Investing in our securities involves a high degree of risk. You should carefully consider the following information about the risks described below, together with the other information contained in this report and in our other public filings in evaluating our business. If any of the following risks actually occur, our business could be materially harmed, and our financial condition and results of operations could be materially and adversely affected. As a result, the trading price of our securities could decline, and you might lose all or part of your investment. We have marked with an asterisk those risk factors that reflect substantive changes from the risk factors included in our Annual Report on Form 10-K for the year ended December 31, 2025. Summary of Risk Factors There are a number of risks related to our business and our securities. Some of the principal risks related to our business include the following: ● Our ability to generate substantial revenue from the sale of our medicines; ● The availability of adequate coverage and payment rates for our medicines; ● Our and our partners’ ability to compete effectively; ● Our ability to successfully manufacture our medicines; ● Our ability to successfully develop and obtain marketing approvals for our medicines; ● Our ability to secure and maintain effective corporate partnerships; ● Our ability to sustain cash flows and achieve consistent profitability; ● Our ability to protect our intellectual property; ● Our ability to maintain the effectiveness of our personnel; ● The impacts of health epidemics, climate change, war and other events; ● Our dependence upon our own and third-party data, information technology systems and infrastructure; and ● The other factors set forth below. Risks Related to the Commercialization of our Medicines We have limited experience as a company in commercializing medicines and we will have to continue to invest significant resources to develop our capabilities. If we are unable to establish or maintain an effective commercialization infrastructure, or enter into agreements with third parties to commercialize our medicines, we may not be able to successfully commercialize our medicines. We have historically relied on third parties to commercialize our marketed medicines and have limited experience as a company in commercializing medicines. We currently have two independently launched medicines, TRYNGOLZA and DAWNZERA, and we expect to independently launch additional medicines in the near future. Any failure to effectively commercialize our medicines, including our failure to allocate resources to our commercial launches efficiently or timely, could adversely impact the revenue we generate from our medicines. If the commercialization of our independently launched medicines and future sales of such are less successful than anticipated by us or our investors or securities analysts, our stock price could decline and our business may be harmed. 39 Table of Contents We will have to continue to invest significant financial and management resources to build and maintain the infrastructure required to successfully commercialize our medicines. We will need to establish and maintain effective sales teams for each of our independently launched medicines and there are significant risks involved in managing a sales organization, including our ability to hire, retain and incentivize qualified individuals, generate sufficient sales leads, provide adequate training to sales and marketing personnel, and effectively manage a geographically dispersed sales and marketing team. We must also continue to scale-up existing internal support functions to aid our commercialization efforts, which will need to work effectively in coordination with new commercial functional areas. Any failure to establish or maintain an effective commercialization infrastructure, including our sales, marketing, market access, distribution, and related capabilities, scale-up our existing support functions, or effectively integrate new functional areas, could adversely affect our ability to successfully commercialize our medicines. If we choose to rely on third parties to assist us in commercializing our medicines, we may not be able to enter into collaborations or hire consultants or external service providers on acceptable financial terms, or at all. In addition, if we continue to engage third parties to assist us in the commercialization of our medicines, our product revenues and profitability may be lower than if we commercialized such medicines ourselves. The proximity of our current and planned independent launches could increase the likelihood that the risks set forth above will occur. If the market does not adopt our medicines, including our commercial medicines and our medicines in development, we are not likely to generate substantial revenues or become consistently profitable. Even if our medicines are authorized for marketing, our success will depend upon the medical community, patients and third-party payers considering our medicines medically useful, cost-effective, safe and convenient. Even when the FDA or foreign regulatory authorities authorize our or our partners’ medicines for commercialization, doctors may not prescribe our medicines to treat patients. Furthermore, we and our partners may not successfully commercialize additional medicines. Additionally, in many of the markets where we or our partners may sell our medicines in the future, if we or our partners cannot agree with the government or other third-party payers regarding the price we can charge for our medicines, we may not be able to sell our medicines in that market. Similarly, cost control initiatives by governments or third-party payers could decrease the price received for our medicines or increase patient coinsurance to a level that makes our medicines, including our commercial medicines and our medicines in development, economically unviable. If the pricing of any of our medicines decreases for any reason, it will reduce our revenue for such medicine. For example, Biogen has in the past disclosed that SPINRAZA revenue decreased in part due to lower pricing in the U.S. and certain rest-of-world markets. The degree of market adoption of our medicines, including our commercial medicines and our medicines in development, depends upon several factors, including the: ● receipt and scope of marketing authorizations; ● establishment and demonstration in the medical and patient community of the efficacy and safety of our medicines, public perception regarding our medicines and their potential advantages over competing products; ● cost and effectiveness of our medicines compared to other available therapies; ● patient convenience of the dosing regimen for our medicines; and ● reimbursement policies of government and third-party payers. Based on the profile of our medicines, physicians, patients, patient advocates, payers or the medical community in general may not adopt any of the medicines that we or our partners may develop. For example, the product label for WAYLIVRA in the EU requires regular blood monitoring, which has negatively affected our ability to attract and retain patients for this medicine. 40 Table of Contents If government or other third-party payers fail to provide adequate coverage and payment rates for our medicines, including our commercial medicines and our medicines in development, or if healthcare reform measures increase our costs, decrease our sales, or negatively impact reimbursement for our products, our revenue will be limited. In both domestic and foreign markets, sales of our current and future products will depend in part upon the availability of coverage and reimbursement from third-party payers. The majority of patients in the U.S. who would fit within our target patient populations for our medicines have their healthcare supported by a combination of Medicare coverage, other government health programs such as Medicaid, managed care providers, private health insurers and other organizations. Coverage decisions may depend upon clinical and economic standards that disfavor new medicines when more established or lower cost therapeutic alternatives are already available or subsequently become available. Assuming coverage is approved, the resulting reimbursement payment rates might not be enough to make our medicines affordable. Even if favorable coverage status and adequate reimbursement rates are attained, less favorable coverage policies and reimbursement rates may be implemented in the future. Accordingly, our commercial medicines and our medicines in development will face competition from other therapies and medicines for limited financial resources. Furthermore, we or our partners may need to conduct post-marketing studies to demonstrate the cost-effectiveness of any future products to satisfy third-party payers. These studies might require us to commit a significant amount of management time and financial and other resources. In addition, third-party payers may never consider our future products as cost-effective and adequate third-party coverage and reimbursement might not be available to enable us to maintain price levels sufficient to realize an appropriate return on investment in product development. Third-party payers, whether foreign or domestic, or governmental or commercial, are developing increasingly sophisticated methods of controlling healthcare costs. In addition, in the U.S., no uniform policy of coverage and reimbursement for medicines exists among third-party payers. Therefore, coverage and reimbursement for medicines can differ significantly from payer to payer. Further, we believe that future coverage, reimbursement and pricing will likely be subject to increased restrictions both in the U.S. and in international markets. In the U.S., recent health reform measures have resulted in reductions in Medicare and other healthcare funding, and there have been several recent U.S. Congressional inquiries, legislation and executive orders designed to, among other things, reduce drug prices, increase competition (including by enhancing support for generic and biosimilar drugs), lower out-of-pocket drug costs for patients, curtail spread pricing practices by pharmacy benefit managers, and foster scientific innovation to promote better health care and improved health. For example, the Affordable Care Act substantially changed the way healthcare is financed by both governmental and private insurers and continues to significantly impact the U.S. pharmaceutical industry. Since its enactment, there have been amendments and judicial, Congressional and executive branch challenges to certain aspects of the Affordable Care Act, as well as efforts to repeal or replace certain aspects of the Affordable Care Act. We expect that additional U.S. federal healthcare reform measures will be adopted in the future, any of which could limit the amounts that the U.S. federal government will pay for healthcare products and services, which could result in reduced demand or revenue for our commercial medicines and our medicines in development. In addition, the Inflation Reduction Act of 2022, or the IRA, includes key actions aimed at reducing the costs of prescription drugs and allows the U.S. Department of Health and Human Services, or HHS, to negotiate the price of certain single-source drugs covered under Medicare and establish a price cap on such drugs. The IRA, among other things, (1) directed HHS to negotiate the price of certain single-source drugs and biologics that have been on the market for at least seven years covered under Medicare, or the Medicare Drug Price Negotiation Program, and (2) imposed rebates under Medicare Part B and Medicare Part D to penalize price increases that outpace inflation. Each year, up to 20 products will be selected by HHS for the Medicare Drug Price Negotiation Program. Products subject to the Medicare Drug Price Negotiation Program are expected to experience a significant reduction in reimbursement from the Medicare program on a per unit basis. The current U.S. Presidential administration is pursuing policies to reduce regulations and expenditures across government agencies, including at the FDA, HHS, Centers for Medicare & Medicaid Services, or CMS, and other related agencies, with a particular focus on most favored nation pricing equal to or lower than those paid in other developed nations. These actions, presently directed by executive orders or memoranda from the Office of Management and Budget, may propose additional policy changes that create uncertainty for our business. For example, in furtherance of the administration’s drug pricing initiatives, in late 2025, CMS issued proposed rules that, if finalized, would implement new mandatory and voluntary payment models to implement a most favored nation rebate model. These models are referred to as the GLOBE Model, GUARD Model and GENEROUS Model. At this time, it remains unclear whether the proposed models will be finalized and, if so, whether any changes will be made prior to their implementation. These and other recent actions and policies may significantly reduce U.S. drug prices, potentially impacting manufacturers’ global pricing strategies and profitability, while increasing their operational costs and compliance risks. 41 Table of Contents Any reduction in reimbursement from Medicare and other government programs may result in a similar reduction in payments from private payers. Our future product sales may be subject to additional discounts from list price in the form of rebates and discounts provided to covered entities under the Public Health Service Act 340B drug pricing program. Changes to the 340B program or to Medicare or Medicaid programs at the federal or state level, including outcomes of ongoing litigation in our industry, may impact our product prices and rebate liability. At the state level, legislatures have increasingly passed legislation and implemented regulations designed to control pharmaceutical and biological product pricing, including price or patient reimbursement constraints, discounts, restrictions on certain product access and marketing cost disclosure and transparency measures, and, in some cases, designed to encourage importation from other countries and bulk purchasing. Third-party coverage and reimbursement for medicines may not be available or adequate in either the U.S. or international markets, which would negatively affect the potential commercial success of our products, our revenue and our profits. If we or our partners fail to compete effectively, our medicines, including our commercial medicines and our medicines in development, will not generate significant revenues.* The biotechnology and pharmaceutical industries are highly competitive and subject to significant and rapid technological change. Our competitors engage in drug discovery throughout the world, are numerous, and include, among others, major pharmaceutical companies and specialized biopharmaceutical firms. In addition, other companies are engaged in developing RNA-targeted technology. Our competitors may, among other things, relative to our medicines or medicines in development: ● develop safer or more effective products; ● develop less costly products; ● receive more favorable reimbursement coverage; ● implement more effective approaches to sales and marketing; ● develop products that are more convenient to use than our medicines; ● have access to increased manufacturing capacity; ● obtain regulatory approval for products more quickly; or ● establish superior intellectual property positions. These competitive advantages could make our medicines, including our commercial medicines and our medicines in development, obsolete or non-competitive. Many of our competitors have substantially greater financial, technical and human resources than we do. In addition, many of these competitors have significantly greater experience than we do in conducting preclinical testing and human clinical studies of new pharmaceutical products, in obtaining FDA and other regulatory authorizations of such products and in commercializing such products. There are several pharmaceutical and biotechnology companies engaged in the development or commercialization in certain geographic markets of products against targets that are also targets of products in our development pipeline or of medicines we are commercializing. For example: ● TRYNGOLZA faces competition in FCS from a commercial competitor and, in sHTG, could face competition from commercial competitors in the future; ● DAWNZERA faces competition from several commercial competitors, including an oral product, and could face competition from additional commercial competitors in the future; ● WAINUA faces competition from numerous competitors, including an oral product in markets outside the U.S.; ● SPINRAZA faces competition from both a gene therapy product and an oral product for the treatment of SMA. Biogen has in the past disclosed that SPINRAZA revenue decreased due to a reduction in demand as a result of increased competition and that future sales of SPINRAZA may be adversely affected by competing products; ● QALSODY could face competition from a commercial competitor in the future; and ● Obudanersen, if approved, could face competition from commercial competitors in the future, including oral products. For details regarding medicines that compete or may compete directly with our marketed medicines and late-stage medicines, refer to the section titled, Competition, in Part I, Item 1, Business, in our Annual Report on Form 10-K for the year ended December 31, 2025. 42 Table of Contents Certain of our partners are pursuing other technologies or developing other medicines either on their own or in collaboration with others, including our competitors, to treat some of the same diseases that our own programs target. Competition may negatively impact a partner’s focus on and commitment to our medicines and, as a result, could delay or otherwise negatively affect the commercialization of our partnered medicines. Additionally, companies that are developing medicines that target the same patient populations as our medicines in development may compete with us to enroll participants in the clinical trials for such medicines, which could make it more difficult for us to complete enrollment for these clinical trials. Our medicines could be subject to regulatory limitations following approval. Following approval of a medicine, we and our partners must comply with comprehensive government regulations regarding the manufacture, marketing and distribution of medicines. The FDA and foreign regulatory bodies have the authority to impose significant restrictions on an approved medicine through the product label. We or our partners may not obtain the labeling claims necessary or desirable to successfully commercialize our medicines, including our commercial medicines and our medicines in development. Promotional communications regarding prescription medicines must be consistent with the information in the product’s approved labeling. Additionally, prescription medicines may be promoted only for the approved indication(s) in accordance with the approved label. The FDA and other regulatory authorities actively enforce the laws and regulations prohibiting the promotion of off-label uses, and a company that is found to have improperly promoted off-label uses may be subject to significant liability. In addition, when approved, the FDA or a foreign regulatory authority may condition approval on the performance of post-approval clinical studies or patient monitoring, which could be time-consuming and expensive. For example, in connection with the conditional marketing approval for WAYLIVRA in the EU, we are required to conduct a post-authorization safety study to evaluate the safety of WAYLIVRA on thrombocytopenia and bleeding in FCS patients taking WAYLIVRA. If the results of such post-marketing studies are not satisfactory, the FDA, EC or foreign regulatory authorities may withdraw the marketing authorization or may condition continued marketing on commitments from us or our partners that may be expensive and time-consuming to fulfill. If we or others identify side effects after any of our medicines are on the market, or if manufacturing problems occur subsequent to regulatory approval, or if we, our contract manufacturing organizations, or our partners fail to comply with regulatory requirements, we or our partners may, among other things, lose regulatory approval and be forced to withdraw products from the market, need to conduct additional clinical studies, incur restrictions on the marketing, distribution or manufacturing of the product, and/or change the labeling of our medicines. We depend on our collaborations with Biogen for the development and commercialization of SPINRAZA and QALSODY. We have entered into separate collaborative arrangements with Biogen to develop and commercialize SPINRAZA and QALSODY. We entered into these collaborations primarily to: ● fund our development activities for SPINRAZA and QALSODY; ● seek and obtain regulatory approvals for SPINRAZA and QALSODY; and ● successfully commercialize SPINRAZA and QALSODY. We are relying on Biogen to obtain additional regulatory approvals for SPINRAZA and QALSODY, generate additional clinical data for SPINRAZA and QALSODY, manufacture SPINRAZA and QALSODY, and successfully commercialize SPINRAZA and QALSODY. In general, we cannot control the amount and timing of resources that Biogen devotes to our collaborations. If Biogen fails to further develop SPINRAZA or QALSODY, obtain additional regulatory approvals for SPINRAZA or QALSODY, manufacture SPINRAZA or QALSODY, or successfully commercialize SPINRAZA or QALSODY, revenues for SPINRAZA or QALSODY would be negatively affected. In addition, our collaborations with Biogen may not continue for various reasons. Biogen can terminate our collaborations at any time. If Biogen stops developing or commercializing SPINRAZA or QALSODY, we would have to seek or spend additional funding, and SPINRAZA’s or QALSODY’s commercialization may be harmed. 43 Table of Contents We depend on our collaboration with AstraZeneca for the development and commercialization of WAINUA.* In December 2021, we entered into a collaborative agreement with AstraZeneca under which we granted AstraZeneca exclusive worldwide rights to develop and commercialize WAINUA, with the parties sharing responsibility and costs for development and U.S. commercialization activities, and AstraZeneca assuming sole responsibility for commercialization outside the U.S. We exercised our opt-out right under the agreement and the opt-out process set forth in the agreement is underway. In general, we cannot control the amount and timing of resources that AstraZeneca devotes to our collaboration. In addition, we do not have control over whether AstraZeneca elects to terminate the collaborative arrangement. If AstraZeneca fails to further develop or successfully commercialize WAINUA for any reason, our revenues for WAINUA would be negatively affected. If we are not successful in expanding our manufacturing capabilities or cannot manufacture our medicines or contract with a third party to manufacture our medicines at costs that allow us to charge competitive prices to buyers, we cannot market our products profitably.* To successfully commercialize any of our medicines, we need to optimize and manage large-scale commercial manufacturing capabilities either on a standalone basis or through a third-party manufacturer. As our drug development and commercial pipeline increases and matures, we will have a greater need for clinical trial and commercial manufacturing capacity. We also must ensure that we have the manufacturing capabilities in place to support advances in our drug development activities, such as new chemistries. While we believe our current capabilities and those we obtain through third-party manufacturers support our manufacturing needs now, it will be important to expand our manufacturing infrastructure in the future, which will likely require substantial expenditures. If we are not successful in executing this expansion, or if the demand for any of our commercial medicines exceeds our expectations, it could limit our ability to meet our manufacturing requirements and commercial objectives in the future. In addition, we have limited experience manufacturing pharmaceutical products of the chemical class represented by our medicines, called oligonucleotides, on a commercial scale for the systemic administration of a medicine. There are a small number of suppliers for certain capital equipment and raw materials that we use to manufacture our medicines, and some of these suppliers will need to increase their scale of production to meet our projected needs for commercial manufacturing. If a supplier chooses to devote more resources to other products, especially products with higher manufacturing capacity needs, that could impact such supplier’s capability to deliver our requirements timely. Further, we must continue to improve our manufacturing processes to allow us to reduce our drug costs. We or our partners may not be able to manufacture our medicines at a cost or in quantities necessary to make commercially successful products. Manufacturers, including us, must adhere to the FDA’s cGMP regulations and similar regulations in foreign countries, which the applicable regulatory authorities enforce through facilities inspection programs. We, our partners and our contract manufacturers may not comply or maintain compliance with cGMP, or similar foreign regulations. Non-compliance could significantly delay or prevent receipt of marketing authorizations for our medicines, including authorizations for our commercial medicines and our medicines in development, or could result in enforcement action after authorization that might limit the commercial success of our medicines. We rely on third-party manufacturers to supply the drug substance and drug product for TRYNGOLZA, DAWNZERA and WAINUA and drug product for WAYLIVRA. The operations of our suppliers, many of which are located outside of the United States, are subject to additional risks that are beyond our control. For example, tariffs on the raw materials, components, or equipment used to manufacture our products, or on our drug substance or finished products, will increase our manufacturing costs. On April 2, 2026, President Trump issued a proclamation that imposes tariffs of up to 100% on imported patented pharmaceutical products and active pharmaceutical ingredients, with specified exceptions. We are evaluating the potential impacts on our business related to the imposition of such tariffs but believe any impacts will be limited and manageable. In addition, merger and acquisition activity within the commercial manufacturing space could reduce the availability of resources from our third-party manufacturers. Delays or disruption to our own or third-party commercial manufacturing capabilities for any reason could limit the commercial success of our medicines. 44 Table of Contents Risks Related to the Development and Regulatory Approval of our Medicines If we or our partners fail to obtain regulatory approval for our medicines and additional approvals for our commercial medicines, we or our partners cannot sell them in the applicable markets. We cannot guarantee that any of our medicines will be considered safe and effective or will be approved for commercialization. In addition, it is possible that our commercial medicines may not be approved in additional markets or for additional indications. We and our partners must conduct time-consuming, extensive and costly clinical studies to demonstrate the safety and efficacy of each of our medicines before they can be approved or receive additional approvals for sale. We and our partners must conduct these studies in compliance with FDA regulations and with comparable regulations in other countries. We and our partners may not obtain necessary regulatory approvals on a timely basis, if at all, for our medicines. It is possible that regulatory authorities will not approve our medicines for marketing or our commercial medicines in additional markets or for additional indications. If the FDA or another regulatory authority believes that we or our partners have not sufficiently demonstrated the safety or efficacy of any of our medicines, including our commercial medicines or our medicines in development, the authority will not approve such medicine or will require additional studies, which could be time-consuming and expensive and delay or harm commercialization of the medicine. For example, in August 2018 we received a complete response letter from the FDA regarding the new drug application for WAYLIVRA in which the FDA determined that the safety concerns identified with WAYLIVRA in our clinical development program outweighed the expected benefits of triglyceride lowering in patients with FCS. We also received a Notice of Non-Compliance Withdrawal Letter, or Non-W, from Health Canada for WAYLIVRA in November 2018. The FDA or other comparable foreign regulatory authorities can delay, limit or deny approval of a medicine for many reasons, including: ● such authorities may disagree with the design or implementation of our clinical studies; ● we or our partners may be unable to satisfactorily demonstrate that a medicine is safe and effective for any indication; ● such authorities may not accept clinical data from studies conducted at clinical facilities that have deficient clinical practices or that are in countries where the standard of care is potentially different from that in the U.S.; ● we or our partners may be unable to demonstrate that our medicine’s clinical and other benefits outweigh its safety risks to support approval; ● such authorities may disagree with the interpretation of data from preclinical or clinical studies; ● such authorities may find deficiencies in the manufacturing processes or facilities of third-party manufacturers who manufacture clinical and commercial supplies for our medicines; and ● the approval policies or regulations of such authorities or their prior guidance to us or our partners during clinical development may significantly change in a manner rendering our clinical data insufficient for approval. Failure to receive marketing authorization for our medicines in development, or failure to receive additional marketing authorizations for our commercial medicines, or delays in these authorizations, could prevent or delay commercial introduction of the medicine, and, as a result, could negatively impact our ability to generate revenue from product sales. If the results of clinical testing indicate that any of our medicines are not suitable for commercial use, we may need to abandon one or more of our drug development programs. Drug discovery and drug development have inherent risks and the historical failure rate for drugs is high. Antisense medicines are a relatively new approach to therapeutics. If we cannot demonstrate that our medicines are safe and effective for human use in the intended indication(s), we may need to abandon one or more of our drug development programs. 45 Table of Contents Even if our medicines are successful in preclinical and human clinical studies, the medicines may not be successful in late-stage clinical studies. Similarly, topline, preliminary or interim data we release for any of our clinical studies may not be indicative of full or final results from such study.* Successful results in preclinical or initial human clinical studies, including the Phase 2 results for some of our medicines in development, may not predict the results of subsequent clinical studies. If any of our medicines in Phase 3 clinical studies do not show sufficient safety and efficacy in patients with the targeted indication, or if such studies are discontinued for any other reason, it could negatively impact our development and commercialization goals for these medicines and our stock price could decline. In addition, we may release topline, preliminary or interim data for any of our clinical studies. The interim, topline or preliminary results we report may differ from future results of the same studies, or different conclusions or considerations may qualify such results, once additional data have been received and fully evaluated. As a result, such data should be viewed with caution until the final data are available. In the past, we have invested in clinical studies of medicines that have not met the primary clinical endpoints in their Phase 3 studies or have been discontinued for other reasons. For example, in July 2026, we and AstraZeneca announced that the CARDIO-TTRansform Phase 3 trial for eplontersen in patients with ATTR-CM did not meet the primary efficacy endpoint of the composite outcome of cardiovascular, or CV, mortality and recurrent CV clinical events up to Week 140 compared with placebo. In October 2021, Biogen reported that QALSODY did not meet the primary clinical endpoint in the Phase 3 VALOR study; however, trends favoring QALSODY were seen across multiple secondary and exploratory measures of disease activity and clinical function. In addition, in March 2021, Roche decided to discontinue dosing in the Phase 3 GENERATION HD1 study of tominersen in patients with manifest Huntington’s disease based on the results of a pre-planned review of data from the Phase 3 study conducted by an unblinded Independent Data Monitoring Committee. Similar results could occur in clinical studies for our other medicines. There are a number of factors that could cause a clinical study to fail or be delayed, including: ● the clinical study may produce negative or inconclusive results; ● regulators may require that we hold, suspend or terminate clinical research for noncompliance with regulatory requirements; ● we, our partners, the FDA or foreign regulatory authorities could suspend or terminate a clinical study due to adverse side effects of a medicine on subjects or lack of efficacy in the trial; ● we or our partners may decide, or regulators may require us, to conduct additional preclinical testing or clinical studies; ● enrollment in our clinical studies may be slower than we anticipate; ● we or our partners, including our independent clinical investigators, contract research organizations and other third-party service providers on which we rely, may not identify, recruit or train suitable clinical investigators at a sufficient number of study sites or timely enroll a sufficient number of study subjects in the clinical study; ● the institutional review board for a prospective site might withhold or delay its approval for the study; ● people who enroll in the clinical study may later drop out due to adverse events, a perception they are not benefiting from participating in the study, fatigue with the clinical study process or personal issues; ● a clinical study site may deviate from the protocol for the study; ● the cost of our clinical studies may be greater than we anticipate; ● our partners may decide not to exercise any existing options to license and conduct additional clinical studies for our medicines; and ● the supply or quality of our medicines or other materials necessary to conduct our clinical studies may be insufficient, inadequate or delayed. Further, the FDA or other regulatory authorities could request, among other things, additional information or commitments before we can start or continue a clinical study, protocol amendments, increased safety monitoring, additional product labeling information, and post-approval commitments. This happened in connection with the conditional marketing approval for WAYLIVRA in the EU, as the European Commission is requiring us to conduct a post-authorization safety study to evaluate the safety of WAYLIVRA on thrombocytopenia and bleeding in FCS patients taking WAYLIVRA. In addition, under accelerated approval, the FDA is requiring completion of the ongoing Phase 3 trial for QALSODY to confirm the clinical benefit of QALSODY. Moreover, our commercial medicines are chemically similar to each other. As a result, a safety observation we encounter with one of our medicines could have, or be perceived by a regulatory authority to have, an impact on a different medicine we are developing. This could cause the FDA or other regulators to ask questions or take actions that could harm or delay our ability to develop and commercialize our medicines or increase our costs. Any failure or delay in our clinical studies could reduce the commercial potential or viability of our medicines. 46 Table of Contents We depend on third parties to conduct clinical studies for our medicines and any failure of those parties to fulfill their obligations could adversely affect our development and commercialization plans.* We depend on independent clinical investigators, contract research organizations and other third-party service providers to conduct our clinical studies for our medicines and expect to continue to do so in the future. For example, we use clinical research organizations, such as Icon Clinical Research Limited, Medpace, Inc., Parexel International Corporation, Syneos Health, Inc. and Thermo Fisher Scientific Inc. for the clinical studies for our medicines, including obudanersen, ulefnersen and zilganersen. We rely heavily on these parties for successful execution of our clinical studies, but do not control many aspects of their activities. For example, the investigators are not our employees, but we are responsible for ensuring that such investigators conduct each of our clinical studies in accordance with the general investigational plan and approved protocols for the study. Third parties may not complete activities on schedule or may not conduct our clinical studies in accordance with regulatory requirements or our stated protocols. For example, some of our key vendors have in the past experienced labor shortages, which impacted their ability to perform services for us for certain of our clinical trials. Subsequent failures of these third parties to carry out their obligations, or a termination of our relationship with such third parties, could delay or prevent the development, marketing authorization and commercialization of our medicines. In addition, while we do not have any clinical trial sites in Russia, Ukraine, Gaza or Iran, we do have a limited number of clinical trial sites in Israel, Turkey and Cyprus that may be materially impacted by the war between Russia and Ukraine and the armed conflict between the United States/Israel and Iran and surrounding areas, or collectively, conflicts in Eastern Europe and the Middle East, and could result in difficulties enrolling or completing our clinical trials in such areas on schedule. Since corporate partnering is part of our strategy to fund the advancement and commercialization of some of our development programs, if any of our collaborative partners fail to fund our collaborative programs, or if we cannot obtain additional partners, we may have to delay or stop progress on those drug development programs.* To date, corporate partnering has played a significant role in our strategy to fund our development programs and to add key development resources. While we are now commercializing some of our medicines independently, we still plan to continue to rely on additional collaborative arrangements to develop and commercialize some of our unpartnered medicines. However, we may not be able to negotiate favorable collaborative arrangements for these drug programs. If we cannot continue to secure additional collaborative partners, our revenues could decrease and the development of our medicines could suffer. Our corporate partners are developing and funding many of the medicines in our development pipeline. For example, we are relying on: ● AstraZeneca for the development and funding of WAINUA; ● Novartis for development and funding of pelacarsen; ● GSK for development and funding of bepirovirsen; ● Roche for development and funding of sefaxersen; and ● Otsuka for development and funding of ulefnersen. If any of these pharmaceutical companies stops developing and funding these medicines, our business could suffer and we may not have, or be willing to dedicate, the resources available to develop these medicines on our own. Our collaborators can terminate their relationships with us under certain circumstances, many of which are outside of our control. For example, in 2025, Novartis decided to return the clinical development program for a follow on to pelacarsen, and in 2022, Pfizer and Bayer decided to discontinue the clinical development programs for vupanorsen and fesomersen, respectively. Even with funding from corporate partners, if our partners do not effectively perform their obligations under our agreements with them, it would delay or stop the progress of our drug development and commercial programs. In addition to receiving funding, we enter into collaborative arrangements with third parties to: ● conduct clinical studies; ● seek and obtain marketing authorizations; and ● manufacture and commercialize our medicines. 47 Table of Contents Once we have secured a collaborative arrangement to further develop and commercialize one of our drug development programs, such as our collaborations with AstraZeneca, Biogen, GSK, Novartis, Otsuka and Roche, these collaborations may not continue or result in commercialized medicines, or may not progress as quickly as we anticipated. For example, a collaborator such as AstraZeneca, Biogen, GSK, Novartis, Otsuka or Roche, could determine that it is in its financial interest to: ● pursue alternative technologies or develop alternative products that may be competitive with the medicine that is part of the collaboration with us; ● pursue higher-priority programs or change the focus of its own development programs; or ● devote fewer resources to our medicines than it does to its own medicines. If any of these occur, it could affect our partner’s commitment to the collaboration with us and could delay or otherwise negatively affect the commercialization of our medicines, including DAWNZERA, QALSODY, SPINRAZA, WAINUA, bepirovirsen, sefaxersen, pelacarsen and ulefnersen. We may not be able to benefit from designations for our medicines from regulatory authorities that are intended to confer benefits such as financial incentives or an accelerated regulatory pathway.* In the U.S., under the Orphan Drug Act, the FDA may designate a medicine as an Orphan Drug if it is intended to treat a rare disease or condition affecting fewer than 200,000 individuals in the U.S. Orphan Drug designation does not convey any advantage in, or shorten the duration of, the regulatory review and approval process, but it can provide financial incentives, such as tax advantages and user-fee waivers, as well as longer regulatory exclusivity periods. The FDA has granted Orphan Drug designation to TRYNGOLZA for the treatment of patients with FCS, to WAINUA for the treatment of patients with ATTR, to obudanersen for the treatment of patients with Angelman syndrome, to salanersen for the treatment of patients with SMA, to sapablursen for the treatment of patients with PV, to ulefnersen for the treatment of patients with FUS-ALS, and to some of our earlier stage medicines. The FDA and EMA have granted Orphan Drug designation to DAWNZERA for the treatment of patients with HAE, to WAYLIVRA for the treatment of patients with FCS, and to some of our earlier stage medicines. In addition, the EMA has granted Orphan Drug designation to WAYLIVRA for the treatment of patients with FPL. Even if approval is obtained for a medicine that has been designated as an Orphan Drug, we may lose Orphan Drug exclusivity if the FDA or EMA determines that the request for designation was materially defective or if we cannot assure sufficient quantity of the applicable medicine to meet the needs of patients with the rare disease or condition, or if a competitor is able to gain approval for the same or a substantially similar medicine in a safer or more effective form or that makes a major contribution to patient care. If we lose Orphan Drug exclusivity on any of our medicines, we may face increased competition and lose market share for such medicine. We may also seek rare pediatric disease designation for some of our medicines. The FDA defines “rare pediatric disease” as a serious or life-threatening disease in which the serious or life-threatening manifestations primarily affect individuals aged from birth to 18 years or is a rare disease or condition within the meaning of the Orphan Drug Act. Designation of a medicine as a medicine for a rare pediatric disease does not guarantee that a marketing application for such medicine will meet the eligibility criteria for a rare pediatric disease priority review voucher, or PRV, at the time the application is approved. Under the Federal Food, Drug and Cosmetic Act, we will need to request a rare pediatric disease PRV in our original marketing application for any potential medicine for which we have received rare pediatric disease designation. The FDA may determine that a marketing application for any such medicine, if approved, does not meet the eligibility criteria for a PRV. Under the current statutory sunset provisions, the PRV program will sunset after September 30, 2029, and the FDA may not award PRVs under this program after such date. 48 Table of Contents Risks Associated with our Businesses as a Whole Risks related to our financial condition If we fail to obtain timely funding, we may need to curtail or abandon some of our programs. Many of our medicines are undergoing clinical studies or are in the early stages of research and development. Most of our programs will require significant additional research, development, manufacturing, preclinical and clinical testing, marketing authorizations, preclinical activities and commitment of significant additional resources prior to their successful commercialization. In addition, as we commercialize more medicines on our own, we will need to invest significant financial resources to continue developing the infrastructure required to successfully commercialize our medicines, including building and maintaining new support functions, scaling up existing internal support functions and expanding our manufacturing capabilities. All of these activities will require significant cash. As of June 30, 2026, we had cash, cash equivalents and short-term investments equal to $2.1 billion. If we or our partners do not meet our goals to successfully commercialize our medicines, including our commercial medicines, or to license certain medicines and proprietary technologies, we will need additional funding in the future. Our future capital requirements will depend on many factors such as: ● successful commercialization of our commercial medicines; ● the profile and launch timing of our medicines in development; ● changes in existing collaborative relationships and our ability to establish and maintain additional collaborative arrangements; ● continued scientific progress in our research, drug discovery and development programs; ● the size of our programs and progress with preclinical and clinical studies; ● the time and costs involved in obtaining marketing authorizations; ● competing technological and market developments, including the introduction by others of new therapies that address our markets; and ● our manufacturing requirements and capacity to fulfill such requirements. If we need additional funds, we may need to raise them through public or private financing. Additional financing may not be available on acceptable terms or at all. If we raise additional funds by issuing equity securities, the shares of existing stockholders will be diluted and the price, as well as the price of our other securities, may decline. For example, in September 2024, we completed an underwritten public offering of 11,500,000 shares of our common stock for total net proceeds, after deducting underwriting discounts and commissions and other offering expenses payable by us, of approximately $489.1 million. If adequate funds are not available or not available on acceptable terms, we may have to cut back on one or more of our research, drug discovery or development programs, or commercial operations. Alternatively, we may obtain funds through arrangements with collaborative partners or others, which could require us to give up rights to certain of our technologies or medicines. We have incurred losses, and our business will suffer if we fail to consistently achieve profitability in the future. Because drug discovery and development require substantial lead-time and money prior to commercialization, our expenses have generally exceeded our revenue since we were founded in January 1989. As of June 30, 2026, we had an accumulated deficit of approximately $2.8 billion and stockholders’ equity of approximately $0.4 billion. Most of our income has historically come from collaborative arrangements, including commercial revenue from royalties and R&D revenue, with additional income from research grants and the sale or licensing of our patents, as well as interest income. We will need to continue investing significant financial resources to commercialize medicines on our own, and we expect our future revenue to be driven primarily by commercial sales. If we do not earn substantial revenue from commercial sales, we may incur additional operating losses in the future, which could restrict our ability to successfully develop additional medicines or sustain future profitability. We may not be entitled to obtain additional milestone payments under our royalty monetization agreement with Royalty Pharma. In January 2023, we entered into a Royalty Purchase Agreement with Royalty Pharma Investments. In addition to the $500 million we received at closing, this agreement makes available to us up to an additional $625 million in milestone payments. However, these additional milestone payments are subject to satisfaction of certain conditions related to the regulatory approval or commercial sales of pelacarsen, in certain cases by specific deadlines. Should we not satisfy such conditions by the applicable deadlines, or if we fail to meet our obligations or default under this agreement, the actual amount of additional payments to us could be substantially less than the maximum amounts available thereunder. 49 Table of Contents Risks related to our intellectual property If we cannot protect our patent rights or our other proprietary rights, others may compete more effectively against us.* Our success depends to a significant degree upon whether we can continue to develop, secure and maintain intellectual property rights to proprietary products and services. However, we may not receive issued patents on any of our pending patent applications in the U.S. or in other countries and we may not be able to obtain, maintain or enforce our patents and other intellectual property rights, any of which could impact our ability to compete effectively. In addition, the scope of any of our issued patents may not be sufficiently broad to provide us with a competitive advantage. Furthermore, other parties may successfully challenge, invalidate or circumvent our issued patents or patents licensed to us so that our patent rights do not create an effective competitive barrier or revenue source. For example, on June 22, 2026, Biogen, Cold Spring Harbor Laboratory, and Ionis filed a patent infringement lawsuit in the District Court of Delaware following notice that Somerset Therapeutics, LLC had filed an Abbreviated New Drug Application, or ANDA, seeking approval to commercialize a generic version of SPINRAZA and alleging that certain patents covering SPINRAZA and its use are invalid or would not be infringed. If Somerset Therapeutics obtains a favorable ruling in such lawsuit, our revenues from SPINRAZA could be materially adversely affected. We cannot be certain that the U.S. Patent and Trademark Office, or U.S. PTO, and courts in the U.S. or the patent offices and courts in foreign countries will consider the claims in our patents and applications covering our commercial medicines, or any of our medicines in development, as patentable. Method-of-use patents protect the use of a product for the specified method. This type of patent does not prevent a competitor from making and marketing a product that is identical to our product for an indication that is outside the scope of the patented method. Moreover, even if competitors do not actively promote their product for our targeted indications, physicians may prescribe these products off-label. Although off-label prescriptions may infringe or contribute to the infringement of method-of-use patents, the practice is common and such infringement is difficult to prevent, even through legal action. If we or any licensor partner loses or cannot obtain patent protection for our commercial medicines or any of our medicines in development, it could have a material adverse impact on our business. Intellectual property litigation could be expensive and prevent us from pursuing our programs.* From time to time, we have to defend our intellectual property rights. If we are involved in an intellectual property dispute, we may need to litigate to defend our rights or assert them against others. Disputes can involve arbitration, litigation or proceedings declared by the U.S. PTO or the International Trade Commission or foreign patent authorities. Even if resolved in our favor, litigation or other legal proceedings relating to intellectual property claims may cause us to incur significant expenses and could distract our technical and management personnel from their normal responsibilities. In addition, there could be public announcements of the results of hearings, motions or other interim proceedings or developments and if securities analysts or investors perceive these results to be negative, it could have a substantial adverse effect on the price of our common stock. For example, in September 2025, we filed a claim against Arrowhead Pharmaceuticals, Inc., or Arrowhead, for patent infringement over Arrowhead’s commercialization of plozasiran, and Arrowhead filed a counterclaim against us seeking to invalidate that same patent. We are also a party to ongoing litigation involving a third party seeking regulatory approval to commercialize a generic version of SPINRAZA in the U.S. as described above. For details regarding these proceedings, refer to Part II, Item 1, Legal Proceedings. If a third party claims that our medicines or technology infringe its patents or other intellectual property rights, we may have to discontinue an important product or product line, alter our products and processes, pay license fees or cease certain activities. We may not be able to obtain a license to needed intellectual property on favorable terms, if at all. There are many patents issued or applied for in the biotechnology industry, and we may not be aware of patents or patent applications held by others that relate to our business. This is especially true since patent applications in the U.S. are filed confidentially for the first 18 months. Moreover, the validity and breadth of biotechnology patents involve complex legal and factual questions for which important legal issues remain. Risks related to product liability We are exposed to potential product liability claims, and insurance against these claims may not be available to us at a reasonable rate in the future or at all. Our business exposes us to potential product liability risks that are inherent in the testing, manufacturing, marketing and sale of therapeutic products, including potential product liability claims related to our commercial medicines and our medicines in development. We have clinical study insurance coverage and commercial product liability insurance coverage. However, this insurance coverage may not be adequate to cover claims against us, or be available to us at an acceptable cost, if at all. Regardless of their merit or eventual outcome, product liability claims may result in decreased demand for our medicines, injury to our reputation, withdrawal of clinical study volunteers and loss of revenues. Thus, whether or not we are insured, a product liability claim or product recall may result in losses that could be material. 50 Table of Contents Risks related to our personnel The loss of key personnel, or the inability to attract and retain highly skilled personnel, could make it more difficult to run our business and reduce our likelihood of success. We are dependent on the principal members of our management, scientific and commercial staff. We do not have employment agreements with any of our employees that would prevent them from leaving us. The loss of our key management, scientific or commercial employees might slow the achievement of important research and development or commercial goals. It is also critical to our success that we recruit and retain qualified scientific personnel to perform research and development work and that we recruit and retain qualified marketing, sales, market access, distribution, and related personnel to commercialize our medicines. We may not be able to attract and retain skilled and experienced personnel on acceptable terms because of intense competition for experienced personnel among many pharmaceutical and health care companies, universities and non-profit research institutions. In addition, failure to succeed in clinical studies or in commercializing our medicines may make it more challenging to recruit and retain qualified personnel. Risks related to health epidemics, climate change and other events Our business may be adversely affected by health epidemics, climate change, extreme weather events, fires, earthquakes, war, civil or political unrest, terrorism or disruptions of the U.S. government. Our business could be adversely affected by health epidemics in regions where we or our partners are commercializing our medicines, have concentrations of clinical trial sites or other business operations, and could cause disruption in the operations of third-party manufacturers and contract research organizations upon whom we rely. For example, enrollment in some of our clinical trials was delayed due to the COVID-19 pandemic. In recent years, extreme weather events and changing weather patterns have become more common. As a result, we are potentially exposed to varying natural disaster or extreme weather risks such as fires, hurricanes, tornadoes, droughts, floods, or other events that may result from the impact of climate change on the environment, any of which could impact our business and manufacturing operations. The potential impacts of climate change may also include increased operating costs associated with additional regulatory requirements and investments in reducing energy, water use and greenhouse gas emissions. In addition, we currently manufacture most of our research and clinical supplies in a manufacturing facility located in Carlsbad, California, and various regions within California have experienced numerous catastrophic wildfires. We manufacture the finished drug product for TRYNGOLZA, DAWNZERA and WAYLIVRA at third-party contract manufacturers. Biogen manufactures the finished drug product for SPINRAZA and QALSODY and AstraZeneca is responsible for WAINUA’s commercial drug supply. The facilities and the equipment we, our partners and our contract manufacturers use to research, develop and manufacture our medicines would be costly to replace and could require substantial lead time to repair or replace. Our facilities or those of our partners or contract manufacturers may be harmed by natural disasters or other events outside our control, such as earthquakes, war, civil or political unrest, deliberate acts of sabotage, terrorism or industrial accidents such as fire and explosion, whether due to human or equipment error, and if such facilities are affected by a disaster or other event, our development and commercialization efforts would be delayed. Although we possess property damage and business interruption insurance coverage, this insurance may not be sufficient to cover all of our potential losses and may not continue to be available to us on acceptable terms, or at all. In addition, our development and commercialization activities could be harmed or delayed by staffing shortages or a shutdown or other significant disruption of the U.S. government, including the FDA or the U.S. PTO. 51 Table of Contents Risks related to personal information, cybersecurity, social media and artificial intelligence We are dependent on data as well as information technology systems and infrastructure, which exposes us to data protection risks. We are dependent upon our own and third-party data as well as information technology systems and infrastructure, including mobile technologies, to operate our business. The personal information we process subjects us to stringent and evolving U.S. and foreign laws, rules and regulations, contractual obligations, industry standards and other obligations related to data privacy and security. Our obligations (including in relation to personal information) require us to maintain certain practices, including those in relation to cross-border transfers of data. The multitude and complexity of our information technology systems and infrastructure (including those of third parties with whom we work) make them vulnerable to a variety of evolving threats that may result in systems or data interruption, corruption, destruction, disruption of data integrity, malicious intrusion, or random attacks or other compromise (such as due to malfunctions, software vulnerabilities, natural disasters, telecommunications failures, malicious actors and personnel error). Data privacy or security incidents or breaches pose a risk that sensitive data, including our intellectual property, trade secrets or personal information of our employees, patients, customers or other business partners may be exposed to unauthorized persons. Cyber-attacks are increasing in their frequency, sophistication and intensity, particularly as companies (including us) continue to leverage remote work structures. In addition, the number and frequency of cybersecurity events globally may be heightened during times of geopolitical tension or instability between countries, including, for example, the ongoing conflicts in Eastern Europe and the Middle East, as well as related political or economic responses and counter-responses by various global actors. Cybersecurity related events could include the deployment or use of harmful malware or malicious code, denial-of-service attacks, credential stuffing attacks, credential harvesting attacks, social engineering attacks (including deep fakes and phishing attacks), ransomware and other means to affect, as applicable, the confidentiality, privacy, security, integrity or availability of our data as well as information systems and infrastructure (including that of third parties with whom we work). Our current, past and prospective business partners face similar risks and any security breaches of their systems (or those of third parties upon which they rely) could adversely affect our security posture. A security breach or a violation of obligations related to privacy or cybersecurity (including perceived breaches or violations) could result in any of the following, any of which could disrupt our business and result in increased costs or loss of revenue: ● harm our reputation; ● delay progress on the development of our medicines; ● compel us to comply with applicable security or data breach notification obligations (including laws); ● result in the diversion of monetary funds and other company resources; ● subject us to financial or other penalties, regulatory investigations or actions, including mandatory and costly corrective actions, and otherwise subject us to litigation or other liabilities; and ● require us to verify the correctness of database contents. Risk mitigation strategies such as liability limitations in our contracts and insurance coverage may prove inadequate if there is a security breach or privacy violation. We do not maintain cyber insurance. While we have invested, and continue to invest, in the protection of our data and information technology systems and infrastructure as well as our compliance with relevant privacy and cybersecurity obligations, our efforts may not be successful. Non-compliance with relevant data protection obligations or a failure to secure our data, information technology systems or infrastructure could adversely affect our business and operations and result in the loss of critical or sensitive information, which could result in financial, legal, business or reputational harm to us. The increasing use of social media platforms presents new risks and challenges. Social media is increasingly being used to communicate about our medicines and the diseases our therapies are designed to treat. Social media practices in the biopharmaceutical industry continue to evolve and regulations relating to such use are not always clear and create uncertainty and risk of noncompliance with regulations applicable to our business. Despite our efforts to provide guidelines and training to our employees regarding social media use and monitor social media communications, there is risk that the unauthorized use of social media by our employees to communicate about our products or business, or any inadvertent disclosure of material, nonpublic information through these means, may result in violations of applicable laws and regulations, which may result in significant legal and financial exposure and reputational damages that could have a material adverse impact on our business. Furthermore, negative posts or comments about us or our medicines on social media could seriously damage our reputation, brand image and goodwill. If any of these events were to occur or we otherwise fail to comply with applicable regulations, we could incur liability, face restrictive regulatory actions or incur other harm to our business. 52 Table of Contents We use artificial intelligence in certain aspects of our business, and challenges with properly managing its use could adversely affect our business. We incorporate artificial intelligence, or AI, solutions into certain aspects of our business, and applications of AI may become important in our operations over time. Our competitors or other third parties may incorporate AI into their businesses more quickly or more successfully than us, which could impair our ability to compete effectively and adversely affect our results of operations. There are also significant risks involved in developing and deploying AI, and there can be no assurance that the usage of AI will enhance our medicines or the discovery or development of our product candidates or be beneficial to our business, including our efficiency or profitability. It is also uncertain how various laws will apply to content generated by AI. Various government authorities have proposed or enacted laws governing the development and use of AI technologies. We are subject to the risks of new or enhanced governmental or regulatory scrutiny, litigation, or other legal liability, ethical concerns, negative consumer perceptions as to automation and AI, or other complications that could adversely affect our business, reputation, or financial results. Risks related to our securities and the global credit markets If we do not progress in our programs as anticipated, the price of our securities could decrease. For planning purposes, we estimate and may disclose the timing of a variety of clinical, regulatory and other milestones, such as when we anticipate a certain medicine will enter clinical trials, when we anticipate disclosing clinical data, when we anticipate completing a clinical study, when we anticipate filing an application for, or obtaining, marketing authorization, or when we or our partners plan to commercially launch a medicine. We base our estimates on present facts and a variety of assumptions, many of which are outside of our control. If we do not achieve milestones in accordance with our or our investors’ or securities analysts’ expectations, including milestones related to our commercial medicines and medicines in development, the price of our securities could decrease. In addition, our share price may be dependent upon the valuations and recommendations of the analysts who cover our business. If our results do not meet these analysts’ forecasts, the expectations of our investors or the financial guidance we provide to investors in any period, the market price of our common stock could decline. Our ability to meet analysts’ forecasts, investors’ expectations and our financial guidance is substantially dependent on our ability to maintain or increase sales of our commercial medicines, both partnered and unpartnered. If the price of our securities continues to be highly volatile, this could make it harder to liquidate your investment and could increase your risk of suffering a loss. The market price of our common stock, like that of the securities of many other biopharmaceutical companies, has been and is likely to continue to be highly volatile. These fluctuations in our common stock price may significantly affect the trading price of our securities. During the 12 months preceding June 30, 2026, the closing market price of our common stock ranged from $86.50 to $39.94 per share. Many factors can affect the market price of our securities, including, for example, fluctuations in our operating results, financing transactions, announcements related to collaborations, clinical study results, technological innovations or new products being developed by us or our competitors, the commercial success of our approved medicines, governmental regulation, marketing authorizations, changes in payers’ reimbursement policies, developments in patent or other proprietary rights and public concern regarding the safety of our medicines. Broad market factors may materially harm the market price of our common stock irrespective of our operating performance. For example, events such as recent tariffs announcements and the ongoing conflicts in Eastern Europe and the Middle East have caused disruptions of global financial markets and resulted in increased volatility in the trading price of our common stock. In addition, industry factors may materially harm the market price of our common stock. Nasdaq, and the market for biotechnology companies in particular, have historically experienced extreme price and volume fluctuations that have often been unrelated or disproportionate to the operating performance of the particular companies affected. The trading prices and valuations of these stocks, and of ours, may not be predictable. A loss of investor confidence in the market for biotechnology or pharmaceutical stocks or the stocks of other companies that investors perceive to be similar to us, the opportunities in the biotechnology and pharmaceutical market or the stock market in general, could depress our stock price regardless of our business, prospects, financial conditions or results of operations. 53 Table of Contents Negative conditions in the global economy, credit markets and financial services and other industries may adversely affect our business, financial condition or stock price.* The global economy, credit and financial markets have experienced extreme volatility and disruptions recently, including as a result of tariffs announcements and the ongoing conflicts in Eastern Europe and the Middle East. These disruptions can result in severely diminished liquidity and credit availability, declines in consumer confidence, declines in economic growth, increases in unemployment rates, increases in inflation rates, disruptions of the global supply chain and energy markets and uncertainty about economic stability. Any such volatility and disruptions may have adverse consequences on us or the third parties on whom we rely. There can be no assurance that further deterioration in the global economy, credit and financial markets and confidence in economic conditions will not occur. If the current equity and credit markets deteriorate, it may make any necessary debt or equity financing more difficult, more costly and more dilutive. Failure to secure any necessary financing in a timely manner and on favorable terms could have a material adverse effect on our operations, growth plans, financial performance or stock price. In addition, our insurance carriers and insurance policies covering all aspects of our business may become financially unstable or may not be sufficient to cover any or all of our losses and may not continue to be available to us on acceptable terms, or at all. A variety of risks associated with operating our business and marketing our medicines internationally could adversely affect our business. In addition to our U.S. operations, we are commercializing WAYLIVRA in the EU, Latin America and certain Caribbean countries. We face risks associated with our international operations, including possible unfavorable regulatory, pricing and reimbursement, political, tax and labor conditions, which could harm our business. Because we have international operations, we are subject to numerous risks associated with international business activities, including: ● compliance with differing or unexpected regulatory requirements for our medicines and foreign employees; ● complexities associated with managing multiple payer reimbursement regimes, government payers or patient self-pay systems; ● difficulties in staffing and managing foreign operations; ● in certain circumstances, increased dependence on the commercialization efforts and regulatory compliance of third-party distributors or strategic partners; ● foreign government taxes, regulations and permit requirements; ● U.S. and foreign government tariffs, trade and export restrictions, price and exchange controls and other regulatory requirements; ● U.S. restrictions on the use of certain foreign biotech equipment and service providers, such as those set forth in the BIOSECURE Act; ● anti-corruption laws, including the Foreign Corrupt Practices Act, or the FCPA, and its equivalent in foreign jurisdictions; ● economic weakness, including inflation, natural disasters, war, acts of terrorism, political instability or public health issues or health epidemics, in particular foreign countries or globally; ● fluctuations in currency exchange rates, which could result in increased operating expenses and reduced revenue, and other obligations related to doing business in another country; ● the potential for a local seller, faced with higher local prices, importing medicines from an international market with lower prices rather than buying such medicines locally, which is referred to as parallel importation; ● compliance with tax, employment, privacy, immigration and labor laws, regulations and restrictions for employees living or traveling abroad; ● workforce uncertainty in countries where labor unrest is more common than in the U.S.; and ● changes in diplomatic and trade relationships. Our business activities outside of the U.S. are subject to the FCPA and similar anti-bribery or anti-corruption laws, regulations or rules of other countries in which we operate, including the United Kingdom’s Bribery Act 2010. In many other countries, the healthcare providers who prescribe pharmaceuticals are employed by their government, and the purchasers of pharmaceuticals are government entities; therefore, any dealings with these prescribers and purchasers may be subject to regulation under the FCPA. There is no certainty that all employees and third-party business partners (including our contract research organizations, contract manufacturing organizations, distributors, wholesalers, agents, contractors and other partners) will comply with anti-bribery laws. Importantly, we do not control the actions of manufacturers and other third-party agents, although we may be liable for their actions. Violation of these laws may result in civil or criminal sanctions, which could include monetary fines, criminal penalties, and disgorgement of past profits, which could have an adverse impact on our business and financial condition. 54 Table of Contents Provisions in our certificate of incorporation, bylaws and convertible notes documents and Delaware law may prevent stockholders from receiving a premium for their shares.* Our certificate of incorporation provides for classified terms for the members of our board of directors. Our certificate also includes a provision that requires at least 66 2/3 percent of our voting stockholders to approve a merger or certain other business transactions with, or proposed by, any holder of 15 percent or more of our voting stock, except in cases where certain directors approve the transaction or certain minimum price criteria and other procedural requirements are met. Our certificate of incorporation also requires that any action required or permitted to be taken by our stockholders must be taken at a duly called annual or special meeting of stockholders and may not be taken by written consent. In addition, only our board of directors, chairperson of the board or chief executive officer can call special meetings of our stockholders. We have in the past, and may in the future, implement a stockholders’ rights plan, also called a poison pill, which could make it uneconomical for a third party to acquire our company on a hostile basis. In addition, our board of directors has the authority to fix the rights and preferences of, and issue shares of preferred stock, which may have the effect of delaying or preventing a change in control of our company without action by our stockholders. The provisions of our convertible senior notes could make it more difficult or more expensive for a third party to acquire us. Upon the occurrence of certain transactions constituting a fundamental change, holders of the notes will have the right, at their option, to require us to repurchase all of their notes or a portion of their notes, which may discourage certain types of transactions in which our stockholders might otherwise receive a premium for their shares over the then-current market prices. As of June 30, 2026, we had two outstanding convertible senior notes, our 0% Notes due 2030, which mature in December 2030, and our 1.75% Notes due 2028, which mature in June 2028. Additionally, in connection with the issuance of our 0% Notes due 2026, we entered into certain call spread transactions consisting of convertible note hedges, which were exercised in April 2026, and warrant transactions, which became exercisable commencing on July 1, 2026. The terms of the warrant transactions are subject to adjustment in connection with certain events, including upon the announcement of certain mergers or other business transactions involving us. In addition, the warrants may be required to be settled or unwound in connection with a merger or other business transaction involving us, which could make an acquisition of our company significantly more expensive to the purchaser. These provisions, as well as Delaware law, including Section 203 of the Delaware General Corporation Law, and other of our agreements, may discourage certain types of transactions in which our stockholders might otherwise receive a premium for their shares over then-current market prices, and may limit the ability of our stockholders to approve transactions that they think may be in their best interests. Future sales of our common stock in the public market could adversely affect the trading price of our securities.* Future sales of substantial amounts of our common stock in the public market, or the perception that such sales could occur, could adversely affect trading prices of our securities. For example, we may issue approximately 18.6 million shares of our common stock upon conversion of our 0% Notes due 2030 and 1.75% Notes due 2028. In connection with the issuance of the 0% Notes due 2026, we entered into certain call spread transactions consisting of convertible note hedges and warrant transactions covering 10.9 million shares. The convertible note hedges offset the dilution to holders of common stock that arose from the conversion of those notes. However, the anti-dilutive effect of the convertible note hedges is offset by the related warrant transactions, which became exercisable commencing on July 1, 2026. The addition of any of these shares into the public market may have an adverse effect on the price of our securities. In addition, in connection with the warrant transactions, the counterparties may modify their hedge positions from time to time, including during the exercise period, by purchasing and selling shares of our common stock, other of our securities, or other instruments, including over-the-counter derivative instruments, that they may wish to use in connection with such hedging, which may have an adverse impact on the trading price of our common stock. 55 Table of Contents Risks related to compliance with laws Our operations are subject to extensive legal and regulatory requirements affecting the health care industry. Our operations are subject to extensive legal and regulatory requirements affecting the health care industry, including federal, state, and foreign fraud and abuse (including anti-kickback laws and false claims laws), transparency laws, such as the federal Sunshine Act, and health information privacy and security laws, which are subject to change at any time. It is possible that government authorities will conclude that our business practices may not comply with current or future statutes, regulations or case law involving applicable fraud and abuse or other healthcare laws and regulations. Penalties for violations of applicable healthcare laws and regulations may include significant civil, criminal and administrative penalties, damages, disgorgement, fines, imprisonment, exclusion of products from government funded healthcare programs, such as Medicare and Medicaid, and additional reporting requirements and oversight if we enter into a corporate integrity agreement or similar agreement to resolve allegations of non-compliance with these laws. In addition, violations may also result in reputational harm, diminished profits and future earnings. Because we use biological materials, hazardous materials, chemicals and radioactive compounds, if we do not comply with laws regulating the protection of the environment and health and human safety, our business could be adversely affected. Our research, development and manufacturing activities involve the use of potentially harmful biological materials as well as materials, chemicals and various radioactive compounds that could be hazardous to human health and safety or the environment. We store most of these materials and various wastes resulting from their use at our facilities in Carlsbad, California pending ultimate use and disposal. We cannot completely eliminate the risk of contamination, which could cause: ● interruption of our research, development and manufacturing efforts; ● injury to our employees and others; ● environmental damage resulting in costly clean up; and ● liabilities under federal, state and local laws and regulations governing health and human safety, as well as the use, storage, handling and disposal of these materials and resultant waste products. In such an event, we may be held liable for any resulting damages, and any liability could exceed our resources. Although we carry insurance for pollution liability in amounts and types that we consider commercially reasonable, the coverage or coverage limits of our insurance policies may not be adequate. If our losses exceed our insurance coverage, our financial condition would be adversely affected. Our business is subject to changing regulations for corporate governance and public disclosure that has increased both our costs and the risk of noncompliance. Each year we are required to evaluate our internal control systems to allow management to report on, and our Independent Registered Public Accounting Firm to attest to, our internal controls as required by Section 404 of the Sarbanes-Oxley Act. As a result, we continue to incur additional expenses and divert our management’s time to comply with these regulations. In addition, if we cannot continue to comply with the requirements of Section 404 in a timely manner, we might be subject to sanctions or investigation by regulatory authorities, such as the SEC, the Public Company Accounting Oversight Board, or PCAOB, or The Nasdaq Global Select Market. Any such action could adversely affect our financial results and the market price of our common stock. The SEC and other regulators have continued to adopt new rules and regulations and make additional changes to existing regulations that require our compliance. In July 2010, the Dodd-Frank Wall Street Reform and Protection Act, or the Dodd-Frank Act, was enacted, and in August 2022, the SEC adopted additional rules and regulations under the Dodd-Frank Act related to “say on pay” and proxy access. Stockholder activism, the current political environment and the current high level of government intervention and regulatory reform may lead to substantial new regulations and disclosure obligations, which has and may in the future lead to additional compliance costs and impact the manner in which we operate our business. Risks related to taxes Our ability to use our net operating loss carryovers and certain other tax attributes may be limited. Under the Internal Revenue Code of 1986, as amended, or the Code, a corporation is generally allowed a deduction for net operating losses, or NOLs, carried over from a prior taxable year. Under the Code, we can carry forward our NOLs to offset our future taxable income, if any, until such NOLs are used or expire. The same is true of other unused tax attributes, such as tax credits. 56 Table of Contents Under the current U.S. federal income tax law, U.S. federal NOLs generated in taxable years beginning after December 31, 2017 may be carried forward indefinitely, but the deductibility of such U.S. federal NOLs is limited to 80 percent of taxable income. In addition, under Sections 382 and 383 of the Code, and corresponding provisions of state law, if a corporation undergoes an “ownership change,” which is generally defined as a greater than 50 percentage-point cumulative change, by value, in its equity ownership over a three-year period, the corporation’s ability to use its pre-change NOL carryforwards and other pre-change tax attributes to offset its post-change income or taxes may be limited. We may experience ownership changes in the future as a result of subsequent shifts in our stock ownership, some of which may be outside of our control. If an ownership change occurs and our ability to use our NOL carryforwards or other tax attributes is materially limited, it would harm our future operating results by effectively increasing our future tax obligations. As a result of our merger with Akcea Therapeutics, Inc. in 2020, or the Akcea Merger, we are subject to the separate return limitation year, or SRLY, rules. Under the SRLY rules, our utilization of Akcea’s pre-merger NOL and tax credit carryforwards is limited to the amount of income that Akcea contributes to our consolidated taxable income. The Akcea pre-merger tax attributes cannot be used to offset any of the income that Ionis contributes to our consolidated taxable income. In addition, at the state level, there may be periods during which the use of NOLs is suspended or otherwise limited, which could accelerate or permanently increase state taxes owed. For example, in June 2024, California enacted Senate Bill 167, or SB 167, which, with certain exceptions, suspends the ability to use California net operating losses to offset California income and limits the ability to use California business tax credits to offset California taxes, for taxable years beginning after 2023 and before 2027. Our future taxable income could be impacted by changes in tax laws, regulations and treaties. A change in tax laws, treaties or regulations, or their interpretation, of any country in which we operate could materially affect us. We could be subject to additional tax liabilities. We are subject to U.S. federal, state, local and foreign income taxes, sales taxes in the U.S., withholding taxes and transaction taxes in foreign jurisdictions. Significant judgment is required in evaluating our tax positions and our worldwide provision for taxes. During the ordinary course of business, there are many activities and transactions for which the ultimate tax determination is uncertain. In addition, our tax obligations and effective tax rates could be adversely affected by changes in the relevant tax, accounting and other laws, regulations, principles and interpretations, including those relating to income tax nexus, by recognizing tax losses or lower than anticipated earnings in jurisdictions where we have lower statutory rates and higher than anticipated earnings in jurisdictions where we have higher statutory rates, by changes in foreign currency exchange rates, or by changes in the valuation of our deferred tax assets and liabilities. In particular, our tax obligations and effective tax rate in the jurisdictions in which we conduct business could increase in the future as a result of the base erosion and profit shifting, or BEPS, project led by the Organization for Economic Co-operation and Development, or OECD, and other initiatives led by the OECD or the European Commission. The OECD is leading work on an iteration of the BEPS project based on two “pillars” (subject to certain revenue thresholds), involving, among other measures, the reallocation of taxing rights in respect of certain multinational enterprises above a fixed profit margin to the jurisdictions in which they carry on business (referred to as “Pillar One”) and imposition of a minimum effective corporate tax rate on certain multinational enterprises (referred to as “Pillar Two”). A number of countries in which we conduct business have enacted, or are in the process of enacting, core elements of the Pillar Two rules (with further provisions expected to be enacted in the future). Based on the minimum revenue thresholds we currently expect to fall within the scope of these requirements in the near term. The OECD has issued (and is expected to continue to issue further) administrative guidance providing transition and safe harbor rules in relation to the implementation of the Pillar Two proposal. For example, in January 2026, the OECD issued administrative guidance providing for, among other things, a side-by-side framework intended to limit the application of Pillar Two top-up taxes to U.S.-parented groups; however, the ultimate impact will depend on jurisdictional adoption and further guidance. We are monitoring developments and evaluating the potential impacts of the Pillar Two rules, including on our effective tax rates, and considering our eligibility to qualify for these safe harbor rules (including under the proposed “side-by-side” arrangement). We may be audited in various jurisdictions, and such jurisdictions may assess additional income, sales and value-added or other taxes against us. In addition, we are currently under examination by the Internal Revenue Service for tax year 2023. Although we believe our tax estimates are reasonable, the final determination of any tax audits or litigation could be materially different from our historical tax provisions and accruals, which could have a material adverse effect on our operating results or cash flows in the period for which a determination is made. 57 Table of Contents