GBDC

The information contained in this section should be read in conjunction with our unaudited interim consolidated financial statements and related notes thereto appearing elsewhere in this Quarterly Report on Form 10-Q. In this report, “we,” “us,” “our” and “Golub Capital BDC” refer to Golub Capital BDC, Inc. and its consolidated subsidiaries. Forward-Looking Statements Some of the statements in this Quarterly Report on Form 10-Q constitute forward-looking statements, which relate to future events or our future performance or financial condition. The forward-looking statements contained in this Quarterly Report on Form 10-Q involve risks and uncertainties, including statements as to: •our future operating results; •our business prospects and the prospects of our portfolio companies, including our and their ability to achieve our respective objectives due to disruptions, including, without limitation, those caused by global health pandemics, or other large scale events; •the effect of investments that we expect to make and the competition for those investments; •our contractual arrangements and relationships with third parties; •actual and potential conflicts of interest with GC Advisors LLC, or GC Advisors, and other affiliates of Golub Capital LLC, or collectively, Golub Capital; •the dependence of our future success on the general economy and its effect on the industries in which we invest; •the ability of our portfolio companies to achieve their objectives; •the use of borrowed money to finance a portion of our investments; •the adequacy of our financing sources and working capital; •the timing of cash flows, if any, from the operations of our portfolio companies; •general economic and political trends and other external factors; •changes in political, economic or industry conditions, the interest rate environment or conditions affecting the financial and capital markets that could result in changes to the value of our assets; •elevated levels of inflation, and its impact on us, on our portfolio companies and on the industries in which we invest; •the ability of GC Advisors to locate suitable investments for us and to monitor and administer our investments; •the ability of GC Advisors or its affiliates to attract and retain highly talented professionals; •the ability of GC Advisors to continue to effectively manage our business due to disruptions, including those caused by global health pandemics, or other large scale events; •turmoil in Ukraine, Russia and the Middle East, including sanctions related to such turmoil, and the potential for volatility in energy prices and other supply chain issues and any impact on the industries in which we invest; •our ability to qualify and maintain our qualification as a regulated investment company, or RIC, and as a business development company; •the impact of information technology systems and systems failures, including data security breaches, data privacy compliance, network disruptions, and cybersecurity attacks; •general price and volume fluctuations in the stock markets; •the impact on our business of the Dodd-Frank Wall Street Reform and Consumer Protection Act, or Dodd-Frank, and the rules and regulations issued thereunder and any actions toward repeal thereof; and •the effect of changes to tax legislation and our tax position. 148 TABLE OF CONTENTS Such forward-looking statements may include statements preceded by, followed by or that otherwise include the words “may,” “might,” “will,” “intend,” “should,” “could,” “can,” “would,” “expect,” “believe,” “estimate,” “anticipate,” “predict,” “potential,” “plan” or similar words. The forward-looking statements contained in this Quarterly Report on Form 10-Q involve risks and uncertainties. Our actual results could differ materially from those implied or expressed in the forward-looking statements for any reason, including the factors set forth as “Risk Factors” in our Annual Report on Form 10-K for the year ended September 30, 2025. We have based the forward-looking statements included in this report on information available to us on the date of this report. Actual results could differ materially from those anticipated in our forward-looking statements and future results could differ materially from historical performance. You are advised to consult any additional disclosures that we make directly to you or through reports that we have filed or in the future file with the Securities and Exchange Commission, or the SEC, including Annual Reports on Form 10-K, Registration Statements on Form N-2, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K. This Quarterly Report on Form 10-Q contains statistics and other data that have been obtained from or compiled from information made available by third-party service providers. We have not independently verified such statistics or data. 149 TABLE OF CONTENTS Overview We are an externally managed, closed-end, non-diversified management investment company that has elected to be regulated as a business development company under the Investment Company Act of 1940, as amended, or the 1940 Act. In addition, for U.S. federal income tax purposes, we have elected to be treated as a RIC under Subchapter M of the Internal Revenue Code of 1986, as amended, or the Code. As a business development company and a RIC, we are also subject to certain constraints, including limitations imposed by the 1940 Act and the Code. Our shares are currently listed on The Nasdaq Global Select Market under the symbol “GBDC.” Our investment objective is to generate current income and capital appreciation by investing primarily in one stop (a loan that combines characteristics of traditional first lien senior secured loans and second lien or subordinated loans and that are often referred to by other middle-market lenders as unitranche loans) and other senior secured loans of U.S. middle-market companies. We also selectively invest in second lien and subordinated loans of, and warrants and minority equity securities in U.S. middle-market companies. We intend to achieve our investment objective by (1) accessing the established loan origination channels developed by Golub Capital, a leading lender to U.S. middle-market companies with over $90.0 billion in capital under management(1) as of April 1, 2026, (2) selecting investments within our core middle-market company focus, (3) partnering with experienced private equity firms, or sponsors, in many cases with whom Golub Capital has invested alongside in the past, (4) implementing the disciplined underwriting standards of Golub Capital and (5) drawing upon the aggregate experience and resources of Golub Capital. Our investment activities are managed by GC Advisors and supervised by our board of directors of which a majority of the members are independent of us, GC Advisors and its affiliates. Under an investment advisory agreement, or the Investment Advisory Agreement, we have agreed to pay GC Advisors an annual base management fee based on our average adjusted gross assets as well as an incentive fee based on our investment performance. The Investment Advisory Agreement was most recently approved by our board of directors in May 2026. Under an administrative agreement, or the Administration Agreement, we are provided with certain administrative services by an administrator, or the Administrator, which is currently Golub Capital LLC. Under the Administration Agreement, we have agreed to reimburse the Administrator for our allocable portion (subject to the review and approval of our independent directors) of overhead and other expenses incurred by the Administrator in performing its obligations under the Administration Agreement. We seek to create a portfolio that includes primarily one stop and other senior secured loans by primarily investing approximately $10.0 million to $85.0 million of capital, on average, in the securities of U.S. middle-market companies. We also selectively invest more than $85.0 million in some of our portfolio companies and generally expect that the size of our individual investments will vary proportionately with the size of our capital base. We generally invest in securities that have been rated below investment grade by independent rating agencies or that would be rated below investment grade if they were rated. These securities, which are often referred to as “junk,” have predominantly speculative characteristics with respect to the issuer’s capacity to pay interest and repay principal. In addition, many of our debt investments have floating interest rates that reset on a periodic basis and typically do not fully pay down principal prior to maturity, which could increase our risk of losing part or all of our investment. As of June 30, 2026 and September 30, 2025, our portfolio at fair value was comprised of the following: As of June 30, 2026 As of September 30, 2025 Investment Type Investments at Fair Value (In thousands) Percentage of Total Investments Investments at Fair Value (In thousands) Percentage of Total Investments Senior secured $ 391,132 4.8 % $ 442,477 5.0 % One stop 7,162,462 87.4 7,615,809 86.8 Second lien 22,877 0.3 26,409 0.3 Subordinated debt 36,171 0.4 38,412 0.5 Equity 583,711 7.1 646,282 7.4 Total $ 8,196,353 100.0 % $ 8,769,389 100.0 % (1) “Capital under management” is a gross measure of invested capital including leverage as of April 1, 2026. 150 TABLE OF CONTENTS One stop loans include loans to technology companies undergoing strong growth due to new services, increased adoption and/or entry into new markets. We refer to loans to these companies as recurring revenue loans. Other targeted characteristics of recurring revenue businesses include strong customer revenue retention rates, a diversified customer base and backing from growth equity or venture capital firms. In some cases, the borrower’s high revenue growth is supported by a high level of discretionary spending. As part of the underwriting of such loans and consistent with industry practice, we adjust our characterization of the earnings of such borrowers for a reduction or elimination of such discretionary expenses, if appropriate. As of June 30, 2026 and September 30, 2025, one stop loans included $627.5 million and $771.9 million, respectively, of recurring revenue loans at fair value. As of June 30, 2026 and September 30, 2025, we had debt and equity investments in 424 and 417 portfolio companies, respectively. 151 TABLE OF CONTENTS The following table shows the weighted average annualized income yield and weighted average annualized investment income yield of both our earning and total portfolio company investments, which represented nearly 100% of our debt investments, as well as the annualized total return based on (i) our average net asset value, (ii) our average net asset value per share, and (iii) the change in the quoted market price of our stock and assuming distributions were reinvested in accordance with our dividend reinvestment plan, or DRIP, in each case for the three months ended June 30, 2026 and March 31, 2026 and the nine months ended June 30, 2026 and June 30, 2025: For the three months ended For the nine months ended June 30, 2026 March 31, 2026 June 30, 2026 June 30, 2025 Weighted average income yield(1)* 9.4% 9.4% 9.5% 10.6% Weighted average investment income yield(2)* 9.9% 9.7% 9.8% 10.9% Weighted average income yield of total investments(3)* 8.8% 8.8% 8.8% 10.0% Weighted average investment income yield of total investments(4)* 9.2% 9.1% 9.2% 10.3% Total return based on average net asset value(5) 1.5% (1.2)% 2.0% 7.0% Annualized total return based on average net asset value(5)* 6.1% N/A 2.6% 9.3% Total return based on net asset value per share(6) 1.5% (1.3)% 2.0% 7.0% Annualized total return based on net asset value per share(6)* 6.2% N/A 2.7% 9.3% Total return based on market value(7) 4.3% (4.3)% 1.6% 5.1% *Annualized (1)Represents income from interest, fees, interest earned on cash, accrued PIK and non-cash dividend income, excluding amortization of capitalized fees, discounts and GCIC/GBDC 3 acquisition purchase premium (as described in Note 2 of the consolidated financial statements), divided by the daily average fair value of earning portfolio company investments, and does not represent a return to any investor in us. (2)Represents income from interest, fees, interest earned on cash, accrued PIK and non-cash dividend income and amortization of capitalized fees and discounts, excluding amortization of GCIC/GBDC 3 acquisition purchase premium (as described in Note 2 of the consolidated financial statements), divided by the daily average fair value of earning portfolio company investments, and does not represent a return to any investor in us. (3)Represents income from interest, fees, interest earned on cash, accrued PIK and non-cash dividend income, excluding amortization of capitalized fees, discounts and GCIC/GBDC 3 acquisition purchase premium (as described in Note 2 of the consolidated financial statements), divided by the daily average total fair value of portfolio company investments, and does not represent a return to any investor in us. (4)Represents income from interest, fees, interest earned on cash, accrued PIK and non-cash dividend income and amortization of capitalized fees and discounts, excluding amortization of GCIC/GBDC 3 acquisition purchase premium (as described in Note 2 of the consolidated financial statements), divided by the daily average total fair value of portfolio company investments, and does not represent a return to any investor in us. (5)Total return based on average net asset value is calculated as (a) the net increase/(decrease) in net assets resulting from operations divided by (b) the daily average of total net assets. Total return does not include sales load. (6)Total return based on net asset value per share is calculated as (a) net income per share for the period, (b) divided by net asset value per share as of the end of the period. Total return does not include sales load. (7)Total return based on market value assumes distributions are reinvested in accordance with the DRIP. Total return does not include sales load. Revenues: We generate revenue in the form of interest and fee income on debt investments and capital gains and distributions, if any, on portfolio company investments that we originate or acquire. Our debt investments, whether in the form of senior secured, one stop, second lien or subordinated loans, typically have a term of three to seven years and bear interest at a fixed or floating rate. In some instances, we receive payments on our debt investments based on scheduled amortization of the outstanding balances. In addition, we receive repayments of some of our debt investments prior to their scheduled maturity date. The frequency or volume of these repayments fluctuates significantly from period to period. Our portfolio activity also reflects the proceeds of sales of securities. In some cases, our investments provide for deferred interest payments or PIK interest. The principal amount of loans and any accrued but unpaid interest generally become due at the maturity date. 152 TABLE OF CONTENTS In addition, we generate revenue in the form of commitment, origination, amendment, structuring or due diligence fees, fees for providing managerial assistance, administrative agent fees and consulting fees. Loan origination fees, original issue discount and market discount or premium are capitalized, and we accrete or amortize such amounts as interest income. We record prepayment premiums on loans as fee income. For additional details on revenues, see “Critical Accounting Policies—Revenue Recognition.” We recognize realized gains or losses on investments based on the difference between the net proceeds from the disposition and the amortized cost basis of the investment or derivative instrument, without regard to unrealized gains or losses previously recognized. We record current period changes in fair value of investments and derivative instruments that are measured at fair value as a component of the “Net change in unrealized appreciation (depreciation) on investment transactions” in the Consolidated Statements of Operations. Expenses: Our primary operating expenses include the payment of fees to GC Advisors under the Investment Advisory Agreement and interest expense on our outstanding debt. We bear all other out-of-pocket costs and expenses of our operations and transactions, including: •calculating our net asset value, or NAV (including the cost and expenses of any independent valuation firm); •fees and expenses incurred by GC Advisors payable to third parties, including agents, consultants or other advisors, in monitoring financial and legal affairs for us and in monitoring our investments and performing due diligence on our prospective portfolio companies or otherwise relating to, or associated with, evaluating and making investments, which fees and expenses include, among other items, due diligence reports, appraisal reports, any studies commissioned by GC Advisors and travel and lodging expenses; •expenses related to unsuccessful portfolio acquisition efforts; •offerings of our common stock and other securities; •administration fees and expenses, if any, payable under the Administration Agreement (including payments based upon our allocable portion of the Administrator’s overhead in performing its obligations under the Administration Agreement, including rent and the allocable portion of the cost of our chief compliance officer, chief financial officer and their respective staffs); •fees payable to third parties, including agents, consultants or other advisors, relating to, or associated with, evaluating and making investments in portfolio companies, including costs associated with meeting financial sponsors; •transfer agent, dividend agent and custodial fees and expenses; •U.S. federal and state registration and franchise fees; •all costs of registration and listing our shares on any securities exchange; •U.S. federal, state and local taxes; •independent directors’ fees and expenses; •costs of preparing and filing reports or other documents required by the SEC or other regulators; •costs of any reports, proxy statements or other notices to stockholders, including printing costs; •costs associated with individual or group stockholders; •costs associated with compliance under the Sarbanes-Oxley Act of 2002, as amended, or the Sarbanes-Oxley Act; •our allocable portion of any fidelity bond, directors and officers/errors and omissions liability insurance, and any other insurance premiums; •direct costs and expenses of administration, including printing, mailing, long distance telephone, copying, secretarial and other staff, independent auditors and outside legal costs; •proxy voting expenses; and •all other expenses incurred by us or the Administrator in connection with administering our business. We expect our general and administrative expenses to be relatively stable or decline as a percentage of total assets during periods of asset growth and to increase during periods of asset declines. Prior to the redemption of the 2018 Notes and termination of the documents governing the 2018 Debt Securitization on November 18, 2024, GC Advisors served as collateral manager for the 2018 Issuer under a collateral management agreement, or the 2018 Collateral Management Agreement, and was entitled to receive an annual fee in an amount equal to 0.35% of the principal balance of the portfolio loans held by the 2018 Issuer at the beginning of 153 TABLE OF CONTENTS the collection period relating to each payment date, which was payable in arrears on each payment date. Under the 2018 Collateral Management Agreement, the term “collection period” referred to the period commencing on the third business day prior to the preceding payment date and ending on (but excluding) the third business day prior to such payment date. Prior to the redemption of the GCIC 2018 Notes and the termination of the documents governing the GCIC 2018 Debt Securitization, GC Advisors served as collateral manager for Golub Capital Investment Corporation CLO II LLC, or the GCIC 2018 Issuer, under a collateral management agreement, or the GCIC 2018 Collateral Management Agreement, and was entitled to receive an annual fee in an amount equal to 0.35% of the principal balance of the portfolio loans held by the GCIC 2018 Issuer at the beginning of the collection period relating to each payment date, which was payable in arrears on each payment date. Under the 2018 GCIC Collateral Management Agreement, the term “collection period” generally referred to a quarterly period commencing on the day after the end of the prior collection period to the tenth business day prior to the payment date. Prior to the redemption of the GBDC 3 2021 Notes and the termination of the documents governing the GBDC 3 2021 Debt Securitization, GC Advisors served as collateral manager for our indirect, wholly owned, consolidated subsidiary, Golub Capital BDC 3 CLO 1 LLC, or the GBDC 3 2021 Issuer, under a collateral management agreement, or the GBDC 3 2021 Collateral Management Agreement, and was entitled to receive an annual fee in an amount equal to 0.35% of the principal balance of the portfolio loans held by the GBDC 3 2021 Issuer at the beginning of the collection period relating to each payment date, which was payable in arrears on each payment date. Under the GBDC 3 2021 Collateral Management Agreement, the term “collection period” referred to the period commencing on the tenth business day prior to the preceding payment date and ending on (but excluding) the tenth business day prior to such payment date. Prior to the redemption of the GBDC 3 2022-2 Notes and the termination of the documents governing the GBDC 3 2022-2 Debt Securitization, GC Advisors served as collateral manager for our indirect, wholly owned, consolidated subsidiary, Golub Capital BDC 3 CLO 2 LLC, or the GBDC 3 2022-2 Issuer, under a collateral management agreement, or the GBDC 3 2022-2 Collateral Management Agreement, and was entitled to receive an annual fee in an amount equal to 0.35% of the principal balance of the portfolio loans held by the GBDC 3 2022-2 Issuer at the beginning of the collection period relating to each payment date, which is payable in arrears on each payment date. Under the GBDC 3 2022-2 Collateral Management Agreement, the term “collection period” referred to the period commencing on the tenth business day prior to the preceding payment date and ending on (but excluding) the tenth business day prior to such payment date. Prior to the redemption of the GBDC 3 2022 Notes and the termination of the documents governing the GBDC 3 2022 Debt Securitization, GC Advisors served as collateral manager for our indirect, wholly owned, consolidated subsidiary, Golub Capital BDC 3 ABS 2022-1 LLC, or the GBDC 3 2022 Issuer, under a collateral management agreement, or the GBDC 3 2022 Collateral Management Agreement, and was entitled to receive an annual fee in an amount equal to 0.35% of the principal balance of the portfolio loans held by the GBDC 3 2022 Issuer at the beginning of the collection period relating to each payment date, which is payable in arrears on each payment date. Under the GBDC 3 2022 Collateral Management Agreement, the term “collection period” relating to any payment date, referred to the period commencing on the tenth business day prior to the preceding payment date and ending on (but excluding) the tenth business day prior to such payment date. GC Advisors, as collateral manager for our indirect, wholly owned, consolidated subsidiary, Golub Capital BDC CLO 8 LLC, or the 2024 Issuer, under a collateral management agreement, or the 2024 Issuer Collateral Management Agreement, is entitled to receive an annual fee in an amount equal to 0.35% of the principal balance of the portfolio loans held by the 2024 Issuer at the beginning of the collection period relating to each payment date, which is payable in arrears on each payment date. Under the 2024 Issuer Collateral Management Agreement, the term “collection period” refers to the period commencing on the third business day prior to the preceding payment date and ending on (but excluding) the third business day prior to such payment date. Collateral management fees are paid directly by the 2018 Issuer, GCIC 2018 Issuer, GBDC 3 2021 Issuer, GBDC 3 2022 Issuer, GBDC 3 2022-2 Issuer and the 2024 Issuer and are offset against the management fees payable under the Investment Advisory Agreement. These fees include structuring and placement fees paid by the 2018 Issuer to Morgan Stanley & Co. LLC for its services in connection with the structuring of the 2018 Debt Securitization and by the 2024 Issuer to Deutsche Bank Securities Inc. for its services in connection with the structuring of the 2024 Debt Securitization. Before we acquired the GCIC 2018 Issuer as part of the GCIC Merger, the GCIC 2018 Issuer paid Wells Fargo Securities, LLC structuring and placement fees for its services in connection with the initial structuring 154 TABLE OF CONTENTS of the GCIC 2018 Debt Securitization. Before we acquired the GBDC 3 2021 Issuer as a part of the GBDC 3 Merger, the GBDC 3 2021 Issuer paid Deutsche Bank AG, New York Branch, structuring and placement fees for its services in connection with the structuring of each of the GBDC 3 2021 Debt Securitization and the GBDC 3 2022 Debt Securitization (as defined in Note 7 of our consolidated financial statements). Before we acquired the GBDC 3 2022-2 Issuer as a part of the GBDC 3 Merger, the GBDC 3 2022-2 Issuer paid GreensLedge Capital Markets LLC and KeyBanc Capital Markets Inc. structuring and placement fees for its services in connection with the structuring of the GBDC 3 2022-2 Debt Securitization (as defined in Note 7 of our consolidated financial statements).Term debt securitizations are also known as CLOs, and are a form of secured financing incurred by us, which are consolidated by us and subject to our overall asset coverage requirement. The 2018 Issuer, GCIC 2018 Issuer, GBDC 3 2021 Issuer, GBDC 3 2022 Issuer, GBDC 3 2022-2 Issuer and the 2024 Issuer also agreed to pay ongoing administrative expenses to the trustee, collateral manager, independent accountants, legal counsel, rating agencies and independent managers in connection with developing and maintaining reports, and providing required services in connection with the administration of the 2018 Debt Securitization, GCIC 2018 Debt Securitization, the GBDC 3 2021 Debt Securitization, the GBDC 3 2022 Debt Securitization, the GBDC 3 2022-2 Debt Securitization and the 2024 Debt Securitization and collectively the Debt Securitizations, as applicable. We believe that these administrative expenses approximate the amount of ongoing fees and expenses that we would be required to pay in connection with a traditional secured credit facility. Our common stockholders indirectly bear all of these expenses. 155 TABLE OF CONTENTS Recent Developments On July 2, 2026, we amended our revolving credit facility with JPMorgan to, among other things, (i) remove the 0.10% adjustment to term SOFR rate and (ii) extend the maturity date to July 2, 2031 from April 4, 2030. On July 31, 2026, our Board declared a quarterly distribution of $0.33 per share, which is payable on September 29, 2026 to holders of record as of September 14, 2026. For the period of July 1, 2026 through August 3, 2026, Wells Fargo Securities, LLC, as broker, has repurchased 382,300 shares of our common stock pursuant to the Program (as defined in Note 2 of our consolidated financial statements) for an aggregate purchase price of approximately $4.9 million at an average price of $12.86 per share. 156 TABLE OF CONTENTS Consolidated Results of Operations In addition to our analysis of the year-to-date reporting period compared to the year-to-date prior periods, we are presenting our analysis for the reporting quarter compared to the immediately preceding quarter as we believe this comparison will provide a more meaningful analysis of our business as our results are largely driven by market changes, not seasonal business activity. Consolidated operating results for the three months ended June 30, 2026 and March 31, 2026 and the nine months ended June 30, 2026 and June 30, 2025 are as follows: Three months ended Variances Nine months ended Variances June 30, 2026 March 31, 2026 June 30, 2026 vs. March 31, 2026 June 30, 2026 June 30, 2025 2026 vs.2025 (In thousands) Interest income $ 160,302 $ 160,656 $ (354) $ 501,338 $ 581,119 $ (79,781) Payment-in-kind interest income 16,351 17,132 (781) 48,002 38,577 9,425 Discount amortization 8,348 5,740 2,608 20,632 19,404 1,228 GCIC/GBDC 3 acquisition purchase premium amortization (2,256) (2,520) 264 (7,944) (13,880) 5,936 Non-cash dividend income 4,232 6,158 (1,926) 17,424 23,091 (5,667) Dividend income 1 202 (201) 788 1,497 (709) Fee income 752 766 (14) 2,631 3,128 (497) Total investment income 187,730 188,134 (404) 582,871 652,936 (70,065) Total expenses 102,513 102,587 (74) 316,349 356,897 (40,548) Net investment income before taxes 85,217 85,547 (330) 266,522 296,039 (29,517) Income and excise taxes — — — — (475) 475 Net investment income after taxes 85,217 85,547 (330) 266,522 296,514 (29,992) Net realized gain (loss) on investment transactions excluding GCIC/GBDC 3 acquisition purchase premium (24,551) (10,345) (14,206) (38,685) (38,486) (199) Net realized gain (loss) on investment transactions due to GCIC/GBDC 3 acquisition purchase premium (230) (10) (220) (289) (434) 145 Net change in unrealized appreciation (depreciation) on investment transactions excluding GCIC/GBDC 3 acquisition purchase premium (5,911) (124,518) 118,607 (160,320) 8,087 (168,407) Net change in unrealized appreciation (depreciation) on investment transactions due to GCIC/GBDC 3 acquisition purchase premium 2,486 2,530 (44) 8,233 14,314 (6,081) Net gain (loss) on investment transactions (28,206) (132,343) 104,137 (191,061) (16,519) (174,542) Net realized gain (loss) on extinguishment of debt — — — — (48) 48 (Provision) benefit for taxes on unrealized appreciation on investments (2) — (2) (2) 409 (411) Net increase (decrease) in net assets resulting from operations $ 57,009 $ (46,796) $ 103,805 $ 75,459 $ 280,356 $ (204,897) Average earning debt investments, at fair value $ 7,591,013 $ 7,785,504 $ (194,491) $ 7,826,579 $ 7,928,153 $ (101,574) Average earning preferred equity investments, at fair value $ 139,338 $ 202,793 $ (63,455) $ 185,314 $ 245,864 $ (60,550) Net income can vary substantially from period to period for various reasons, including the recognition of realized gains and losses and unrealized appreciation and depreciation. As a result, comparisons of operating results may not be meaningful. On September 16, 2019, and June 3, 2024, we completed our acquisitions of GCIC and GBDC 3, respectively. Each acquisition was accounted for under the asset acquisition method of accounting in accordance with Accounting Standards Codification, or ASC, 805-50, Business Combinations — Related Issues. Under asset acquisition accounting, where the consideration paid to GCIC and GBDC 3’s stockholders exceeded the relative fair values of the assets acquired and liabilities assumed, the premium paid by us was allocated to the cost of the GCIC and GBDC 3 investments acquired by us pro-rata based on their relative fair value. Immediately following each acquisition of GCIC and GBDC 3, we recorded its assets at their respective fair values and, as a result, the purchase premium allocated to the cost basis of the GCIC and GBDC 3 assets acquired was immediately recognized as unrealized depreciation on our Consolidated Statement of Operations. The purchase premium allocated to investments in loan securities will amortize over the life of the loans through interest income with a corresponding reversal of the unrealized depreciation on such loans acquired through their ultimate disposition. The purchase premium allocated 157 TABLE OF CONTENTS to investments in equity securities will not amortize over the life of the equity securities through interest income and, assuming no subsequent change to the fair value of the equity securities acquired from GCIC and GBDC 3 and disposition of such equity securities at fair value, we will recognize a realized loss with a corresponding reversal of the unrealized depreciation upon disposition of the equity securities acquired. As a supplement to our GAAP financial measures, we have provided the following non-GAAP financial measures that we believe are useful for the reasons described below: •“Adjusted Net Investment Income” - excludes the amortization of the purchase price premium from net investment income calculated in accordance with GAAP; •“Adjusted Net Investment Income Before Accrual for Capital Gain Incentive Fee” - Adjusted Net Investment Income excluding the accrual or reversal for the capital gain incentive fee under GAAP; •“Adjusted Net Realized and Unrealized Gain/(Loss)” - excludes the unrealized loss resulting from the purchase premium write-down and the corresponding reversal of the unrealized loss resulting from the amortization of the premium on loans or from the sale of equity investments from the determination of realized and unrealized gain/(loss) determined in accordance with GAAP; and •“Adjusted Net Income” – calculates net income and earnings per share based on Adjusted Net Investment Income and Adjusted Net Realized and Unrealized Gain/(Loss). Three months ended Nine months ended June 30, 2026 March 31, 2026 June 30, 2026 June 30, 2025 (In thousands) Net investment income after taxes $ 85,217 $ 85,547 $ 266,522 $ 296,514 Add: GCIC/GBDC 3 acquisition purchase premium amortization 2,256 2,520 7,944 13,880 Adjusted Net Investment Income $ 87,473 $ 88,067 $ 274,466 $ 310,394 Net gain (loss) on investment transactions $ (28,206) $ (132,343) $ (191,061) $ (16,519) Add: Realized loss on investment transactions due to GCIC/GBDC 3 acquisition purchase premium 230 10 289 434 Less: Net change in unrealized appreciation on investment transactions due to GCIC/GBDC 3 acquisition purchase premium (2,486) (2,530) (8,233) (14,314) Adjusted Net Realized and Unrealized Gain/(Loss) $ (30,462) $ (134,863) $ (199,005) $ (30,399) Net increase (decrease) in net assets resulting from operations $ 57,009 $ (46,796) $ 75,459 $ 280,356 Add: GCIC/GBDC 3 acquisition purchase premium amortization 2,256 2,520 7,944 13,880 Add: Realized loss on investment transactions due to GCIC/GBDC 3 acquisition purchase premium 230 10 289 434 Less: Net change in unrealized appreciation on investment transactions due to GCIC/GBDC 3 acquisition purchase premium (2,486) (2,530) (8,233) (14,314) Adjusted Net Income $ 57,009 $ (46,796) $ 75,459 $ 280,356 We believe that excluding the financial impact of the GCIC/GBDC 3 acquisition purchase premium in the above non-GAAP financial measures is useful for investors as this is a non-cash expense/loss and is one method we use to measure our results of operations. In addition, we believe that providing the Adjusted Net Investment Income Before Accrual for Capital Gain Incentive Fee is a useful non-GAAP financial measure as such accrual is not contractually payable under the terms of the Investment Advisory Agreement. Although these non-GAAP financial measures are intended to enhance investors’ understanding of our business and performance, these non-GAAP financial measures should not be considered an alternative to GAAP. 158 TABLE OF CONTENTS Investment Income Investment income remained relatively stable decreasing just $0.4 million from the three months ended March 31, 2026 to the three months ended June 30, 2026 as a $2.6 million increase in discount amortization driven by accelerated amortization recognized on loan repayments was offset by (1) a decrease in interest income as a result of a decrease in the average earning debt investments balance of $194.5 million and (2) a decrease in dividend income due to preferred equity investments taken to non-accrual during the quarter. Investment income decreased from the nine months ended June 30, 2025 to the nine months ended June 30, 2026 by $70.1 million, primarily due to (1) a decrease in interest income as a result of declining interest base rates and, to a lesser extent, spread compression on new and amended debt investments and (2) a decrease in the average earning debt investments balance of $101.6 million. For the three and nine months ended June 30, 2026, PIK interest income represented 8.6% and 8.1%, respectively, of total investment income excluding amortization of purchase premium for the GCIC/GBDC 3 acquisitions. For the three and nine months ended June 30, 2025, PIK interest income represented 6.1% and 5.8%, respectively, of total investment income excluding amortization of purchase premium for the GCIC/GBDC 3 acquisitions. The annualized income yield by debt security type for the three months ended June 30, 2026 and March 31, 2026 and the nine months ended June 30, 2026 and June 30, 2025 are as follows: Three months ended Nine months ended June 30, 2026 March 31, 2026 June 30, 2026 June 30, 2025 Senior secured 9.3% 9.0% 9.2% 10.2% One stop 9.3% 9.2% 9.4% 10.4% Second lien 13.2% 13.1% 13.2% 13.5% Subordinated debt 13.4% 13.4% 13.3% 13.8% Income yields on senior secured loans increased for the three months ended June 30, 2026 as compared to the three months ended March 31, 2026 primarily due to spread adjustments resulting from certain debt investment amendments while income yields on one stop loans remained relatively stable for the three months ended June 30, 2026 as compared to the three months ended March 31, 2026. Income yields on senior secured and one stop loans decreased for the nine months ended June 30, 2026 as compared to the nine months ended June 30, 2025, primarily due to declining interest base rates and, to a lesser extent, spread compression on new and amended debt investments. Our loan portfolio is partially insulated from a drop in floating interest rates, as 98.0% of the loan portfolio at fair value is subject to an interest rate floor. As of June 30, 2026 and September 30, 2025, the weighted average base rate floor of our loans was 0.76% and 0.78%, respectively. As of June 30, 2026, we have second lien investments in three portfolio companies and subordinated debt investments in seven portfolio companies as shown in the Consolidated Schedule of Investments. Due to the limited number of second lien and subordinated debt investments, income yields on second lien and subordinated debt investments can be significantly impacted by the addition, subtraction or refinancing of one investment. For additional details on investment yields and asset mix, refer to the “Liquidity and Capital Resources - Portfolio Composition, Investment Activity and Yield” section below. 159 TABLE OF CONTENTS Expenses The following table summarizes our expenses for the three months ended June 30, 2026 and March 31, 2026 and the nine months ended June 30, 2026 and June 30, 2025: Three months ended Variances Nine months ended Variances June 30, 2026 March 31, 2026 June 30, 2026 vs. March 31, 2026 June 30, 2026 June 30, 2025 2026 vs. 2025 (In thousands) Interest and other debt financing expenses $ 58,269 $ 58,497 $ (228) $ 180,473 $ 212,716 $ (32,243) Amortization of debt issuance costs 2,724 2,572 152 7,903 7,537 366 Base management fee 20,716 21,035 (319) 63,866 65,376 (1,510) Income Incentive fee 15,436 15,542 (106) 48,435 54,848 (6,413) Administrative service fee 3,107 2,939 168 9,226 9,229 (3) Professional fees 1,889 1,627 262 5,301 5,747 (446) General and administrative expenses 372 375 (3) 1,145 1,444 (299) Total expenses $ 102,513 $ 102,587 $ (74) $ 316,349 $ 356,897 $ (40,548) Average debt outstanding $ 4,654,965 $ 4,747,270 $ (92,305) $ 4,763,136 $ 4,867,651 $ (104,515) Interest Expense Interest and other debt financing expenses, net of amortization of debt issuance costs, decreased from the three months ended March 31, 2026 to the three months ended June 30, 2026 by $0.1 million, primarily due to a decrease in interest expense as a result of a decrease in the average debt outstanding of $92.3 million. Interest and other debt financing expenses, including amortization of debt issuance costs, decreased from the nine months ended June 30, 2025 to the nine months ended June 30, 2026 by $31.9 million, primarily due to reduced borrowing costs resulting from (i) the debt capital refinancings completed during the fiscal year 2025 first quarter, including the 2024 Debt Securitization issuance of $1.3 billion in notes which bear interest at a weighted-average rate of three-month SOFR + 1.58%, (ii) the April 2025 amendment to the JPM Credit Facility that reduced the applicable margin to a range of 1.525% to 1.775% from a range of 1.75% to 1.875% and (iii) decreasing interest base rates on our floating rate borrowings. For more information about our outstanding borrowings for the three and nine months ended June 30, 2026 and 2025, including the terms thereof, see Note 7 in the notes to our consolidated financial statements and the “Liquidity and Capital Resources” section below. For the three months ended June 30, 2026 and March 31, 2026, the effective annualized average interest rate1 on our total debt was 5.3% and 5.2%, respectively. For the nine months ended June 30, 2026 and 2025, the effective annualized average interest rate1 on our total debt was 5.3% and 5.9%, respectively. The effective annualized average interest rate1 increased for the three months ended June 30, 2026 compared to the three months ended March 31, 2026 due to the issuance of the 2031 Notes in May 2026. The effective annualized average interest rate1 decreased for the nine months ended June 30, 2026 compared to the nine months ended June 30, 2025 primarily due to reduced borrowing costs resulting from (1) the debt capital refinancing completed during fiscal year 2025, (2) the April 2025 amendment to the JPM Credit Facility that reduced the applicable margin and (3) decreasing interest base rates on our floating rate borrowings. Management Fee The base management fee decreased from the three months ended March 31, 2026 to the three months ended June 30, 2026 primarily due to a decrease in average adjusted gross assets from the three months ended March 31, 2026 to the three months ended June 30, 2026. The base management fee decreased from the nine months ended June 30, 2025 to the nine months ended June 30, 2026 primarily due to a decrease in average adjusted gross assets from the nine months ended June 30, 2025 to the nine months ended June 30, 2026. Incentive Fees 1 The effective average interest rate includes amortization of debt financing costs, amortization of discounts on notes issued and non-usage facility fees and the net contractual interest rate swap expense on the 2028, 2029 and 2031 Notes but excluding the net unrealized gain/(loss) related to the fair value hedges associated with the 2028, 2029 and 2031 Notes interest rate swaps. 160 TABLE OF CONTENTS The incentive fee payable under the Investment Advisory Agreement consists of two parts: (1) the income component, or the Income Incentive Fee, and (2) the capital gains component, or the Capital Gain Incentive Fee. The Income Incentive Fee decreased by $0.1 million from the three months ended March 31, 2026 to the three months ended June 30, 2026 primarily due to a decrease in Pre-Incentive Fee Net Investment Income. The Income Incentive Fee decreased by $6.4 million from the nine months ended June 30, 2025 to the nine months ended June 30, 2026 primarily due to a decrease in Pre-Incentive Fee Net Investment Income and a lower rate of return on the value of our net assets driven by a decrease in the investment income yield on our investment portfolio due to declining interest base rates and a decrease in our average earning debt investments. For each of the three months ended June 30, 2026 and March 31, 2026 and the nine months ended June 30, 2026 and June 30, 2025, we were fully through the Income Incentive Fee “catch-up” provision and the Income Incentive Fee was equal to 15% of Pre-Incentive Fee Net Investment Income. As of June 30, 2026 and September 30, 2025, there was no Capital Gain Incentive Fee payable as calculated under the Investment Advisory Agreement. In accordance with GAAP, we are required to include the aggregate unrealized capital appreciation on investments in the calculation and accrue a capital gain incentive fee as if such unrealized capital appreciation were realized, even though such unrealized capital appreciation is not permitted to be considered in calculating the fee actually payable under the Investment Advisory Agreement. As of June 30, 2026 and September 30, 2025, there was no capital gain incentive fee accrual calculated in accordance with GAAP. Any payment due under the terms of the Investment Advisory Agreement is calculated in arrears at the end of each calendar year. No Capital Gain Incentive Fees as calculated under the Investment Advisory Agreement or any prior investment advisory agreements, as applicable, have been payable since December 31, 2018. For additional details on unrealized appreciation and depreciation of investments, refer to the “Net Realized and Unrealized Gains and Losses” section below. Professional Fees, Administrative Service Fee and General and Administrative Expenses In total, the administrative service fee, professional fees and general and administrative expenses increased by $0.4 million from the three months ended March 31, 2026 to the three months ended June 30, 2026, primarily due to increases in the administrative service fee and professional fees that were partially offset by a decrease in general and administrative expenses. In total, professional fees, the administrative service fee and general and administrative expenses decreased by $0.7 million from the nine months ended June 30, 2025 to the nine months ended June 30, 2026, primarily due to decreases across each of these expense categories. The Administrator pays for certain expenses incurred by us. These expenses are subsequently reimbursed in cash. Total expenses reimbursed to the Administrator during the three months ended June 30, 2026 and March 31, 2026 and the nine months ended June 30, 2026 and June 30, 2025 were $1.1 million, $2.6 million, $6.2 million, and $6.3 million, respectively. As of June 30, 2026 and September 30, 2025, included in accounts payable and other liabilities were $2.7 million and $2.5 million, respectively, of expenses paid on behalf of us by the Administrator. Net Realized and Unrealized Gains and Losses The following table summarizes our net realized and unrealized gains (losses) for the three months ended June 30, 2026 and March 31, 2026 and the nine months ended June 30, 2026 and June 30, 2025: 161 TABLE OF CONTENTS Three months ended Variances Nine months ended Variances June 30, 2026 March 31, 2026 June 30, 2026 vs. March 31, 2026 June 30, 2026 June 30, 2025 2026 vs. 2025 (in thousands) (In thousands) Net realized gain (loss) from investments $ (10,841) $ (1,441) $ (9,400) $ (14,951) $ (41,410) $ 26,459 Net realized gain (loss) from investments due to GCIC/GBDC 3 acquisition purchase premium (230) (10) (220) (289) (434) 145 Net realized gain (loss) from foreign currency transactions (13,710) 1,354 (15,064) (13,476) (4,279) (9,197) Net realized gain (loss) from forward currency contracts — (10,258) 10,258 (10,258) 7,203 (17,461) Net realized gain (loss) on investment transactions $ (24,781) $ (10,355) $ (14,426) $ (38,974) $ (38,920) $ (54) Unrealized appreciation from investments $ 47,603 $ 11,111 $ 36,492 $ 33,957 $ 111,587 $ (77,630) Unrealized (depreciation) from investments (63,636) (145,273) 81,637 (216,383) (100,024) (116,359) Unrealized appreciation (depreciation) from investments due to GCIC/GBDC 3 acquisition purchase premium 2,486 2,530 (44) 8,233 14,314 (6,081) Unrealized appreciation (depreciation) from forward currency contracts 6,951 14,042 (7,091) 21,285 (15,787) 37,072 Unrealized appreciation (depreciation) on foreign currency translation 3,171 (4,398) 7,569 821 12,311 (11,490) Net change in unrealized appreciation (depreciation) on investment transactions $ (3,425) $ (121,988) $ 118,563 $ (152,087) $ 22,401 $ (174,488) Net realized gain (loss) on extinguishment of debt $ — $ — — $ — $ (48) $ 48 During the three months ended June 30, 2026, we had a net realized loss of $24.8 million, primarily attributable to (i) $13.7 million of net realized losses recognized on the translation of foreign currency amounts and transactions into U.S. dollars, which were partially offset by $10.1 million of unrealized appreciation and the reversal of unrealized depreciation previously recognized and (ii) realized losses recognized on the restructuring of two portfolio company investments that was partially offset by (iii) $3.4 million of net realized gains recognized on the disposition of equity investments in multiple portfolio companies. During the three months ended March 31, 2026, we had a net realized loss of $10.4 million, primarily attributable to (i) $8.9 million of net realized losses recognized on the settlement of forward currency contracts and translation of foreign currency amounts and transactions into U.S. dollars and (ii) realized losses recognized on the restructuring of a portfolio company investment. During the nine months ended June 30, 2026, we had a net realized loss of $39.0 million, primarily attributable to (i) $23.7 million of net realized losses recognized on the settlement of forward currency contracts and translation of foreign currency amounts and transactions into U.S. dollars, which were partially offset by $22.1 million of unrealized appreciation and the reversal of unrealized depreciation previously recognized, (ii) realized losses recognized on the restructuring of multiple portfolio company investments that were partially offset by (iii) $6.2 million of net realized gains recognized on the disposition of equity investments in multiple portfolio companies. During the nine months ended June 30, 2025, we had a net realized loss of $38.9 million, primarily attributable to realized losses recognized on the restructuring of debt and equity investments of multiple portfolio company investments and the sale of a portfolio company debt investment that was partially offset by net realized gains recognized on the disposition of three equity investments and the settlement of forward currency contracts and translation of foreign currency amounts and transactions into U.S. dollars. For the three months ended June 30, 2026, we had $47.6 million in unrealized appreciation on 254 portfolio company investments, which was offset by $63.6 million in unrealized depreciation on 202 portfolio company investments. For the three months ended March 31, 2026, we had $11.1 million in unrealized appreciation on 103 portfolio company investments, which was offset by $145.3 million in unrealized depreciation on 343 portfolio company investments. For the nine months ended June 30, 2026, we had $34.0 million in unrealized appreciation on 102 portfolio company investments, which was offset by $216.4 million in unrealized depreciation on 354 portfolio company investments. For the nine months ended June 30, 2025, we had $111.6 million in unrealized appreciation on 218 portfolio company investments, which was offset by $100.0 million in unrealized depreciation on 213 portfolio company investments. Unrealized appreciation for the three months ended June 30, 2026 was primarily due to the reversal of previously recognized unrealized depreciation related to (i) fair value adjustments related to market wide credit spread widening recognized during the quarter ended March 31, 2026 and (ii) portfolio company investments restructured during the period. Unrealized appreciation for the three months ended March 31, 2026 was primarily due to increases in the fair values of certain equity investments and the reversal of previously recognized unrealized depreciation on the restructuring of a portfolio company investment. Unrealized appreciation for the nine months ended June 30, 2026 was primarily due to increases in the fair values of certain equity investments and the reversal of previously recognized unrealized depreciation on the restructuring of a portfolio company investments. Unrealized appreciation for the nine months ended June 30, 2025 was primarily due to (i) the reversal of previously recognized unrealized 162 TABLE OF CONTENTS depreciation on the restructuring of portfolio company investments and (ii) fair valuing recent originations up to or near par. Unrealized depreciation for the three months ended June 30, 2026, primarily resulted from isolated deterioration in the performance of (i) debt and equity investments in portfolio companies that were moved to or on non-accrual status, (ii) debt and equity investments in certain portfolio companies with pre-existing credit challenges and (iii) debt and equity investments in a small number of portfolio companies negatively impacted by the macroeconomic environment. Unrealized depreciation for the three months ended March 31, 2026 primarily resulted from (1) fair value adjustments across our portfolio company investments related to market wide credit spread widening during the three months ended March 31, 2026, primarily on our well-performing loans rated in our highest internal performance rating 4 and 5 categories, as defined below under the “Portfolio Composition, Investment Activity and Yield” section and (2) isolated deterioration in the performance of (i) debt and equity investments in portfolio companies that were moved to or on non-accrual status and (ii) debt and equity investments in certain portfolio companies with pre-existing credit challenges. Unrealized depreciation for the nine months ended June 30, 2026, primarily resulted from (1) fair value adjustments across our portfolio company investments related to market wide credit spread widening during the three months ended March 31, 2026, primarily on our well-performing loans rated in our highest internal performance rating 4 and 5 categories and (2) isolated deterioration in the performance of (i) debt and equity investments in portfolio companies that were moved to or on non-accrual status, (ii) debt and equity investments in certain portfolio companies with pre-existing credit challenges and (iii) debt and equity investments in a small number of portfolio companies negatively impacted by the macroeconomic environment. Unrealized depreciation for the nine months ended June 30, 2025 primarily resulted from isolated deterioration in credit performance in (i) a small number of portfolio companies and (ii) portfolio companies that were moved to or on non-accrual status. For the nine months ended June 30, 2025, we had a realized loss on extinguishment of debt of less than $0.1 million, which represents the unamortized discount on the GBDC 3 2021 Notes assumed as a result on the GBDC 3 Merger, at termination. 163 TABLE OF CONTENTS Liquidity and Capital Resources For the nine months ended June 30, 2026, we experienced a net decrease in cash, cash equivalents, foreign currencies, restricted cash, restricted cash equivalents and restricted foreign currencies of $40.4 million. During the period, cash provided by operating activities was $653.5 million, primarily as a result of proceeds from principal payments and sales of portfolio investments of $829.0 million, partially offset by fundings of portfolio investments of $367.3 million, and net investment income after tax of $266.5 million. Lastly, cash used in financing activities was $694.0 million, primarily driven by repayments of debt of $1,351.8 million, distributions paid and purchases of common stock under the DRIP totaling $275.1 million, and purchases of common stock under our share repurchase program, or the Program, of $78.1 million, partially offset by borrowings on debt of $1,017.1 million. For the nine months ended June 30, 2025, we experienced a net decrease in cash, cash equivalents, foreign currencies, restricted cash, restricted cash equivalents and restricted foreign currencies of $179.0 million. During the period, cash used in operating activities was $379.7 million, primarily driven by proceeds from principal payments and sales of portfolio investments of $1,146.0 million and net investment income after tax of $296.5 million, offset by fundings of portfolio investments of $1,781.5 million. Lastly, cash provided by financing activities was $200.7 million, primarily driven by borrowings on debt of $3,517.9 million and net proceeds from the issuance of common stock through the ATM Program (as defined in Note 11 of our consolidated financial statements) of $37.4 million, offset by repayments of debt of $3,008.6 million, distributions paid of $281.0 million, purchases of common stock under the Program of $35.5 million and purchases of common stock under the DRIP of $20.6 million. As of June 30, 2026 and September 30, 2025, we had cash and cash equivalents totaling $13.0 million and $11.9 million, respectively. In addition, we had foreign currencies of $7.0 million and $11.7 million as of June 30, 2026 and September 30, 2025, respectively and restricted cash and restricted cash equivalents totaling $50.7 million and $88.8 million as of June 30, 2026 and September 30, 2025, respectively. We had no restricted foreign currencies as of June 30, 2026 and September 30, 2025. Cash, cash equivalents and foreign currencies are available to fund new investments, pay operating expenses and pay distributions. Restricted cash, restricted cash equivalents and restricted foreign currencies can be used to pay principal and interest on borrowings and to fund new investments that meet the guidelines under our debt securitizations or credit facilities, as applicable. As of June 30, 2026 and September 30, 2025, we did not have any debt securitizations that were past their reinvestment period term. Revolving Debt Facilities JPM Credit Facility - On February 11, 2021, we initially entered into the JPM Credit Facility (as defined in Note 7 of our consolidated financial statements), which, as of June 30, 2026, allowed us to borrow up to $2.0 billion at any one time outstanding, subject to leverage and borrowing base restrictions. As of June 30, 2026 and September 30, 2025, we had outstanding debt under the JPM Credit Facility of $271.6 million and $1,098.4 million, respectively. As of June 30, 2026 and September 30, 2025, subject to leverage and borrowing base restrictions, we had $1,725.9 million and $899.1 million, respectively, of remaining commitments and availability on the JPM Credit Facility. Adviser Revolver - On June 22, 2016, we entered into the Adviser Revolver (as defined in Note 7 of our consolidated financial statements), which, as amended, permitted us to borrow up to $300.0 million at any one time outstanding as of June 30, 2026. We entered into the Adviser Revolver in order to have the ability to borrow funds on a short-term basis and have in the past repaid, and generally intend in the future to repay, borrowings under the Adviser Revolver within 30 to 45 days from which they are drawn. As of June 30, 2026 and September 30, 2025, we had outstanding debt under the Adviser Revolver of $33.2 million and $39.2 million, respectively. GBDC 3 DB Credit Facility - Effective June 3, 2024, we assumed, as a result of the GBDC 3 Merger (as defined in Note 7 of our consolidated financial statements), the GBDC 3 DB Credit Facility (as defined in Note 7 of our consolidated financial statements). On November 19, 2024, all amounts outstanding under the GBDC 3 DB Credit Facility were repaid, following which the agreements governing the GBDC 3 DB Credit Facility were terminated. As of June 30, 2026 and September 30, 2025, we had no outstanding debt under the GBDC 3 DB Credit Facility. Debt Securitizations 2024 Debt Securitization - On November 18, 2024, we completed the 2024 Debt Securitization (the “2024 Debt Securitization”). The Class A-1R 2024 Notes and Class A-2RR 2024 Notes (each as defined in Note 7 of our consolidated financial statements) are included in the June 30, 2026 Consolidated Statements of Financial Condition 164 TABLE OF CONTENTS as our debt, and the Class B-R, Class C-R and Subordinated Notes were eliminated in consolidation. As of both June 30, 2026 and September 30, 2025, we had outstanding debt under the 2024 Debt Securitization of $1,364.0 million. GBDC 3 2022 Debt Securitization - Effective June 3, 2024, we assumed as a result of the GBDC 3 Merger, the GBDC 3 2022 Debt Securitization. On August 1, 2025, the GBDC 3 2022 Notes (as defined in Note 7 of our consolidated financial statements) were redeemed and following such redemption, the agreements governing the GBDC 3 2022 Debt Securitization were terminated. 2018 Debt Securitization - On November 18, 2024, in conjunction with the 2024 Debt Securitization, the 2018 Notes (as defined in Note 7 of our consolidated financial statements) were redeemed and following such redemption, the agreements governing the 2018 Debt Securitization were terminated. GCIC 2018 Debt Securitization - Effective September 16, 2019, we assumed as a result of the GCIC Merger, the GCIC 2018 Debt Securitization. On November 18, 2024, in conjunction with the 2024 Debt Securitization, the GCIC 2018 Notes (as defined in Note 7 of our consolidated financial statements) were redeemed and following such redemption, the agreements governing the GCIC 2018 Debt Securitization were terminated. GBDC 3 2021 Debt Securitization - Effective June 3, 2024, we assumed as a result of the GBDC 3 Merger, the GBDC 3 2021 Debt Securitization. On November 18, 2024, in conjunction with the 2024 Debt Securitization, the GBDC 3 2021 Notes (as defined in Note 7 of our consolidated financial statements) were redeemed and following such redemption, the agreements governing the GBDC 3 2021 Debt Securitization were terminated. GBDC 3 2022-2 Debt Securitization - Effective June 3, 2024, we assumed as a result of the GBDC 3 Merger, the GBDC 3 2022-2 Debt Securitization. On December 16, 2024, the GBDC 3 2022-2 Notes (as defined in Note 7 of our consolidated financial statements) were redeemed and following such redemption, the agreements governing the GBDC 3 2022-2 Notes were terminated. Due to the interplay of the 1940 Act restrictions on principal and joint transactions and the U.S. risk retention rules adopted pursuant to Section 941 of Dodd-Frank, as a business development company, we sought and received no action relief from the SEC to ensure we could engage in CLO financings in which assets are transferred through GC Advisors. 2026 Notes On February 24, 2021, we issued $400.0 million in aggregate principal amount of the 2026 Notes. On October 13, 2021, we issued an additional $200.0 million in aggregate principal of the 2026 Notes. As of both June 30, 2026 and September 30, 2025, we had $600.0 million of outstanding aggregate principal amount of the 2026 Notes. 2027 Notes On July 27, 2021, we issued $350.0 million in aggregate principal amount of the 2027 Notes, all of which remained outstanding as our debt as of both June 30, 2026 and September 30, 2025. 2028 Notes On December 5, 2023, we issued $450.0 million in aggregate principal amount of the 2028 Notes, On September 19, 2025, we issued an additional $250.0 million in aggregate principal of the 2028 Notes under the same terms of the original issuance, other than the issue date and the issue price. As of both June 30, 2026 and September 30, 2025, we had $700.0 million of outstanding aggregate principal amount of the 2028 Notes. On December 5, 2023, we entered into an interest rate swap on the 2028 Notes pursuant to which we agreed to receive a fixed rate of 7.310% and pay a rate of one-month Term SOFR plus 3.327%. The interest rate swap is designated as an effective hedge accounting instrument. The notional amount of the swap is $225.0 million and terminates on November 5, 2028. On April 10, 2024, we entered into an interest rate swap on the remaining portion of the initial $450.0 million of 2028 Notes pursuant to which we agreed to receive a fixed rate of 7.310% and pay a rate of one-month SOFR plus 2.835%. The interest rate swap is designated as an effective hedge accounting instrument. The notional amount of the swap is $225.0 million and terminates on November 5, 2028. On September 19, 2025, we entered into an interest rate swap on the additional $250.0 million in aggregate principal of the 2028 Notes, pursuant to which we agreed to receive a fixed rate of 5.050% and pay a floating interest rate of 165 TABLE OF CONTENTS SOFR plus 1.723%. The interest rate swap is designated as an effective hedge accounting instrument. The notional amount of the swap is $250.0 million and terminates on December 5, 2028. The carrying value of the 2028 Notes is inclusive of an adjustment for the change in fair value of an effective hedge accounting relationship. 2029 Notes On February 1, 2024, we issued $600.0 million in aggregate principal amount of the 2029 Notes, and on December 3, 2024, we issued an additional $150.0 million in aggregate principal amount of the 2029 Notes under the same terms of the original issuance other than the issue date and the issue price. As of both June 30, 2026 and September 30, 2025, we had $750.0 million of outstanding aggregate principal amount of the 2029 Notes. On January 29, 2024 and November 25, 2024, we entered into interest rate swap agreements on the 2029 Notes pursuant to which we agreed (i) to receive a fixed rate of 6.248% and pay a rate of one-month Term SOFR plus 2.444% on the first $600.0 million of the 2029 Notes and (ii) to receive a fixed rate of 5.881% and pay a rate of three-month SOFR plus 2.012% on the second $150.0 million of the 2029 Notes. The interest rate swap agreements are designated as effective hedge accounting instruments. The aggregate notional amount of the swap is $750.0 million and terminates on June 15, 2029. The carrying value of the 2029 Notes is inclusive of an adjustment for the change in fair value of an effective hedge accounting relationship. 2031 Notes On May 27, 2026, we issued $500.0 million in aggregate principal amount of the 2031 Notes, all of which remained outstanding as our debt as of June 30, 2026. On May 27, 2026, we entered into interest rate swap agreements on the 2031 Notes pursuant to which we agreed to (i) receive a fixed rate of 6.250% and pay a rate of SOFR + 2.171% on the first $350.0 million of the 2031 Notes, (ii) receive a fixed rate of 6.250% and pay a rate of SOFR + 2.203% on the second $75.0 million of the 2031 Notes and (iii) receive a fixed rate of 6.250% and pay a rate of SOFR + 2.185% on the remaining $75.0 million of the 2031 Notes. The interest rate swap agreements are designated as effective hedge accounting instruments. The aggregate notional amount of the swap is $500.0 million and terminates on June 1, 2031. The carrying value of the 2031 Notes is inclusive of an adjustment for the change in fair value of an effective hedge accounting relationship. Equity Distribution Agreement On October 6, 2023, we entered into an equity distribution agreement, or, as amended, the 2023 Equity Distribution Agreement (as defined in Note 2 of our consolidated financial statements), in connection with an at the market program to sell up to $288.0 million of shares of our common stock. An at the market offering is a registered offering by a publicly traded issuer of its listed equity securities that allows the issuer to sell shares directly into the market at market prices. During the nine months ended June 30, 2026, there were no common stock issuances under the 2023 Equity Distribution Agreement. During the nine months ended June 30, 2025, we issued 2.4 million shares of common stock for aggregate proceeds totaling $38.0 million under the 2023 Equity Distribution Agreement. As of June 30, 2026 and September 30, 2025, following an amendment to the 2023 Equity Distribution Agreement in May 2025 to increase the aggregate offering amount by $38.0 million, common stock with an aggregate offering amount of $250.0 million remained available for issuance under the 2023 Distribution Agreement. Asset Coverage, Contractual Obligations, Off-Balance Sheet Arrangements and Other Liquidity Considerations As of June 30, 2026, in accordance with the 1940 Act, with certain limited exceptions, we were allowed to borrow amounts such that our asset coverage, as defined in the 1940 Act, is at least 150% after such borrowing. Prior to February 6, 2019, in accordance with the 1940 Act, with certain limited exceptions, we were allowed to borrow amounts such that our asset coverage, as defined in the 1940 Act, was at least 200% after such borrowing. We currently intend to continue to target a GAAP debt-to-equity ratio between 0.85x to 1.25x. As of June 30, 2026, our asset coverage for borrowed amounts and GAAP debt-to-equity ratio was 180.4% and 1.24x, respectively, and our GAAP debt-to-equity ratio, net, which reduces total debt by cash, cash equivalents, foreign currencies and restricted cash held for partial repayment on notes of certain of our securitization vehicles past their reinvestment period term (if any) was 1.23x as of June 30, 2026. On July 31, 2026, our board of directors re-approved the Program (as defined in Note 2 of our consolidated financial statements), which allows us to repurchase up to $150.0 million of our outstanding common stock, exclusive of shares repurchased prior to the date of such authorization, on the open market at prices below the NAV per share as reported in our then most recently published consolidated financial statements. The Program is implemented at the 166 TABLE OF CONTENTS discretion of management with shares to be purchased from time to time at prevailing market prices, through open market transactions, including block transactions, in accordance with Rule 10b-18 under the Securities Exchange Act of 1934, as amended. During the nine months ended June 30, 2026, we repurchased 6.0 million shares of our common stock for an aggregate repurchase price of approximately $78.1 million. During the nine months ended June 30, 2025, we repurchased 2.5 million shares of our common stock for an aggregate repurchase price of approximately $35.5 million. As of June 30, 2026 and September 30, 2025, we had outstanding commitments to fund investments totaling $580.8 million and $927.9 million, respectively. As of June 30, 2026, total commitments of $580.8 million included $229.9 million of unfunded commitments on revolvers. There is no guarantee that these amounts will be funded to the borrowing party now or in the future. The unfunded commitments relate to loans with various maturity dates, but the entire amount was eligible for funding to the borrowers, subject to the terms of each loan’s respective credit agreement. A summary of maturity requirements for our principal borrowings as of June 30, 2026 is included in Note 7 of our consolidated financial statements. We did not have any other material contractual payment obligations as of June 30, 2026. As of June 30, 2026, we believe that we had sufficient assets and liquidity to adequately cover future obligations under our unfunded commitments based on historical rates of drawings upon unfunded commitments, cash and restricted cash balances that we maintain, availability under the Adviser Revolver and JPM Credit Facility, as well as ongoing principal repayments on debt investments. In addition, we generally hold some syndicated loans in larger portfolio companies that are saleable over a relatively short period to generate cash. In addition, we have entered and, in the future, could again enter into derivative instruments that contain elements of off-balance sheet market and credit risk. Refer to Note 5 of our consolidated financial statements for outstanding forward currency contracts and interest rate swap agreements as of June 30, 2026 and September 30, 2025. Derivative instruments can be affected by market conditions, such as interest rate volatility, which could impact the fair value of the derivative instruments. If market conditions move against us, we may not achieve the anticipated benefits of the derivative instruments and could realize a loss. We minimize market risk through monitoring its investments and borrowings. Although we expect to fund the growth of our investment portfolio through the net proceeds from future securities offerings and future borrowings, to the extent permitted by the 1940 Act, we cannot assure you that our efforts to raise capital will be successful. In addition, from time to time, we can amend or refinance our leverage facilities and securitization financings, to the extent permitted by applicable law. In addition to capital not being available, it also could not be available on favorable terms. To the extent we are not able to raise capital on what we believe are favorable terms, we will focus on optimizing returns by investing capital generated from repayments into new investments we believe are attractive from a risk/reward perspective. Furthermore, to the extent we are not able to raise capital and are at or near our targeted leverage ratios, we expect to receive smaller allocations, if any, on new investment opportunities under GC Advisors’ allocation policy and have, in the past, received such smaller allocations under similar circumstances. 167 TABLE OF CONTENTS Portfolio Composition, Investment Activity and Yield As of June 30, 2026 and September 30, 2025, we had investments in 424 and 417 portfolio companies, respectively, with a total fair value of $8.2 billion and $8.8 billion, respectively. The following table shows the asset mix of our new investment commitments for the three months ended June 30, 2026 and March 31, 2026 and the nine months ended June 30, 2026 and June 30, 2025: Three months ended Nine months ended June 30, 2026 March 31, 2026 June 30, 2026 June 30, 2025 (In thousands) Percentage (In thousands) Percentage (In thousands) Percentage (In thousands) Percentage Senior secured $ 708 5.6 % $ 1,000 5.6 % $ 4,708 6.3 % $ 104,665 5.1 % One stop 11,162 88.7 16,380 92.4 68,040 90.7 1,899,392 92.9 Second lien — — — — — — 14,027 0.7 Equity 715 5.7 354 2.0 2,226 3.0 25,767 1.3 Total new investment commitments $ 12,585 100.0 % $ 17,734 100.0 % $ 74,974 100.0 % $ 2,043,851 100.0 % For the nine months ended June 30, 2026, we had approximately $829.0 million in proceeds from principal payments and sales of portfolio investments. For the nine months ended June 30, 2025, we had approximately $1,146.0 million in proceeds from principal payments and sales of portfolio investments. The following table shows the principal, amortized cost and fair value of our portfolio of investments by asset class: As of June 30, 2026(1) As of September 30, 2025(2) Principal Amortized Cost Fair Value Principal Amortized Cost Fair Value (In thousands) (In thousands) Senior secured: Performing $ 391,521 $ 388,666 $ 384,933 $ 448,216 $ 443,940 $ 442,410 Non-accrual(3) 8,584 8,132 6,199 184 121 67 One stop: Performing 7,234,880 7,172,948 7,095,335 7,663,987 7,582,036 7,588,765 Non-accrual(3) 146,236 115,833 67,127 71,767 51,963 27,044 Second lien: Performing 23,004 22,874 22,877 26,093 25,882 26,199 Non-accrual(3) 5,416 3,724 — 5,224 3,725 210 Subordinated debt: Performing 36,594 36,407 36,171 38,444 38,027 38,412 Non-accrual(3) — — — — — — Equity: Performing N/A 509,890 498,395 N/A 613,585 646,282 Non-accrual(3) N/A 118,639 85,316 N/A 659 — Total $ 7,846,235 $ 8,377,113 $ 8,196,353 $ 8,253,915 $ 8,759,938 $ 8,769,389 (1)As of June 30, 2026, $1,788.9 million and $1,702.7 million of our loans at amortized cost and fair value, respectively, included a feature permitting a portion of the interest due on such loan to be PIK interest. As of June 30, 2026, $127.6 million and $73.4 million at amortized cost and fair value, respectively, of our loans with a PIK feature were on non-accrual status. (2)As of September 30, 2025, $1,520.7 million and $1,476.5 million of our loans at amortized cost and fair value, respectively, included a feature permitting a portion of the interest due on such loan to be PIK interest. As of September 30, 2025, $51.3 million and $24.1 million at amortized cost and fair value, respectively, of our loans with a PIK feature were on non-accrual status. (3)We refer to a loan as non-accrual when we cease recognizing interest income on the loan because we have stopped pursuing repayment of the loan or, in certain circumstances, it is past due 90 days or more on principal, interest or our management has reasonable doubt that principal or interest will be collected. Preferred equity securities accruing contractual PIK dividend income may be placed on non-accrual 168 TABLE OF CONTENTS status if there is reasonable doubt that the amortized cost or capitalized PIK and non-cash dividend income is collectible. See “— Critical Accounting Policies — Revenue Recognition.” As of June 30, 2026, we had loans in fifteen portfolio companies and preferred equity securities in five portfolio companies on non-accrual status, and non-accrual investments as a percentage of total investments at cost and fair value were 2.9% and 1.9%, respectively. As of September 30, 2025, we had loans in eight portfolio companies and preferred equity securities in one portfolio company on non-accrual status, and non-accrual investments as a percentage of total investments at cost and fair value were 0.6% and 0.3%, respectively. As of June 30, 2026 and September 30, 2025, the fair value of our debt investments as a percentage of the outstanding principal value was 97.0% and 98.4%, respectively. The following table shows the weighted average rate, spread over the applicable base rate of floating rate and fees of investments originated and the weighted average rate of sales and payoffs of portfolio companies during the three months ended June 30, 2026 and March 31, 2026 and the nine months ended June 30, 2026 and June 30, 2025: Three months ended Nine months ended June 30, 2026 March 31, 2026 June 30, 2026 June 30, 2025 Weighted average rate of new investment fundings 8.9% 8.8% 8.7% 9.3% Weighted average spread over the applicable base rate of new floating rate investment fundings 5.2% 4.9% 4.9% 5.1% Weighted average fees of new investment fundings 0.8% 0.7% 0.6% 0.8% Weighted average rate of sales and payoffs of portfolio investments(1) 9.3% 9.0% 9.2% 10.6% (1)Excludes the disposition of non-accrual assets. As of June 30, 2026, 97.9% and 98.0% of our debt portfolio at both amortized cost and at fair value, respectively, had interest rate floors that limit the minimum applicable interest rates on such loans. As of September 30, 2025, 98.0% of our debt portfolio at both amortized cost and at fair value had interest rate floors that limit the minimum applicable interest rates on such loans. As of June 30, 2026 and September 30, 2025, the portfolio median1 earnings before interest, taxes, depreciation and amortization, or EBITDA, for our portfolio companies was $75.4 million and $72.4 million, respectively. The portfolio median EBITDA is based on the most recently reported trailing twelve-month EBITDA received from the portfolio company. 169 TABLE OF CONTENTS 1 The portfolio median EBITDA is based on our portfolio of debt investments and excludes (i) portfolio companies with negative or de minimis EBITDA, (ii) investments designated as recurring revenue loans and (iii) portfolio companies with any loans on non-accrual status. As part of the monitoring process, GC Advisors regularly assesses the risk profile of each of our investments and rates each of them based on an internal system developed by Golub Capital and its affiliates. This system is not generally accepted in our industry or used by our competitors. It is based on the following categories, which we refer to as GC Advisors’ internal performance ratings: Internal Performance Ratings Rating Definition 5 Involves the least amount of risk in our portfolio. The borrower is performing above expectations, and the trends and risk factors are generally favorable. 4 Involves an acceptable level of risk that is similar to the risk at the time of origination. The borrower is generally performing as expected, and the risk factors are neutral to favorable. 3 Involves a borrower performing below expectations and indicates that the loan’s risk has increased somewhat since origination. The borrower could be out of compliance with debt covenants; however, loan payments are generally not past due. 2 Involves a borrower performing materially below expectations and indicates that the loan’s risk has increased materially since origination. In addition to the borrower being generally out of compliance with debt covenants, loan payments could be past due (but generally not more than 180 days past due). 1 Involves a borrower performing substantially below expectations and indicates that the loan’s risk has substantially increased since origination. Most or all of the debt covenants are out of compliance and payments are substantially delinquent. Loans rated 1 are not anticipated to be repaid in full and we will reduce the fair market value of the loan to the amount we anticipate will be recovered. Our internal performance ratings do not constitute any rating of investments by a nationally recognized statistical rating organization or represent or reflect any third-party assessment of any of our investments. For any investment rated 1, 2 or 3, GC Advisors will increase its monitoring intensity and prepare regular updates for the investment committee, summarizing current operating results and material impending events and suggesting recommended actions. GC Advisors monitors and, when appropriate, changes the internal performance ratings assigned to each investment in our portfolio. In connection with our valuation process, GC Advisors and our board of directors review these internal performance ratings on a quarterly basis. 170 TABLE OF CONTENTS The following table shows the distribution of our investments on the 1 to 5 internal performance rating scale at fair value as of June 30, 2026 and September 30, 2025: As of June 30, 2026 As of September 30, 2025 Internal Performance Rating Investments at Fair Value (In thousands) Percentage of Total Investments Investments at Fair Value (In thousands) Percentage of Total Investments 5 $ 140,649 1.7% $ 157,871 1.8% 4 6,958,677 84.9 7,683,585 87.6 3 869,177 10.6 843,352 9.6 2 227,850 2.8 84,581 1.0 1 — — — — Total $ 8,196,353 100.0% $ 8,769,389 100.0% The table below details the fair value of our debt investments as a percentage of the outstanding principal value by internal performance rating held as of June 30, 2026 and September 30, 2025: Average Price1 Category June 30, 2026 September 30, 2025 Internal Performance Ratings 4 and 5 (Performing At or Above Expectations) 98.7% 99.7% Internal Performance Rating 3 (Performing Below Expectations) 93.1 91.3 Internal Performance Ratings 1 and 2 (Performing Materially Below Expectations) 45.3 34.1 Total 97.0% 98.4% (1)Includes only debt investments held as of June 30, 2026 and September 30, 2025. Price reflects the fair value of debt investments as a percentage of the outstanding principal value by Internal Performance Rating category. The following table shows the distribution of our investments in our software industry segment on the 1 to 5 internal performance rating scale at fair value as of June 30, 2026 and September 30, 2025: As of June 30, 2026 As of September 30, 2025 Internal Performance Rating Software Investments at Fair Value (In thousands) Percentage of Total Software Investments Software Investments at Fair Value (In thousands) Percentage of Total Software Investments 5 $ 11,670 0.6% $ 19,288 0.8% 4 1,838,904 86.1 2,252,463 94.3 3 220,585 10.3 114,615 4.8 2 63,891 3.0 1,357 0.1 1 — — — — Total $ 2,135,050 100.0% $ 2,387,723 100.0% The table below details the fair value of our debt investments in our software industry segment as a percentage of the outstanding principal value by internal performance rating held as of June 30, 2026 and September 30, 2025. 171 TABLE OF CONTENTS Average Price1 Category June 30, 2026 September 30, 2025 Internal Performance Ratings 4 and 5 (Performing At or Above Expectations) 98.0% 99.8% Internal Performance Rating 3 (Performing Below Expectations) 95.1 94.5 Internal Performance Ratings 1 and 2 (Performing Materially Below Expectations) 29.2 36.0 Total 97.4% 99.6% (1)Includes only debt investments held as of June 30, 2026 and September 30, 2025. Price reflects the fair value of debt investments as a percentage of the outstanding principal value by Internal Performance Rating category. 172 TABLE OF CONTENTS Distributions We intend to make quarterly distributions to our stockholders as determined by our board of directors. For additional details on distributions, see “Income taxes” in Note 2 to our consolidated financial statements. We may not be able to achieve operating results that will allow us to make distributions at a specific level or to increase the amount of our distributions from time to time. In addition, the asset coverage requirements applicable to us as a business development company under the 1940 Act could limit our ability to make distributions. If we do not distribute a certain percentage of our income annually, we will suffer adverse U.S. federal income tax consequences, including the possible loss of our ability to be subject to tax as a RIC. We cannot assure stockholders that they will receive any distributions. Because federal income tax regulations differ from GAAP, distributions in accordance with tax regulations can differ from net investment income and realized gains recognized for financial reporting purposes. Differences are permanent or temporary. Permanent differences are reclassified within capital accounts in the financial statements to reflect their tax character. For example, permanent differences in classification result from the treatment of distributions paid from short-term gains as ordinary income dividends for tax purposes. Temporary differences arise when certain items of income, expense, gain or loss are recognized at some time in the future. To the extent our taxable earnings fall below the total amount of our distributions for any tax year, a portion of those distributions could be deemed a return of capital to our stockholders for U.S. federal income tax purposes. Thus, the source of a distribution to our stockholders could be the original capital invested by the stockholder rather than our income or gains. Stockholders should read any written disclosure accompanying a distribution payment carefully and should not assume that the source of any distribution is our ordinary income or gains. We have adopted an “opt out” dividend reinvestment plan for our common stockholders. As a result, if we declare a distribution, our stockholders’ cash distributions will be automatically reinvested in additional shares of our common stock unless a stockholder specifically “opts out” of our dividend reinvestment plan. If a stockholder opts out, that stockholder will receive cash distributions. Although distributions paid in the form of additional shares of our common stock will generally be subject to U.S. federal, state and local taxes in the same manner as cash distributions, stockholders participating in our dividend reinvestment plan will not receive any corresponding cash distributions with which to pay any such applicable taxes. 173 TABLE OF CONTENTS Related Party Transactions We have entered into a number of business relationships with affiliated or related parties, including the following: •We entered into the Investment Advisory Agreement with GC Advisors. Mr. Lawrence Golub, chief executive officer of GC Advisors and an interested director of Golub Capital BDC, and Mr. David Golub, our chairman and chief executive officer, are managers of GC Advisors, and each of Messrs. Lawrence Golub and David Golub own an indirect pecuniary interest in GC Advisors. The Board most recently approved an amended and restated Investment Advisory Agreement in May 2026. •Golub Capital LLC provides, and other affiliates of Golub Capital have historically provided, us with the office facilities and administrative services necessary to conduct day-to-day operations pursuant to our Administration Agreement. •We have entered into a license agreement with Golub Capital LLC, pursuant to which Golub Capital LLC has granted us a non-exclusive, royalty-free license to use the name “Golub Capital.” •Under a staffing agreement, or the Staffing Agreement, Golub Capital LLC has agreed to provide GC Advisors with the resources necessary to fulfill its obligations under the Investment Advisory Agreement. The Staffing Agreement provides that Golub Capital LLC will make available to GC Advisors experienced investment professionals and provide access to the senior investment personnel of Golub Capital LLC for purposes of evaluating, negotiating, structuring, closing and monitoring our investments. The Staffing Agreement also includes a commitment that the members of GC Advisors’ investment committee will serve in such capacity. Services under the Staffing Agreement are provided on a direct cost reimbursement basis. We are not a party to the Staffing Agreement. •GC Advisors serves as the collateral manager to the 2024 Issuer under the 2024 Issuer Collateral Management Agreement. Fees payable to GC Advisors for providing these services offset against the base management fee payable by us under the Investment Advisory Agreement. •We have entered into the Adviser Revolver with GC Advisors in order to have the ability to borrow funds on a short-term basis. •During the second calendar quarter of 2026, the Golub Capital Employee Grant Program Rabbi Trust, or the Trust, purchased approximately $31.4 million, or 2,425,911 shares of our common stock for the purpose of awarding incentive compensation to employees of Golub Capital. Through the first two calendar quarters of 2026, the Trust purchased approximately $50.1 million, or 3,925,911 shares of our common stock for the purpose of awarding incentive compensation to employees of Golub Capital. During the calendar year 2025, the Trust purchased approximately $45.1 million, or 3,089,459 shares of our common stock, for the purpose of awarding incentive compensation to employees of Golub Capital. •On September 16, 2019, we completed our acquisition of GCIC pursuant to the GCIC Merger Agreement. •On June 3, 2024, we completed our acquisition of GBDC 3, pursuant to the GBDC 3 Merger Agreement. GC Advisors also sponsors or manages, and expects in the future to sponsor or manage, other investment funds, accounts or investment vehicles (together referred to as “accounts”) that have investment mandates that are similar, in whole and in part, with ours. For example, GC Advisors presently serves as the investment adviser to Golub Capital Direct Lending Corporation, or GDLC, Golub Capital Direct Lending Unlevered Corporation, or GDLCU, Golub Capital BDC 4, Inc., or GBDC 4, Golub Capital Private Credit Fund, or GCRED, Golub Capital Private Income Fund I, or GPIF I, and Golub Capital Private Income Fund S, or GPIF S, all of which are unlisted business development companies that primarily focus on investing in one stop and other senior secured loans. In addition, our officers and directors serve in similar capacities for GDLC, GDLCU, GBDC 4, GCRED, GPIF I and GPIF S. If GC Advisors and its affiliates determine that an investment is appropriate for us, GDLC, GDLCU, GBDC 4, GCRED, GPIF I, GPIF S and other accounts, depending on the availability of such investment and other appropriate factors, and pursuant to GC Advisors’ allocation policy, GC Advisors or its affiliates could determine that we should invest side-by-side with one or more other accounts. We do not intend to make any investments if they are not permitted by applicable law and interpretive positions of the SEC and its staff, or if they are inconsistent with GC Advisors’ allocation procedures. 174 TABLE OF CONTENTS In addition, we have adopted a formal code of ethics that governs the conduct of our and GC Advisors’ officers, directors and employees. Our officers and directors also remain subject to the duties imposed by both the 1940 Act and the General Corporation Law of the State of Delaware. 175 TABLE OF CONTENTS Critical Accounting Policies The preparation of financial statements and related disclosures in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements and revenues and expenses during the periods reported. Actual results could materially differ from those estimates. We have identified the following items as critical accounting policies. Fair Value Measurements We value investments for which market quotations are readily available at their market quotations. However, a readily available market value is not expected to exist for many of the investments in our portfolio, and we value these portfolio investments at fair value as determined in good faith. Pursuant to Rule 2a-5 under the 1940 Act, our board of directors, as permitted, has designated GC Advisors as our valuation designee (the “Valuation Designee”) to perform the determination of fair value of our investments for which market quotations are not readily available, or valued by a third-party pricing service, in accordance with our valuation policies and procedures, subject to the oversight of our board of directors. Valuation methods include comparisons of the portfolio companies to peer companies that are public, determination of the enterprise value of a portfolio company, discounted cash flow analysis and a market interest rate approach. The factors that are taken into account in fair value pricing investments include: available current market data, including relevant and applicable market trading and transaction comparables; applicable market yields and multiples; security covenants; call protection provisions; information rights; the nature and realizable value of any collateral; the portfolio company’s ability to make payments, its earnings and discounted cash flows and the markets in which it does business; comparisons of financial ratios of peer companies that are public; comparable merger and acquisition transactions; and the principal market and enterprise values. When an external event such as a purchase transaction, public offering or subsequent equity sale occurs, the Valuation Designee will consider the pricing indicated by the external event to corroborate the valuation. Due to the inherent uncertainty of determining the fair value of investments that do not have a readily available market value, the fair value of the investments can differ significantly from the values that would have been used had a readily available market value existed for such investments and differ materially from values that are ultimately received or settled. Our Valuation Designee is ultimately and solely responsible for determining, in good faith, the fair value of investments that are not publicly traded, whose market prices are not readily available on a quarterly basis or any other situation where portfolio investments require a fair value determination. As part of the valuation process described below, the Valuation Designee discusses the valuation conclusions and determined the fair value of each portfolio investment in good faith. For periods ending on or before December 31, 2025, with respect to investments that are not publicly-traded or whose market price is not otherwise (a) readily available or (b) provided by a third-party pricing service or other quote: Our quarterly valuation process began with each portfolio company investment being initially valued by the investment professionals of the Valuation Designee responsible for the valuation function, with preliminary valuation conclusions documented and discussed with senior management. At least every other quarter, the valuation for each portfolio investment, subject to a de minimis threshold, was reviewed by an independent valuation firm. This valuation process was conducted at the end of each fiscal quarter, with each portfolio investment being reviewed at least every other quarter (subject to a de minimis threshold) with approximately 50% (based on the fair value of portfolio company investments) of our valuations of debt and equity investments without readily available market quotations subject to review by an independent valuation firm. For periods beginning after December 31, 2025, with respect to investments that are not publicly-traded or whose market price is not otherwise (a) readily available or (b) provided via a third-party pricing service or other quote, our Valuation Designee undertakes a multi-step valuation process each month. This monthly valuation process begins with each portfolio investment being initially valued either by (i) professionals of the Valuation Designee responsible for the valuation function or (ii) independent valuation firms that have been engaged to support the valuation of portfolio investments. Preliminary valuation conclusions are then documented and discussed with senior management and, in the case of valuations prepared by independent valuation firms, the Valuation Designee. Each month the valuation for each portfolio investment, or approximately 100% (based on the fair value of portfolio company investments) of our debt and equity investments without readily available market quotations (subject to a de minimis threshold) is either (i) performed by or (ii) reviewed by an independent valuation firm. 176 TABLE OF CONTENTS Determination of fair values involves subjective judgments and estimates. Under current accounting standards, the notes to our consolidated financial statements refer to the uncertainty with respect to the possible effect of such valuations, and any change in such valuations, on our consolidated financial statements. We follow ASC Topic 820 for measuring fair value. Fair value is the price that would be received in the sale of an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Where available, fair value is based on observable market prices or parameters, or derived from such prices or parameters. Where observable prices or inputs are not available, valuation models are applied. These valuation models involve some level of estimation and judgment, the degree of which is dependent on the price transparency for the assets or liabilities or market and the assets’ or liabilities’ complexity. Our fair value analysis, currently undertaken by the Valuation Designee, includes an analysis of the value of any unfunded loan commitments. Assets and liabilities are categorized for disclosure purposes based upon the level of judgment associated with the inputs used to measure their value. The valuation hierarchical levels are based upon the transparency of the inputs to the valuation of the asset or liability as of the measurement date. The three levels are defined as follows: Level 1: Inputs are unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date. Level 2: Inputs include quoted prices for similar assets or liabilities in active markets and inputs that are observable for the assets or liabilities, either directly or indirectly, for substantially the full term of the assets or liabilities. Level 3: Inputs include significant unobservable inputs for the assets or liabilities and include situations where there is little, if any, market activity for the assets or liabilities. The inputs into the determination of fair value are based upon the best information available and could require significant management judgment or estimation. In certain cases, the inputs used to measure fair value could fall into different levels of the fair value hierarchy. In such cases, an asset’s or a liability’s categorization within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. The Valuation Designee’s assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment, and the Valuation Designee considers factors specific to the asset or liability. The Valuation Designee assesses the levels of assets and liabilities at each measurement date, and transfers between levels are recognized on the actual date of the event or change in circumstances that caused the transfers. There were no transfers among Level 1, 2 and 3 of the fair value hierarchy for assets and liabilities during the nine months ended June 30, 2026 and 2025. The following section describes the valuation techniques used by us to measure different assets and liabilities at fair value and includes the level within the fair value hierarchy in which the assets and liabilities are categorized. 177 TABLE OF CONTENTS Valuation of Investments Level 1 investments are valued using quoted market prices. Level 2 investments are valued using market consensus prices that are corroborated by observable market data and quoted market prices for similar assets and liabilities. Level 3 investments are valued at fair value as determined in good faith by the Valuation Designee, based on input of the Valuation Designee’s personnel and independent valuation firms that have been engaged by or at the direction of the Valuation Designee to assist in the valuation of each portfolio investment without a readily available market quotation in accordance with the multi-step valuation process described above in “ — Fair Value Measurements”. For periods ending on or before December 31, 2025, at least every other quarter, the valuation for each portfolio investment (subject to a de minimis threshold) was reviewed by an independent valuation firm. This valuation process was conducted at the end of each fiscal quarter, with each portfolio investment being reviewed at least every other quarter (subject to a de minimis threshold) with approximately 50% (based on the fair value of portfolio company investments) of our valuations of debt and equity investments without readily available market quotations subject to review by an independent valuation firm. For periods beginning after December 31, 2025, the valuation process is conducted on a monthly basis and this monthly valuation process begins with each portfolio investment being initially valued, based on the fair value methodology in accordance with ASC Topic 820 described below, either by (i) professionals of the Valuation Designee responsible for the valuation function or (ii) investment valuation firms that have been engaged to support the valuation of portfolio investments. Each month the valuation for each portfolio investment, or approximately 100% (based on the fair value of portfolio company investments) of our debt and equity investments without readily available market quotations (subject to a de minimis threshold) was either (i) performed by or (ii) reviewed by an independent valuation firm. All investments as of June 30, 2026 and September 30, 2025 were valued using Level 3 inputs. As of June 30, 2026 and September 30, 2025, all money market funds included in cash equivalents and restricted cash equivalents were valued using Level 1 inputs and all forward currency contracts and interest rate swaps were valued using Level 2 inputs. When determining fair value of Level 3 debt and equity investments, the Valuation Designee could take into account the following factors, where relevant: the enterprise value of a portfolio company, the nature and realizable value of any collateral, the portfolio company’s ability to make payments and its earnings and discounted cash flows, the markets in which the portfolio company does business, comparisons to publicly-traded securities, and changes in the interest rate environment and the credit markets generally that could affect the price at which similar investments could be made and other relevant factors. The primary method for determining enterprise value uses a multiple analysis whereby appropriate multiples are applied to the portfolio company’s EBITDA. A portfolio company’s EBITDA could include pro-forma adjustments for items such as acquisitions, divestitures, or expense reductions. The enterprise value analysis is performed to determine the value of equity investments and to determine if debt investments are credit impaired. The Valuation Designee may also employ other valuation multiples to determine enterprise value, such as revenues. If debt investments are credit impaired, the Valuation Designee will use the enterprise value analysis or a liquidation basis analysis to determine fair value, which may include evaluating multiple recovery scenarios and weighting the expected outcomes based on their likelihood. For debt investments that are not determined to be credit impaired, the Valuation Designee uses a market interest rate yield analysis to determine fair value. In addition, for certain debt investments, the Valuation Designee could base its valuation on indicative bid and ask prices provided by an independent third-party pricing service or directly from independent brokers. Bid prices reflect the highest price that we and others could be willing to pay. Ask prices represent the lowest price that we and others could be willing to accept. The Valuation Designee generally uses the midpoint of the independent third-party market “bid” and “ask” quotes to determine the value of our portfolio investments but may use another value if the Valuation Designee determines it better represents the investment’s fair value. While market price quotes from third-party pricing sources may be available, the Valuation Designee has the discretion to seek and utilize independent quotes from independent broker dealers to determine the fair value of the applicable portfolio investment. The Valuation Designee may obtain and consider both “bid” and “ask” quotes from either independent third-party vendors or directly from independent brokers. Due to the inherent uncertainty of determining the fair value of Level 3 investments that do not have a readily available market value, the fair value of the investments could differ significantly from the values that would have been used had a market existed for such investments and could differ materially from the values that could ultimately be received or settled. Further, such investments are generally subject to legal and other restrictions or otherwise are less liquid than publicly-traded instruments. If we were required to liquidate a portfolio investment in a forced or liquidation sale, we could realize significantly less than the value at which such investment had previously been recorded. 178 TABLE OF CONTENTS Our investments are subject to market risk. Market risk is the potential for changes in the value due to market changes. Market risk is directly impacted by the volatility and liquidity in the markets in which the investments are traded. Other Financial Assets and Liabilities ASC Topic 820 requires disclosure of the fair value of financial instruments for which it is practical to estimate such value. As a result, with the exception of the line item titled “debt” which is reported at cost, all assets and liabilities approximate fair value on the Consolidated Statements of Financial Condition due to their short maturity. Revenue Recognition Our revenue recognition policies are as follows: Investments and Related Investment Income: Interest income is accrued based upon the outstanding principal amount and contractual interest terms of debt investments. Original issue discount, market discount or premium and certain loan origination or amendment fees that are deemed to be an adjustment to yield (“Loan Origination Fees”) are capitalized and we accrete or amortize such amounts over the life of the loan as interest income (“Discount Amortization”). For investments with contractual PIK interest, which represents contractual interest accrued and added to the principal balance that generally becomes due at maturity, we do not accrue PIK interest if the portfolio company valuation indicates that the PIK interest is not likely to be collectible. In addition, we could generate revenue in the form of amendment, structuring or due diligence fees, fees for providing managerial assistance, administrative agent fees, consulting fees and prepayment premiums on loans that are not deemed to be an adjustment to yield and record these fees as fee income when earned. We record prepayment premiums on loans as fee income. Dividend income on preferred equity securities is recorded as dividend income on an accrual basis to the extent that such amounts are payable by the portfolio company and are expected to be collected. We have certain preferred equity securities in our portfolio that contain a PIK dividend provision that are accrued and recorded as income at the contractual rates, if deemed collectible. The accrued PIK and non-cash dividends are capitalized to the cost basis of the preferred equity security and are generally collected when redeemed by the issuer. Dividend income on common equity securities is recorded on the record date for private portfolio companies or on the ex-dividend date for publicly traded portfolio companies. Distributions received from limited liability company, or LLC, and limited partnership, or LP, investments are evaluated to determine if the distribution should be recorded as dividend income or a return of capital. Generally, we will not record distributions from equity investments in LLCs and LPs as dividend income unless there are sufficient accumulated tax-basis earnings and profits in the LLC or LP prior to the distribution. Distributions that are classified as a return of capital are recorded as a reduction in the cost basis of the investment. We account for investment transactions on a trade-date basis. Realized gains or losses on investments are measured by the difference between the net proceeds from the disposition and the cost basis of investment, without regard to unrealized gains or losses previously recognized. We report changes in fair value of investments from the prior period that is measured at fair value as a component of the “Net change in unrealized appreciation (depreciation) on investment transactions” in our Consolidated Statements of Operations and fluctuations arising from the translation of foreign exchange rates on investments in “Net change in unrealized appreciation (depreciation) from translation of assets and liabilities in foreign currencies” on the Consolidated Statements of Operations. Non-accrual Investments: Loans may be left on accrual status during the period we are pursuing repayment of the loan. Management reviews all loans that become past due 90 days or more on principal and interest or when there is reasonable doubt that principal or interest will be collected for possible placement on non-accrual status. We generally reverse accrued interest when a loan is placed on non-accrual. Additionally, any original issue discount and market discount are no longer accreted to interest income as of the date the loan is placed on non-accrual status. Interest payments received on non-accrual loans could be recognized as income or applied to principal depending upon management’s judgment. We restore non-accrual loans to accrual status when past due principal and interest is paid and, in our management’s judgment, are likely to remain current. The total fair value of our non-accrual loans was $73.3 million and $27.3 million as of June 30, 2026 and September 30, 2025, respectively. We review all preferred equity securities accruing contractual PIK dividend income to determine if there is reasonable doubt that amortized cost or capitalized PIK and non-cash dividend income will be collected, for possible placement on non-accrual status. When a preferred equity security is placed on non-accrual status, the contractual PIK dividend provision is no longer accrued to dividend income as of the date the preferred equity security is placed on non-accrual status. As of June 30, 2026, there were five preferred equity securities on non-accrual status with a fair value of $85.3 million. As of September 30, 2025, there was one preferred equity security on non-accrual status with a fair value of $0.0 million. 179 TABLE OF CONTENTS Income taxes: We have elected to be treated as a RIC under Subchapter M of the Code and operate in a manner so as to qualify for the tax treatment applicable to RICs. In order to be subject to tax as a RIC, we are required to meet certain source of income and asset diversification requirements, as well as timely distribute to our stockholders dividends for U.S. federal income tax purposes of an amount generally at least equal to 90% of investment company taxable income, as defined by the Code and determined without regard to any deduction for dividends paid, for each tax year. We have made and intend to continue to make the requisite distributions to our stockholders, which will generally relieve us from U.S. federal income taxes. Depending on the level of taxable income earned in a tax year, we could choose to retain taxable income in excess of current year dividend distributions and would distribute such taxable income in the next tax year. We could then be required to incur a 4% excise tax on such income. To the extent that we determine that our estimated current year annual taxable income, determined on a calendar year basis, could exceed estimated current calendar year dividend distributions, we accrue excise tax, if any, on estimated excess taxable income as taxable income is earned. For both three and nine months ended June 30, 2026, we did not record any U.S. federal excise tax. For the three months ended June 30, 2025, we did not record any U.S. federal excise tax. For the nine months ended June 30, 2025, we recorded a reversal of the accrual for U.S. federal excise tax expense of $0.5 million. We have consolidated subsidiaries that are subject to U.S. federal and state corporate-level income taxes. For both the three and nine months ended June 30, 2026, we did not record any U.S. income taxes and we recorded a net tax expense of less than $0.1 million for taxable subsidiaries, which is reported within “(Provision) benefit for taxes on unrealized appreciation on investments” on the Consolidated Statements of Operations. For the three and nine months ended June 30, 2025, we did not record any U.S income taxes and we recorded a net tax benefit of $0.2 million and $0.4 million, respectively, for taxable subsidiaries. As of both June 30, 2026 and September 30, 2025, we recorded a net deferred tax liability, reported within “Accounts payable and other liabilities” on the Consolidated Statement of Financial Condition, of $0.2 million for taxable subsidiaries, primarily due to unrealized appreciation on the investments held at the taxable subsidiaries. Because federal income tax regulations differ from GAAP, distributions in accordance with tax regulations could differ from net investment income and realized gains recognized for financial reporting purposes. Differences could be permanent or temporary. Permanent differences are reclassified within capital accounts in the financial statements to reflect their tax character. For example, permanent differences in classification could result from the treatment of distributions paid from short-term gains as ordinary income dividends for tax purposes. Temporary differences arise when certain items of income, expense, gain, or loss are recognized at some time in the future. 180 TABLE OF CONTENTS