on our indebtedness outstanding as of December 31, 2025, see Note 17 to our 2025 Consolidated Financial Statements, included elsewhere in this annual report. C. Research and Development, Patents and Licenses, Etc. Research and innovation The advancement of research and technological development is part of our strategic guidelines, and aims to implement innovation in operations, processes and services. Such efforts seek to increase organizational efficiency, reflecting in greater customer satisfaction, improved quality of life, environmental sustainability and competitiveness, with improved productivity and quality of our processes and services. Our strategic innovation process involves the creation of new business models, new ways of meeting the needs of consumers, new organizational processes, new ways of competing and cooperating in the business environment and improvements to service delivery, while at the same time promoting protection of the environment and public health. We won the Valor Inovação Brasil 2024 award, winning first place in the “Infrastructure” segment, which also incorporates the sanitation sector. The award is promoted by the newspaper Valor Econômico and Strategy&, which is PwC’s strategic consultancy. The award evaluates the innovative renewal of organizations in four major blocks: planning, execution, results and recognition. Our third place in 2022, second place in 2023 and first place in 2024, shows our role in innovation in the sanitation sector. In addition, considering the general ranking of the 150 most innovative companies in Brazil in all 25 mapped segments, we were ranked 11th in the same award. 82 Table of Contents We set up a Corporate “Research, Technological Development and Innovation” Program, which allows us to differentiate the financial resources spent specifically for this purpose within our budget structure. For the year ended December 31, 2025, we allocated R$76.8 million to Research, Development and Innovation (“RD&I”) projects solely through the corporate innovation area. These resources are a differential in our results and indicate our capacity for innovation and pioneering, which can bring fiscal, tariff and financial advantages. We carry out several actions for the implementation of innovative technological solutions systematically throughout our company. These solutions are aimed at improving construction and operational processes for water and wastewater systems, water and wastewater treatment solutions, asset control and management, renewable energy generation processes, energy efficiency, user relationship technologies, circular economy projects, waste reduction or reuse methods, among others. Some may even represent new business opportunities. In addition, we have submitted several innovation projects to the Brazilian Ministry of Science and Technology, requesting tax benefits provided for in certain Brazilian laws such as the “Lei do Bem” (Federal Law nº 11.196/2005). For the 2023 calendar year, 100% of our claims for RD&I expenditures were approved by that Ministry, totaling approximately R$66.2 million, which represents a tax credit of more than R$18.0 million for the company. Currently under review are our reimbursement requests for the 2024 calendar year, submitted in September 2025, totaling approximately R$79.4 million in R&D expenses, which, if totally approved, will represent a tax credit of over R$21.6 million, expanding the mechanisms for financial incentives for innovation. In addition, based on programs already in place in the power and gas sectors, we maintain a portfolio of prioritized projects with ARSESP (regulatory agency) in its Quadrennial Research and Technological Development Program for Innovation in Basic Sanitation Services (PD&I Program), which requires the application of the 0.05% of revenue to RD&I projects. Accordingly, the first cycle of the program, covering the tariff cycle 2021-2025, is in its final phase of completion. ARSESP has extended this first cycle of the program to include 2025. The total financial amount approved in the PD&I Program has surpassed R$41.0 million, to be applied in 14 projects approved by ARSESP to be carried out by the end of the cycle, in order to meet the goal of the current cycle, of which approximately R$14.8 million were executed in 2025.In line with business planning, the structuring of RD&I actions is based on the concept of a circular economy; that is, focused on the intelligence of nature, the circular process opposes the traditional linear production process. As part of this concept, residues are inputs to produce new products and new cycles. We have highlighted below certain RD&I projects that use the concept of a circular economy, which strongly supports resource recovery, as part of the processes for the water and sewage treatment. The sequential implementation of integrated actions for liquid, solid and gaseous sewage treatment phases at the sewage treatment plant in the municipality of Franca aims to optimize processes and transform the site into a resource recovery plant. Since 2018, a biogas upgrade project in this sewage treatment plant has been producing biomethane for vehicle use. This sewage treatment plant treats an average of 500 liters per second of sewage and produces around 2,500 m³ of biogas per day. The upgrade system can produce biomethane to replace 1,500 liters of common gas daily. The biomethane currently supplies part of our Franca fleet. As a result of the tests carried out, we are studying the replication of the technology in other large-scale sewage treatment plants located in the São Paulo metropolitan region and in the countryside of the State of São Paulo. In the same plant, we developed and are operating a sludge dryer based on solar radiation. The project also provides for other actions under development , such as the use of energy from hydraulic sources, as well as other beneficial applications of biogas such as the thermal sludge drying system currently being implemented. At the Barueri city sewage treatment plant, we implemented a plasma gasification system for the processing of sludge generated. At the end of the process, this system generates inert vitreous residue with a drastic reduction in its volume, with a potential for reuse as raw material in construction, meaning it does not need to be disposed of in landfills. In 2024, we concluded the installation of a pilot thermal sludge treatment plant using pyrolysis. In 2025, we performed operational tests to evaluate the potential of byproducts generated, such as biocarbon, pyrolytic oil and synthesis gas. In another ongoing project, results of the studies conducted under the Support Program for Research in Partnership for Technological Innovation (PITE-SABESP/FAPESP) in collaboration with UNESP and EMBRAPA were presented. These studies focused on transforming sludge waste from Water Treatment Plants into raw materials for civil engineering and agriculture, adding value to this byproduct. 83 Table of Contents As a component of our partnership with FAPESP, financial resources are invested equally to subsidize and support the development of basic and applied research projects under the Support Program for Research in Partnership for Technological Innovation for research projects in academic or research institutions, whose themes originated from the demands pointed out by the operational areas. This partnership has already resulted in 19 projects with different universities, such as: USP, Technological Institute of Aeronautics, UNIFESP, National Institute for Space Research and UNESP. The partnership provides for a non-refundable financing of R$50.0 million, divided equally between us and FAPESP. Projects from the first and second collaborative calls led to the filing of seven national patent applications before the INPI, three of which were granted, and also two international patent applications under the PCT system before the World Intellectual Property Organization, of which one was granted, and two software registration requests. The 12 projects selected in the third call for proposal, two have already been completed and another ten are currently in the development phase. Another innovative project that we have implemented is the Pinheiros River Oxygenation System. This project is being developed alongside other sanitation programs in Rio Pinheiros. The project consists of the implementation of an innovative oxygenation technology called SDOx. This technology, unlike conventional aeration technologies, has the potential to transfer a greater amount of oxygen to the water, through a supersaturated solution and its dispersion in the water. The goal of this project is to enhance the natural self-purification process by artificially increasing the oxygen levels in the water and to verify the technical-economic feasibility of the technology, with a view to replicating it. The project is in its fourth year of operation, with satisfactory results in terms of the gradual increase in oxygen concentration in the upper channel of the river. With the water quality data obtained with the project, a study is carried out by CETESB to assess the improvement in air quality around the Pinheiros River has shown a connection between the improvement in air quality and the improvement in the river’s water quality, as a result of the sanitation actions implemented in the Pinheiros River basin. Furthermore, in 2025 an innovative technology called water passive intake was implemented, consisting of a filter with flow control and backwashing with compressed air. This improvement aims to prevent shutdown events that were caused by the large amount of debris contained in the river water. A new department was created in 2024 with the purpose of expanding operations to rural areas and informal urban settlements. In 2025 this department structured guidelines and a portfolio of unconventional solutions to meet the targets set in the new concession agreement, moving towards universal access. Open Innovation We invest in the development and implementation of initiatives as part of our open innovation concept, a concept embedded in our actions. This concept generates ideas, thoughts, processes, prospect for solutions, shares needs, and exchanges knowledge and research with the participation of internal and external segments of our company. These contributions span a diverse range of sectors, enabling us to harness innovative solutions and technologies to enhance our processes, products and services. With this, we seek innovative solutions from the productive sectors of the market, including startups, for the development of solutions. Specifically, we encourage startups to take on challenges and propose validated solutions for a wide array of problems. Their goal is to achieve scalability and acceleration, ultimately creating a positive impact on their new products and businesses. This proactive approach aims to stimulate the sanitation market and potentially lead to the development of solutions that cater to our specific needs. We also perform tests on innovative solutions that arise in response to market demands, at various stages of development, to evaluate their suitability for application within our operations. These collaborative technological initiatives not only enable us to propose technology-driven enhancements to our processes and services but also afford external companies in the market an opportunity to rigorously trial their solutions in real sanitation environments. This provides a platform for assessing the effectiveness of their solutions and, when necessary, identifying areas for improvement. 84 Table of Contents A new internal innovation platform is under development, with the goal of capturing and developing innovative ideas and projects in a simplified, participatory way, open to all company employees. Through this open innovation program, we are laying the groundwork for an innovative ecosystem within the sanitation sector. New actions implemented by SABESP in 2025 to accelerate its initiatives to encourage and promote innovation: 1) Contracting specialized innovation services through the signing of two contracts focused on the Execution of Specialized Innovation Services, encompassing the implementation of 50 open innovation initiatives or the development of prototypes of solutions based on artificial intelligence. It also includes conducting SABESP's Innovation Diagnosis and promoting structured engagement actions, such as hackathons, bootcamps, and talk series, fostering a culture of innovation among employees and partners. 2) Implementation of the SABESP Innovation Hub: This space was implemented in the São José dos Campos, Parque de Inovação Tecnológica “PIT” (Technological Innovation Park), a strategic environment dedicated to the development of innovative technologies focused on the universalization of sanitation, operational efficiency, and continuous process improvement. We also publish the DAE Magazine a continuous-flow engineering journal produced by a dedicated team of opinion leaders that had released over 250 editions since its inaugural edition. This journal was ranked as “B1” category publication in the Qualis/CAPES system. Through the dissemination of technical and scientific articles covering topics related to basic and environmental sanitation, DAE Magazine’s objective is to foster and propagate advancements in processes, innovations and technological breakthroughs. D. Trend Information We expect to continue operating in a competitive and regulated environment, which may place pressure on our profitability and on the performance of our assets. The following list sets out what we believe to be the most important trends, uncertainties, and events that are reasonably likely to continue to have a material effect on our revenues, income from continuing operations, profitability, liquidity, and capital resources, or that may cause reported financial information to be not necessarily indicative of future operating results or financial condition: • Following the consummation of our privatization in July 2024, investment levels and capital expenditure activities increased significantly throughout 2024 and 2025, primarily in connection with the advancement of universalization targets under the Concession Agreement for URAE-1. We invested approximately R$10.6 billion in the period following privatization, with a substantial acceleration in 2025, including approximately R$6.5 billion invested in the first half of 2025 alone. These investments support the advancement of the universalization targets, which we expect to meet by 2029, but also create exposure to uncertainties such as pressure on supply chains, higher construction costs, and the need to operate in areas with complex engineering challenges, including informal settlements and rural zones. These factors may materially affect our cost structure, timelines, and capital requirements. For further information, see “Item 3.D. Risk Factors — Risks Relating to the Regulatory Environment — We are exposed to risks associated with the Concession Agreement for URAE-1, which may materially impact our financial condition and operating results.” • The New Legal Framework continues to introduce significant regulatory requirements, including stricter oversight, progressive universalization metrics, and potential tariff implications. ANA’s Reference Standard No. 08/2024, which became effective in May 2024, establishes clearer responsibilities for service providers, mandates quality standards, and reinforces the need for progressive expansion of service coverage. While these regulations aim to harmonize rules nationwide, they also create uncertainties regarding compliance costs, competitive dynamics, and the potential need to seek the restoration of economic and financial equilibrium under our concession agreements, particularly as municipalities formalize regionalized service structures under the New Legal Framework for Basic Sanitation. • Our operations remain exposed to droughts, storms, and other extreme weather conditions that may disrupt production, energy supply, and service continuity. In 2025, we experienced one of the driest periods in the Southeast region of Brazil in the past decade, adversely affecting the storage levels of our water sources. More broadly, torrential rainfall events and severe storms have increasingly caused interruptions due to impacts on energy distribution infrastructure, reducing production capacity and increasing operational risk. 85 Table of Contents These risks may adversely affect water availability for abstraction, treatment, and distribution, and may have a material adverse effect on our financial condition and results of operations. For more information, see “Item 3.D. Risk Factors — Risks Relating to Environmental Matters and Physical and Climate Transition Risks — Extreme weather conditions and climate change may have a material adverse impact on our business, financial condition or results of operations” and “Item 3.D. Risk Factors — Risks Relating to Environmental Matters and Physical and Climate Transition Risks — Droughts, such as the 2014 – 2015 water crisis, can cause a material impact on consumption habits and, consequently, on our business, financial condition or results of operations.” In addition to the information set out above, see “Cautionary Statements About Forward-Looking Statements” for further information related to our forward-looking statements, and “Item 3.D. Risk Factors” for a description of certain factors that could affect our industry and our own performance in the future. E. Critical Accounting Estimates The disclosures related to judgements and estimates can be found in Note 6 to our 2025 Consolidated Financial Statements, which are included elsewhere in this annual report.