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INVESTMENTS - Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation (Details) - USD ($) $ in Thousands | 12 Months Ended |  |  |
--- | --- | --- | --- | ---
Mar. 31, 2025 | Mar. 31, 2024 | Jan. 31, 2025 | Oct. 31, 2023 | Mar. 31, 2023
New investments, repayments and settlements: |  |  |  |  |  |  |
Cost | $ 939,066 | [1] | $ 854,290 | [2] |  |  |
Fair Value | 979,320 | [1] | 920,504 | [2] |  |  |
Old World Christmas, Inc. |  |  |  |  |  |  |
New investments, repayments and settlements: |  |  |  |  |  |  |
Realized gain (loss) on preferred equity |  |  | (300) |  |  |  |
SFEG Holdings, Inc |  |  |  |  |  |  |
New investments, repayments and settlements: |  |  |  |  |  |  |
Cost |  |  |  |  |  | $ 4,800 |
Fair Value |  |  |  |  |  | $ 8,600 |
PSI Molded Plastics, Inc |  |  |  |  |  |  |
New investments, repayments and settlements: |  |  |  |  |  |  |
Cost | 16,400 |  |  |  | $ 16,400 |  |
Fair Value | 9,800 |  |  |  |  |  |
Total |  |  |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |  |  |
Beginning balance | 974,345 |  | 920,486 |  |  |  | $ 753,516
New investments, repayments and settlements: |  |  |  |  |  |  |
Issuances / originations | 216,217 |  | 183,924 |  |  |  |
Settlements / repayments | (123,600) |  | (28,000) |  |  |  |
Sales | (75,982) |  | (52,228) |  |  |  |
Transfers | 0 |  | 0 |  |  |  |
Ending balance | 974,345 |  | 920,486 |  |  |  |
Total | Debt and Equity Securities, Realized Gain (Loss) |  |  |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |  |  |
Total gain (loss) | 63,163 |  | 29,964 |  |  |  |
Total | Debt and Equity Securities, Unrealized Gain (Loss) |  |  |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |  |  |
Total gain (loss) | 36,423 |  | 62,319 |  |  |  |
Reversal of previously recorded (appreciation) depreciation upon realization | (62,362) |  | (29,009) |  |  |  |
Secured First Lien Debt |  |  |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |  |  |
Beginning balance | 514,334 |  | 474,856 |  |  |  | 437,517
New investments, repayments and settlements: |  |  |  |  |  |  |
Issuances / originations | 169,200 |  | 74,536 |  |  |  |
Settlements / repayments | (98,600) |  | (28,000) |  |  |  |
Sales | 0 |  | 0 |  |  |  |
Transfers | 0 |  | 0 |  |  |  |
Ending balance | 514,334 |  | 474,856 |  |  |  |
Secured First Lien Debt | Debt and Equity Securities, Realized Gain (Loss) |  |  |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |  |  |
Total gain (loss) | 0 |  | (4,550) |  |  |  |
Secured First Lien Debt | Debt and Equity Securities, Unrealized Gain (Loss) |  |  |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |  |  |
Total gain (loss) | (31,122) |  | (7,859) |  |  |  |
Reversal of previously recorded (appreciation) depreciation upon realization | 0 |  | 3,212 |  |  |  |
Secured Second Lien Debt |  |  |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |  |  |
Beginning balance | 103,580 |  | 138,703 |  |  |  | 75,734
New investments, repayments and settlements: |  |  |  |  |  |  |
Issuances / originations | 400 |  | 64,000 |  |  |  |
Settlements / repayments | (25,000) |  | 0 |  |  |  |
Sales | 0 |  | 0 |  |  |  |
Transfers | (9,790) |  | 0 |  |  |  |
Ending balance | 103,580 |  | 138,703 |  |  |  |
Secured Second Lien Debt | Debt and Equity Securities, Realized Gain (Loss) |  |  |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |  |  |
Total gain (loss) | 0 |  | (3,200) |  |  |  |
Secured Second Lien Debt | Debt and Equity Securities, Unrealized Gain (Loss) |  |  |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |  |  |
Total gain (loss) | (733) |  | (1,031) |  |  |  |
Reversal of previously recorded (appreciation) depreciation upon realization | 0 |  | 3,200 |  |  |  |
Preferred Equity |  |  |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |  |  |
Beginning balance | 302,163 |  | 213,480 |  |  |  | 222,585
New investments, repayments and settlements: |  |  |  |  |  |  |
Issuances / originations | 46,617 |  | 14,688 |  |  |  |
Settlements / repayments | 0 |  | 0 |  |  |  |
Sales | (26,390) |  | (50,726) |  |  |  |
Transfers | 9,790 |  | (8,621) |  |  |  |
Ending balance | 302,163 |  | 213,480 |  |  |  |
Preferred Equity | Debt and Equity Securities, Realized Gain (Loss) |  |  |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |  |  |
Total gain (loss) | 19,790 |  | 36,833 |  |  |  |
Preferred Equity | Debt and Equity Securities, Unrealized Gain (Loss) |  |  |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |  |  |
Total gain (loss) | 63,210 |  | 34,050 |  |  |  |
Reversal of previously recorded (appreciation) depreciation upon realization | (24,334) |  | (35,329) |  |  |  |
Common Equity/ Equivalents |  |  |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |  |  |
Beginning balance | 54,268 |  | 93,447 |  |  |  | $ 17,680
New investments, repayments and settlements: |  |  |  |  |  |  |
Issuances / originations | 0 |  | 30,700 |  |  |  |
Settlements / repayments | 0 |  | 0 |  |  |  |
Sales | (49,592) |  | (1,502) |  |  |  |
Transfers | 0 |  | 8,621 |  |  |  |
Ending balance | 54,268 |  | 93,447 |  |  |  |
Common Equity/ Equivalents | Debt and Equity Securities, Realized Gain (Loss) |  |  |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |  |  |
Total gain (loss) | 43,373 |  | 881 |  |  |  |
Common Equity/ Equivalents | Debt and Equity Securities, Unrealized Gain (Loss) |  |  |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |  |  |
Total gain (loss) | 5,068 |  | 37,159 |  |  |  |
Reversal of previously recorded (appreciation) depreciation upon realization | $ (38,028) |  | $ (92) |  |  |  |
[1] | Cumulative gross unrealized appreciation for federal income tax purposes is $183.3 million; cumulative gross unrealized depreciation for federal income tax purposes is $144.9 million. Cumulative net unrealized appreciation is $38.5 million, based on a tax cost of $940.9 million.
[2] | Cumulative gross unrealized appreciation for federal income tax purposes is $180.5 million; cumulative gross unrealized depreciation for federal income tax purposes is $115.8 million. Cumulative net unrealized appreciation is $64.7 million, based on a tax cost of $855.8 million.

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