We are subject to financial market risks, including changes in interest rates, and changes in interest rates may affect both our interest expense on the debt outstanding under our Credit Facilities and our interest income from portfolio investments. Our risk management systems and procedures are designed to identify and analyze our risk, to set appropriate policies and limits and to continually monitor these risks. Our investment income will be affected by changes in various interest rate indices, including SOFR and Prime rates, to the extent that any debt investments include floating interest rates. See Risk Factors — Risks Related to our Business and Structure — We are subject to risks associated with the interest rate environment and changes in interest rates will affect our cost of capital, net investment income and the value of our investments. and Risk Factors — Risks Related to Leverage — Because we borrow money, the potential for gain or loss on amounts invested in us is magnified and may increase the risk of investing in us. included in our Annual Report on Form 10-K for the fiscal year ended December 31, 2025 for more information regarding risks associated with our debt investments and borrowings that utilize SOFR or Prime as a reference rate. The majority of our debt investments are made with either fixed interest rates or floating rates that are subject to contractual minimum interest rates for the term of the investment. As of June 30, 2026, 61% of our Investment Portfolio debt investments (at cost) bore interest at floating rates, 96% of which were subject to contractual minimum interest rates. As of June 30, 2026, 91% of our debt obligations bore interest at fixed rates. Our interest expense will be affected by changes in the published SOFR in connection with our Credit Facilities; however, the interest rates on our outstanding March 2029 Notes, July 2026 Notes, June 2027 Notes, August 2028 Notes, SBIC debentures and April 2031 Notes, which collectively comprise the majority of our outstanding debt, are fixed for the life of such debt. As of June 30, 2026, we had not entered into any interest rate hedging arrangements. Due to our limited use of derivatives, we have claimed an exclusion from the definition of the term “commodity pool operator” under the Commodity Exchange Act and, therefore, are not subject to registration or regulation as a pool operator thereunder. The Company operates, and expects to continue to operate, as a “limited derivatives user” under Rule 18f-4 under the 1940 Act. In addition, the investment management and other services provided by our External Investment Manager also involve floating rate debt investments and floating rate debt obligations, and as a result the incentive fees earned by our External Investment Manager, and the corresponding benefits to our net investment income contributions from our External Investment Manager, are subject to change based upon any changes in floating benchmark index interest rates. 154 Table of contents The approximate annualized increase or decrease in the components of net investment income due to hypothetical base rate changes in interest rates, assuming no changes in our investments and borrowings, or in the investments and borrowings related to the investment management and other services provided by our External Investment Manager, in both cases, as of June 30, 2026, is as follows: Basis Point Change Increase (Decrease) in Interest Income (Increase) Decrease in Interest Expense Increase (Decrease) in Net Investment Income from the External Investment Manager (1) Increase (Decrease) in Net Investment Income Increase (Decrease) in Net Investment Income per Share (dollars in thousands, except per share amounts) (200) $ (45,033) $ 4,820 $ (2,356) $ (42,569) $ (0.46) (175) (40,142) 4,218 (2,063) (37,987) (0.41) (150) (34,541) 3,615 (1,641) (32,567) (0.35) (125) (28,788) 3,013 (974) (26,749) (0.29) (100) (23,034) 2,410 (617) (21,241) (0.23) (75) (17,281) 1,808 (463) (15,936) (0.17) (50) (11,528) 1,205 (309) (10,632) (0.11) (25) (5,774) 603 (155) (5,326) (0.06) 25 5,669 (603) 152 5,218 0.06 50 11,262 (1,205) 302 10,359 0.11 75 16,760 (1,808) 600 15,552 0.17 100 22,257 (2,410) 747 20,594 0.22 125 27,755 (3,013) 893 25,635 0.27 150 33,253 (3,615) 1,039 30,677 0.33 175 38,751 (4,218) 1,185 35,718 0.38 200 44,249 (4,820) 1,332 40,761 0.44 ___________________________ (1)Main Street’s total contribution from the External Investment Manager is based on the performance of assets managed by the External Investment Manager (see Note D — External Investment Manager in the notes to the consolidated financial statements included in Item 1. Consolidated Financial Statements of this Quarterly Report on Form 10-Q), and any related cost of debt obligations related to such managed assets, which may fluctuate depending on changes in interest rates. Although we believe that this analysis is indicative of the impact of interest rate changes to our net investment income as of June 30, 2026, the analysis does not take into consideration future changes in the credit market, credit quality or other business or economic developments that could affect our net investment income. Accordingly, we can offer no assurances that actual results would not differ materially from the analysis above. The hypothetical results assume that all SOFR and Prime rate changes would be effective on the first day of the period. However, the contractual SOFR and Prime rate reset dates would vary throughout the period. The majority of our investments, and the investments managed by our External Investment Manager, are based on contracts which reset quarterly, while our Credit Facilities, and the debt obligations related to the assets managed by our External Investment Manager, reset monthly. The hypothetical results would also be impacted by the changes in the amount of outstanding debt under our Credit Facilities (with an increase (decrease) in the debt outstanding under the Credit Facilities resulting in an (increase) decrease in the hypothetical interest expense).