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INVESTMENTS - Schedule of Fair Value Measurement Inputs and Valuation Techniques (Details) $ in Thousands | Dec. 31, 2024 USD ($) | Mar. 31, 2024 USD ($)
--- | --- | ---
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair Value | $ 1,072,230 | $ 920,504 | [1]
Investments at fair value | 1,067,230 | 920,504 |
Secured First Lien Debt |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Investments at fair value | 599,911 | 474,856 |
Secured Second Lien Debt |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Investments at fair value | 108,743 | 138,703 |
Preferred Equity |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Investments at fair value | 308,226 | 213,480 |
Common Equity/ Equivalents |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Investments at fair value | 50,350 | 93,465 |
Common Equity/ Equivalents | Gladstone Alternative Income Fund ("GALT") |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Investments at fair value | 5,000 |  |
Significant Unobservable Inputs (Level 3) |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair Value | 1,067,230 | 920,486 |
Investments at fair value | 1,067,230 | 920,486 |
Significant Unobservable Inputs (Level 3) | Secured First Lien Debt |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Investments at fair value | 599,911 | 474,856 |
Significant Unobservable Inputs (Level 3) | Secured Second Lien Debt |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Investments at fair value | 108,743 | 138,703 |
Significant Unobservable Inputs (Level 3) | Preferred Equity |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Investments at fair value | 308,226 | 213,480 |
Significant Unobservable Inputs (Level 3) | Common Equity/ Equivalents |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Investments at fair value | 50,350 | 93,447 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | Secured First Lien Debt |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair Value | 599,911 | 474,856 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | Secured Second Lien Debt |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair Value | 96,229 | 113,703 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | Preferred Equity |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair Value | 308,226 | 213,480 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | Common Equity/ Equivalents |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair Value | $ 50,350 | $ 93,447 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | EBITDA multiple | Secured First Lien Debt | Minimum |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair value, measurement input | 2.8 | 4.2 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | EBITDA multiple | Secured First Lien Debt | Maximum |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair value, measurement input | 11.8 | 8.8 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | EBITDA multiple | Secured First Lien Debt | Weighted Average |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair value, measurement input | 6.8 | 6.4 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | EBITDA multiple | Secured Second Lien Debt | Minimum |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair value, measurement input | 5.7 | 5.1 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | EBITDA multiple | Secured Second Lien Debt | Maximum |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair value, measurement input | 7.0 | 15.0 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | EBITDA multiple | Secured Second Lien Debt | Weighted Average |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair value, measurement input | 6.6 | 7.0 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | EBITDA multiple | Preferred Equity | Minimum |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair value, measurement input | 2.8 | 4.2 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | EBITDA multiple | Preferred Equity | Maximum |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair value, measurement input | 11.8 | 8.8 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | EBITDA multiple | Preferred Equity | Weighted Average |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair value, measurement input | 6.0 | 6.1 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | EBITDA multiple | Common Equity/ Equivalents | Minimum |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair value, measurement input | 5.5 | 5.0 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | EBITDA multiple | Common Equity/ Equivalents | Maximum |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair value, measurement input | 8.1 | 15.0 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | EBITDA multiple | Common Equity/ Equivalents | Weighted Average |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair value, measurement input | 6.6 | 6.4 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | EBITDA | Secured First Lien Debt | Minimum |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair Value | $ 969 | $ 1,091 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | EBITDA | Secured First Lien Debt | Maximum |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair Value | 26,000 | 23,547 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | EBITDA | Secured First Lien Debt | Weighted Average |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair Value | 12,328 | 10,509 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | EBITDA | Secured Second Lien Debt | Minimum |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair Value | 4,489 | 5,648 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | EBITDA | Secured Second Lien Debt | Maximum |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair Value | 23,258 | 23,003 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | EBITDA | Secured Second Lien Debt | Weighted Average |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair Value | 14,721 | 14,192 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | EBITDA | Preferred Equity | Minimum |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair Value | 1,292 | 1,091 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | EBITDA | Preferred Equity | Maximum |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair Value | 26,000 | 23,547 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | EBITDA | Preferred Equity | Weighted Average |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair Value | 11,696 | 9,502 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | EBITDA | Common Equity/ Equivalents | Minimum |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair Value | 969 | 1,154 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | EBITDA | Common Equity/ Equivalents | Maximum |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair Value | 23,258 | 63,269 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | EBITDA | Common Equity/ Equivalents | Weighted Average |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair Value | $ 17,987 | $ 23,615 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | Revenue multiple | Secured First Lien Debt | Minimum |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair value, measurement input | 0.2 | 0.3 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | Revenue multiple | Secured First Lien Debt | Maximum |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair value, measurement input | 0.6 | 0.6 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | Revenue multiple | Secured First Lien Debt | Weighted Average |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair value, measurement input | 0.4 | 0.4 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | Revenue multiple | Preferred Equity | Minimum |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair value, measurement input | 0.2 | 0.3 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | Revenue multiple | Preferred Equity | Maximum |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair value, measurement input | 0.6 | 0.6 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | Revenue multiple | Preferred Equity | Weighted Average |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair value, measurement input | 0.3 | 0.4 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | Revenue | Secured First Lien Debt | Minimum |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair Value | $ 6,141 | $ 31,586 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | Revenue | Secured First Lien Debt | Maximum |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair Value | 100,934 | 93,916 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | Revenue | Secured First Lien Debt | Weighted Average |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair Value | 70,883 | 77,580 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | Revenue | Preferred Equity | Minimum |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair Value | 6,141 | 31,586 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | Revenue | Preferred Equity | Maximum |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair Value | 100,934 | 93,916 |
Significant Unobservable Inputs (Level 3) | Total Enterprise Value | Revenue | Preferred Equity | Weighted Average |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair Value | 52,338 | 75,099 |
Significant Unobservable Inputs (Level 3) | Yield Analysis | Secured Second Lien Debt |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair Value | $ 12,514 | $ 25,000 |
Significant Unobservable Inputs (Level 3) | Yield Analysis | Discount Rate | Secured Second Lien Debt | Minimum |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair value, measurement input | 0.197 | 0.138 |
Significant Unobservable Inputs (Level 3) | Yield Analysis | Discount Rate | Secured Second Lien Debt | Maximum |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair value, measurement input | 0.197 | 0.138 |
Significant Unobservable Inputs (Level 3) | Yield Analysis | Discount Rate | Secured Second Lien Debt | Weighted Average |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Fair value, measurement input | 0.197 | 0.138 |
Significant Other Observable Inputs (Level 2) |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Investments at fair value | $ 0 | $ 18 |
Significant Other Observable Inputs (Level 2) | Secured First Lien Debt |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Investments at fair value | 0 | 0 |
Significant Other Observable Inputs (Level 2) | Secured Second Lien Debt |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Investments at fair value | 0 | 0 |
Significant Other Observable Inputs (Level 2) | Preferred Equity |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Investments at fair value | 0 | 0 |
Significant Other Observable Inputs (Level 2) | Common Equity/ Equivalents |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Investments at fair value | $ 0 | 18 |
Significant Other Observable Inputs (Level 2) | Common Equity/ Equivalents | Funko Acquisition Holdings, LLC |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Investments at fair value |  | $ 18 |
[1] | 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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