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FAIR VALUE MEASUREMENTS - Changes in Fair Value of Investments Measured Using Level 3 Inputs (Details) - USD ($) $ in Thousands | 6 Months Ended
--- | ---
Sep. 30, 2025 | Sep. 30, 2024
Total Investments |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Fair value, beginning balance | $ 1,785,299 | $ 1,476,561
Realized & Unrealized Gains (Losses) | (6,686) | (22,862)
Purchases of Investments | 245,933 | 203,549
Repayments | (116,483) | (132,221)
PIK Interest Capitalized | 6,115 | 6,065
Divestitures | (36,271) | (22,585)
Conversion/Exchange of Security | 0 | 0
Fair value. ending balance | 1,877,907 | 1,508,507
YTD Unrealized Appreciation (Depreciation) on Investments held at period end | 379 | (21,249)
First lien loans |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Fair value, beginning balance | 1,586,622 | 1,309,449
Realized & Unrealized Gains (Losses) | (19,113) | (14,912)
Purchases of Investments | 236,403 | 196,254
Repayments | (116,337) | (128,801)
PIK Interest Capitalized | 6,107 | 5,984
Divestitures | (1,789) | (22,585)
Conversion/Exchange of Security | (3,951) | 0
Fair value. ending balance | 1,687,942 | 1,345,389
YTD Unrealized Appreciation (Depreciation) on Investments held at period end | (16,012) | (15,970)
Second lien loans |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Fair value, beginning balance | 18,066 | 33,774
Realized & Unrealized Gains (Losses) | (922) | (1,986)
Purchases of Investments | 26 | (4)
Repayments | 0 | (3,420)
PIK Interest Capitalized | 0 | 70
Divestitures | 0 | 0
Conversion/Exchange of Security | 0 | (1,062)
Fair value. ending balance | 17,170 | 27,372
YTD Unrealized Appreciation (Depreciation) on Investments held at period end | (922) | (106)
Subordinated debt |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Fair value, beginning balance | 1,218 | 1,336
Realized & Unrealized Gains (Losses) | 2 | 29
Purchases of Investments | 57 | 57
Repayments | (146) | 0
PIK Interest Capitalized | 8 | 11
Divestitures | 0 | 0
Conversion/Exchange of Security | 0 | (153)
Fair value. ending balance | 1,139 | 1,280
YTD Unrealized Appreciation (Depreciation) on Investments held at period end | 2 | 21
Preferred equity |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Fair value, beginning balance | 102,918 | 71,127
Realized & Unrealized Gains (Losses) | (7,860) | (132)
Purchases of Investments | 3,427 | 3,557
Repayments | 0 | 0
PIK Interest Capitalized | 0 | 0
Divestitures | (31,323) | 0
Conversion/Exchange of Security | (688) | 0
Fair value. ending balance | 66,474 | 74,552
YTD Unrealized Appreciation (Depreciation) on Investments held at period end | (3,475) | (132)
Common equity & warrants |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Fair value, beginning balance | 76,475 | 60,875
Realized & Unrealized Gains (Losses) | 20,922 | (5,861)
Purchases of Investments | 2,563 | 3,685
Repayments | 0 | 0
PIK Interest Capitalized | 0 | 0
Divestitures | (3,159) | 0
Conversion/Exchange of Security | 4,639 | 1,215
Fair value. ending balance | 101,440 | 59,914
YTD Unrealized Appreciation (Depreciation) on Investments held at period end | 20,501 | $ (5,062)
Earnout |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Fair value, beginning balance | 0 |
Realized & Unrealized Gains (Losses) | 285 |
Purchases of Investments | 3,457 |
Repayments | 0 |
PIK Interest Capitalized | 0 |
Divestitures | 0 |
Conversion/Exchange of Security | 0 |
Fair value. ending balance | 3,742 |
YTD Unrealized Appreciation (Depreciation) on Investments held at period end | $ 285 |

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