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CONSOLIDATED STATEMENTS OF ASSETS AND LIABILITIES (Parenthetical) - USD ($) $ in Thousands | Sep. 30, 2025 | Mar. 31, 2025
--- | --- | ---
Cost | $ 1,896,526 | [1],[2],[3],[4],[5] | $ 1,779,360 | [6],[7],[8],[9],[10],[11]
Accumulated amortization | 11,764 |  | 10,357 |
Unamortized debt issuance costs | $ 19,117 |  | $ 13,810 |
Common stock, par value (in usd per share) | $ 0.25 |  | $ 0.25 |
Common stock, authorized (in shares) | 75,000,000 |  | 75,000,000 |
Common stock, issued (in shares) | 56,966,998 |  | 52,912,796 |
Common stock, outstanding (in shares) | 56,966,998 |  | 52,912,796 |
SBA Debentures |  |  |  |
Unamortized debt issuance costs | $ 4,088 |  | $ 4,082 |
October 2026 Notes |  |  |  |
Unamortized debt issuance costs | 769 |  | 1,154 |
August 2028 Notes |  |  |  |
Unamortized debt issuance costs | 1,429 |  | 1,681 |
2029 Convertible Notes |  |  |  |
Unamortized debt issuance costs | 6,153 |  | 6,893 |
September 2030 Notes |  |  |  |
Unamortized debt issuance costs | 6,678 |  | 0 |
Non-control/Non-affiliate investments |  |  |  |
Cost | 1,490,045 |  | 1,403,623 |
Affiliate investments |  |  |  |
Cost | 334,800 |  | 304,824 |
Control investments |  |  |  |
Cost | $ 71,681 |  | $ 70,913 |
[1] | All debt investments are income-producing, unless otherwise noted. Equity investments are non-income producing, unless otherwise noted. (2)All of the Company’s investments, the investments of Capital Southwest SPV LLC ("SPV"), the investments of SBIC I (as defined below) and the investments of SBIC II (as defined below) are pledged as collateral for the Company’s senior secured revolving credit facility, the SPV's financing credit facility or in support of the SBA-guaranteed debentures to be issued by Capital Southwest SBIC I, LP ("SBIC I") and Capital Southwest SBIC II, LP ("SBIC II"), the Company's wholly-owned subsidiaries that operate as small business investment companies, respectively.
[2] | Non-Control/Non-Affiliate investments are generally defined by the 1940 Act as investments that are neither control investments nor affiliate investments. Investments are classified as non-control/non-affiliate investments, unless otherwise noted. At September 30, 2025, the Company held $1,488.4 million of non-control/non-affiliate investments, which represented approximately 79.3% of the Company’s investment assets. The fair value of these investments as a percent of net assets is 157.1%.
[3] | As of September 30, 2025, the cumulative gross unrealized appreciation for U.S. federal income tax purposes was approximately $112.3 million; cumulative gross unrealized depreciation for federal income tax purposes was $127.1 million. Cumulative net unrealized depreciation was $14.8 million, based on a tax cost of $1,885.0 million.
[4] | Equity ownership may be held in shares or units of a company that is either wholly owned by the portfolio company or under common control by the same parent company to the portfolio company.
[5] | Unless otherwise noted, all portfolio company headquarters are based in the United States.
[6] | As of March 31, 2025, the cumulative gross unrealized appreciation for U.S. federal income tax purposes was approximately $117.4 million; cumulative gross unrealized depreciation for federal income tax purposes was $108.2 million. Cumulative net unrealized depreciation was $9.2 million, based on a tax cost of $1,776.1 million.
[7] | Equity ownership may be held in shares or units of a company that is either wholly owned by the portfolio company or under common control by the same parent company to the portfolio company.
[8] | Negative cost in this column represents the original issue discount of certain undrawn revolvers and delayed draw term loans.
[9] | Unless otherwise noted, all portfolio company headquarters are based in the United States.
[10] | All debt investments are income-producing, unless otherwise noted. Equity investments are non-income producing, unless otherwise noted.
[11] | Non-Control/Non-Affiliate investments are generally defined by the 1940 Act as investments that are neither control investments nor affiliate investments. Investments are classified as non-control/non-affiliate investments, unless otherwise noted. At March 31, 2025, the Company held $1,436.3 million of non-control/non-affiliate investments, which represented approximately 80.5% of the Company’s investment assets. The fair value of these investments as a percent of net assets is 162.6%.

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