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INVESTMENTS - Schedule of Investments Classified by Contractual Maturity Date (Details) - USD ($) $ in Thousands | Sep. 30, 2025 | Sep. 30, 2024 | [2]
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Investments, Debt and Equity Securities [Abstract] |  |  |
2026 | $ 58,434 |  |
2027 | 157,554 |  |
2028 | 222,265 |  |
2029 | 139,336 |  |
2030 | 209,608 |  |
Thereafter | 10,000 |  |
Total contractual repayments | 797,197 |  |
Adjustments to cost basis of debt investments | (574) |  |
Investments in equity securities | 79,991 |  |
Investment owned, at cost | 876,614 | [1] | $ 771,011
Debt investments with maturity dates prior to period end | $ 500 |  |
[1] | Cumulative gross unrealized depreciation for federal income tax purposes is $59.7 million; cumulative gross unrealized appreciation for federal income tax purposes is $34.1 million. Cumulative net unrealized depreciation is $25.5 million, based on a tax cost of $884.7 million.
[2] | Cumulative gross unrealized depreciation for federal income tax purposes is $66.1 million; cumulative gross unrealized appreciation for federal income tax purposes is $85.8 million. Cumulative net unrealized appreciation is $19.7 million, based on a tax cost of $776.5 million

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