FS Specialty Lending Fund (FSEN) 10-Q15 May 242024 Q1 Quarterly reportFinancial data

Company Profile

Cover Page

Cover Page - shares	3 Months Ended
Cover Page - shares	Mar. 31, 2024	May 01, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
Document Transition Report	false
Entity File Number	814-00841
Entity Registrant Name	FS Specialty Lending Fund
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	27-6822130
Entity Address, Address Line One	201 Rouse Boulevard
Entity Address, City or Town	Philadelphia
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	19112
City Area Code	215
Local Phone Number	495-1150
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		455,506,155
Entity Central Index Key	0001501729
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Amendment Flag	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands		Mar. 31, 2024		Dec. 31, 2023
Assets
Investments, at fair value		$ 1,801,272	[1],[2]	$ 1,523,196	[3],[4]
Cash and cash equivalents		186,949	[1],[2],[5]	486,059	[3],[4],[6]
Restricted cash		12,189		6,699
Receivable for investments sold and repaid		29,870		27,860
Interest receivable		15,321		15,093
Dividends receivable		351		360
Unrealized appreciation on swap contracts		196		0
Swap income receivable		1,119		36
Prepaid expenses and other assets		59		254
Total assets		2,047,326		2,059,557
Liabilities
Payable for investments purchased		60,589		61,596
Swap income payable		68		259
Shareholder distributions payable		0		27,740
Management fees payable		9,112		8,416
Administrative services expense payable		412		108
Interest payable		1,592		1,603
Trustees' fees payable		164		164
Other accrued expenses and liabilities		1,819		3,179
Total liabilities		468,709		497,502
Commitments and contingencies	[7]
Shareholders' equity
Preferred shares, $0.001 par value, 50,000,000 shares authorized, none issued and outstanding		0		0
Common shares, $0.001 par value, 700,000,000 shares authorized, 455,506,155 and 455,506,155 shares issued and outstanding, respectively		456		456
Capital in excess of par value		3,185,784		3,185,784
Accumulated earnings (deficit)		(1,607,623)		(1,624,185)
Total shareholders' equity		1,578,617		1,562,055
Total liabilities and shareholders' equity		$ 2,047,326		$ 2,059,557
Net asset value per common share at period end (in USD per share)		$ 3.47		$ 3.43
Repurchase Facility
Liabilities
Repurchase facility payable	[8]	$ 394,953		$ 394,437
Non-controlled/unaffiliated Investments
Assets
Investments, at fair value		1,686,939		1,414,684
Non-controlled/affiliated investments
Assets
Investments, at fair value		27,968		7,496
Controlled/affiliated investments
Assets
Investments, at fair value		$ 86,365		$ 101,016

[1]Security may be an obligation of one or more entities affiliated with the named company.[2]See Note 8 for additional information regarding the fair value of the Company’s financial instruments.[3]Security may be an obligation of one or more entities affiliated with the named company.[4]See Note 8 for additional information regarding the fair value of the Company’s financial instruments.[5]Includes $59,698 held in Allspring Government Money Market Fund with a 7-day yield of 5.2% as of March 31, 2024.[6]Includes $23,098 held in Allspring Government Money Market Fund with a 7-day yield of 5.3% as of December 31, 2023.[7]See Note 10 for a discussion of the Company's commitments and contingencies.[8]See Note 9 for a discussion of the Company's financing arrangements.

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2024		Dec. 31, 2023
Amortized cost	$ 1,857,014	[1]	$ 1,543,925	[2]
Preferred stock, par value (in USD per share)	$ 0.001		$ 0.001
Preferred stock, shares authorized	50,000,000		50,000,000
Preferred stock, shares issued	0		0
Preferred stock, shares outstanding	0		0
Common stock, par value (in USD per share)	$ 0.001		$ 0.001
Common stock, shares authorized	700,000,000		700,000,000
Common stock, shares issued	455,506,155		455,506,155
Common stock, shares outstanding	455,506,155		455,506,155
Repurchase Facility
Deferred financing cost on facilities payable	$ 5,047		$ 5,563
Non-controlled/unaffiliated Investments
Amortized cost	1,652,065		1,358,793
Non-Controlled/Affiliated
Amortized cost	45,231		25,601
Controlled/affiliated
Amortized cost	$ 159,718		$ 159,531

[1]Security may be an obligation of one or more entities affiliated with the named company.[2]Security may be an obligation of one or more entities affiliated with the named company.

Unaudited Consolidated Statemen

Unaudited Consolidated Statements of Operations - USD ($)		3 Months Ended
Unaudited Consolidated Statements of Operations - USD ($)		Mar. 31, 2024		Mar. 31, 2023
Investment income
Paid-in-kind interest income		$ 1,648,000		$ 4,502,000
Fee income		0		0
Total investment income		69,250,000		43,095,000
Operating expenses
Management fees		9,112,000		10,474,000
Administrative services expenses		1,535,000		1,320,000
Share transfer agent fees		919,000		751,000
Accounting and administrative fees		125,000		183,000
Interest expense	[1]	9,084,000		12,598,000
Trustees' fees		164,000		164,000
Other general and administrative expenses		1,098,000		703,000
Total operating expenses		22,037,000		26,193,000
Less: Management fee offset	[2]	0		(255,000)
Net expenses		22,037,000		25,938,000
Net investment income before taxes		47,213,000		17,157,000
Federal and state taxes		793,000		0
Net investment income		46,420,000		17,157,000
Realized and unrealized gain/loss
Net realized gain (loss) on investments:		4,190,000		(20,207,000)
Net realized gain (loss) on foreign currency		0		(120,000)
Net realized gain (loss) on swap contracts		2,327,000		12,000
Net change in unrealized (appreciation) depreciation on investments		(35,013,000)		(30,473,000)
Net change in unrealized appreciation (depreciation) on swap contracts		196,000		1,077,000
Net change in unrealized appreciation (depreciation) on foreign currency		(9,000)		0
Total net realized and unrealized gain (loss)		(28,309,000)		(49,711,000)
Net increase (decrease) in net assets resulting from operations		$ 18,111,000		$ (32,554,000)
Per share information—basic and diluted
Net increase (decrease) in net assets resulting from operations (Earnings per Share), basic (in USD per share)		$ 0.04		$ (0.07)
Net increase (decrease) in net assets resulting from operations (Earnings per Share), diluted (in USD per share)		$ 0.04		$ (0.07)
Weighted average shares outstanding, basic (in shares)		455,506,155		452,684,238
Weighted average shares outstanding, diluted (in shares)		455,506,155		452,684,238
Non-controlled/unaffiliated Investments
Investment income
Interest income		$ 61,799,000		$ 30,190,000
Paid-in-kind interest income		1,236,000		4,306,000
Fee income		412,000		97,000
Dividend income		4,350,000		5,690,000
Realized and unrealized gain/loss
Net realized gain (loss) on investments:		4,119,000		(8,848,000)
Net change in unrealized (appreciation) depreciation on investments		(21,017,000)		(24,519,000)
Non-Controlled/Affiliated
Investment income
Interest income		160,000		157,000
Paid-in-kind interest income		352,000	[3]	24,000
Realized and unrealized gain/loss
Net realized gain (loss) on investments:		71,000		(11,359,000)
Net change in unrealized (appreciation) depreciation on investments		842,000		(2,561,000)
Controlled/affiliated
Investment income
Interest income		881,000		2,459,000
Paid-in-kind interest income		60,000	[4]	172,000
Realized and unrealized gain/loss
Net realized gain (loss) on investments:		0
Net change in unrealized (appreciation) depreciation on investments		$ (14,838,000)		$ (3,393,000)

[1]See Note 9 for a discussion of the Company's financing arrangements.[2]See Note 4 for a discussion of the offset by FS/EIG Advisor, LLC, the Company's investment adviser, of certain management fees to which it was otherwise entitled during the applicable period.[3]Interest and PIK income presented for the three months ended March 31, 2024.[4]Interest and PIK income presented for the three months ended March 31, 2024.

Unaudited Consolidated Statem_2

Unaudited Consolidated Statements of Changes in Net Assets - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
Operations
Net investment income		$ 46,420	$ 17,157
Net realized gain (loss) on investments, foreign currency and swap contracts		6,517	(20,315)
Net change in unrealized appreciation (depreciation) on investments		(35,013)	(30,473)
Net change in unrealized appreciation (depreciation) on swap contracts		196	1,077
Net change in unrealized appreciation (depreciation) on foreign currency		(9)	0
Net increase (decrease) in net assets resulting from operations		18,111	(32,554)
Shareholder distributions
Distributions to shareholders	[1]	(1,549)	(13,584)
Net decrease in net assets resulting from shareholder distributions	[1]	(1,549)	(13,584)
Capital share transactions
Reinvestment of shareholder distributions	[2]	0	5,218
Net increase in net assets resulting from capital share transactions	[2]	0	5,218
Total increase (decrease) in net assets		16,562	(40,920)
Net assets at beginning of period		1,562,055	1,753,748
Net assets at end of period		$ 1,578,617	$ 1,712,828

[1] See Note 5 for a discussion of the sources of distributions paid by the Company. See Note 3 for a discussion of the Company's common share transactions.

Unaudited Consolidated Statem_3

Unaudited Consolidated Statements of Cash Flows - USD ($) $ in Thousands		3 Months Ended				12 Months Ended
		Mar. 31, 2024		Mar. 31, 2023		Dec. 31, 2023
Cash flows from operating activities
Net increase (decrease) in net assets resulting from operations		$ 18,111		$ (32,554)
Adjustments to reconcile net increase (decrease) in net assets resulting from operations to net cash provided by (used in) operating activities:
Purchases of long-term investments		(331,694)		(25,032)
Paid-in-kind interest		(1,648)		(4,502)
Proceeds from sales and repayments of long-term investments		132,117		284,570
Net proceeds from sales (purchases) of short-term investments		(105,513)		0
Net realized (gain) loss on investments		(4,190)		20,207
Net change in unrealized (appreciation) depreciation on investments		35,013		30,473
Net change in unrealized (appreciation) depreciation on swap contracts		(196)		(1,077)
Accretion of discount		(2,161)		(1,262)
Amortization of deferred financing costs and discount		516		1,238
(Increase) decrease in receivable for investments sold and repaid		(2,010)		7,022
(Increase) decrease in interest receivable		(228)		4,042
(Increase) decrease in dividends receivable		9		0
(Increase) decrease in swap income receivable		(1,083)		18
(Increase) decrease in prepaid expenses and other assets		195		46
Increase (decrease) in payable for investments purchased		(1,007)		0
Increase (decrease) in swap income payable		(191)		(26)
Increase (decrease) in management fees payable		696		(966)
Increase (decrease) in administrative services expense payable		304		(217)
Increase (decrease) in interest payable	[1]	(11)		(8,991)
Increase (decrease) in other accrued expenses and liabilities		(1,360)		(2,013)
Net cash provided by (used in) operating activities		(264,331)		270,976
Cash flows from financing activities
Shareholder distributions paid		(29,289)		(8,325)
Repayments of credit facilities	[1]	0		(305,676)
Deferred financing costs paid		0		(136)
Net cash provided by (used in) financing activities		(29,289)		(314,137)
Total increase (decrease) in cash, cash equivalents and restricted cash		(293,620)		(43,161)
Cash, cash equivalents and restricted cash at beginning of period		492,758		481,655		$ 481,655
Cash, cash equivalents and restricted cash at end of period		199,138	[2]	438,494	[2]	$ 492,758
Supplemental disclosure
Non-cash reinvestment of shareholder distributions		0		5,218
Non-cash purchases of investments		0		(3,284)
Non-cash sales of investments		0		3,284
Federal and state taxes paid		$ 1,245		$ 711

[1]See Note 9 for a discussion of the Company's financing arrangements. During the three months ended March 31, 2024 and 2023, the Company paid $8,579 and $20,351, respectively, in interest expense on the financing arrangements and Senior Secured Notes.[2]Includes cash and cash equivalents of $186,949 and restricted cash of $12,189. Restricted cash is the cash collateral required to be posted pursuant to the Company’s derivative contracts.

Unaudited Consolidated Statem_4

Unaudited Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
Statement of Cash Flows [Abstract]
Interest expense paid		$ 8,579	$ 20,351
Cash and cash equivalents	[1],[2],[3]	186,949
Restricted cash		$ 12,189

[1]Includes $59,698 held in Allspring Government Money Market Fund with a 7-day yield of 5.2% as of March 31, 2024.[2]Security may be an obligation of one or more entities affiliated with the named company.[3]See Note 8 for additional information regarding the fair value of the Company’s financial instruments.

Unaudited Consolidated Schedule

Unaudited Consolidated Schedule of Investments - USD ($) $ in Thousands		Mar. 31, 2024		Dec. 31, 2023		Dec. 31, 2022
Percent of net assets		114.10%	[1]	97.50%	[2]
Amortized Cost		$ 1,857,014	[1]	$ 1,543,925	[2]
Fair Value		$ 1,801,272	[1],[3]	$ 1,523,196	[2],[4]
Liabilities in excess of other assets percentage		(25.90%)	[1],[5]	(28.60%)	[2],[6]
Cash and other assets		$ 186,949	[1],[3],[7]	$ 486,059	[2],[4],[8]
Liabilities in Excess of Other Assets		(409,604)	[1],[3],[5]	(447,200)	[2],[4],[6]
Net Assets		1,578,617	[1],[3]	1,562,055	[2],[4]
Nomura Total Return Swap
Unrealized Appreciation (Depreciation)		$ 196		$ 0
Nomura Total Return Swap \| Nomura Global Financial Products, Inc.
Number of Shares		6,756,299		6,756,299
Interest Rate		1.15%	[9]	1.15%	[10]
Notional Amount		$ 40,065		$ 38,308
Unrealized Appreciation (Depreciation)		$ 0		$ 0
Nomura Total Return Swap \| BNP Paribas, Aretec Group, Inc
Number of Shares		0
Interest Rate	[9]	4.50%
Notional Amount		$ 7,481
Unrealized Appreciation (Depreciation)		$ 37
Nomura Total Return Swap \| BNP Paribas, BCPE Empire Holdings, Inc.
Number of Shares		0
Interest Rate	[9]	4%
Notional Amount		$ 7,500
Unrealized Appreciation (Depreciation)		$ 13
Nomura Total Return Swap \| BNP Paribas, Charlotte Buyer, Inc.
Number of Shares		0
Interest Rate	[9]	5.25%
Notional Amount		$ 7,481
Unrealized Appreciation (Depreciation)		$ 18
Nomura Total Return Swap \| BNP Paribas, Clear Channel Outdoor Holdings, Inc.
Number of Shares		0
Interest Rate	[9]	3.50%
Notional Amount		$ 7,500
Unrealized Appreciation (Depreciation)		$ 66
Nomura Total Return Swap \| BNP Paribas, Clydesdale Acquisition Holdings Inc.
Number of Shares		0
Interest Rate	[9]	3.68%
Notional Amount		$ 7,481
Unrealized Appreciation (Depreciation)		$ 35
Nomura Total Return Swap \| BNP Paribas, Mavis Tire Express Services TopCo, L.P.
Number of Shares		0
Interest Rate	[9]	3.75%
Notional Amount		$ 7,481
Unrealized Appreciation (Depreciation)		$ 5
Nomura Total Return Swap \| BNP Paribas, Pro Mach Group, Inc.
Number of Shares		0
Interest Rate	[9]	3.75%
Notional Amount		$ 7,500
Unrealized Appreciation (Depreciation)		$ 22
Investment, Identifier [Axis]: AI Aqua Merger Sub, Inc., Capital Goods 1
Variable rate (percent)		4.25%	[9],[11]	4.25%	[10],[12],[13]
Floor Rate (percent)		0.50%	[9],[11]	0.50%	[10],[12],[13]
Principal  Amount		$ 17,948	[11],[14]	$ 16,522	[12],[13],[15]
Amortized Cost		17,804	[11]	16,398	[12],[13]
Fair Value		$ 18,051	[3],[11]	$ 16,625	[4],[12],[13]
Investment, Identifier [Axis]: AI Aqua Merger Sub, Inc., Capital Goods 2
Variable rate (percent)		4.25%	[9],[16]	4.25%	[10],[13],[17]
Floor Rate (percent)		0.50%	[9],[16]	0.50%	[10],[13],[17]
Principal  Amount		$ 2,052	[14],[16]	$ 3,478	[13],[15],[17]
Amortized Cost		2,052	[16]	3,452	[13],[17]
Fair Value		$ 2,064	[3],[16]	$ 3,500	[4],[13],[17]
Investment, Identifier [Axis]: AIRRO (Mauritius) Holdings II, Energy—Power
Variable rate (percent)		4%	[9],[18],[19],[20]	4%	[10],[21],[22],[23]
PIK Rate (percent)		3%	[9],[18],[19],[20]	3%	[10],[21],[22],[23]
Floor Rate (percent)		1.50%	[9],[18],[19],[20]	1.50%	[10],[21],[22],[23]
Principal  Amount		$ 14,865	[14],[18],[19],[20]	$ 22,856	[15],[21],[22],[23]
Amortized Cost		13,405	[18],[19],[20]	20,779	[21],[22],[23]
Fair Value		$ 14,832	[3],[18],[19],[20]	$ 23,050	[4],[21],[22],[23]
Investment, Identifier [Axis]: AIRRO (Mauritius) Holdings II, Energy—Power \| Maximum
PIK Rate (percent)		3%	[9],[18],[19],[20]	3%	[10],[21],[22],[23]
Investment, Identifier [Axis]: AIRRO (Mauritius) Holdings II, Warrants, Strike, Energy—Power
Number of Shares	[18],[19],[20],[24]	35
Amortized Cost	[18],[19],[20],[24]	$ 2,652
Fair Value	[3],[18],[19],[20],[24]	$ 0
Strike price (in dollars per share)	[1],[18],[19],[20],[24]	$ 1
Investment, Identifier [Axis]: AIRRO (Mauritius) Holdings II, Warrants, Strike: $1.00, Energy—Power
Number of Shares	[21],[22],[23],[25]			35
Amortized Cost	[21],[22],[23],[25]			$ 2,652
Fair Value	[4],[21],[22],[23],[25]			$ 0
Strike price (in dollars per share)	[2],[21],[22],[23],[25]			$ 1
Investment, Identifier [Axis]: Abaco Energy Technologies LLC, Common Equity, Energy—Service & Equipment
Number of Shares		6,944,444	[18],[24]	6,944,444	[21],[25]
Amortized Cost		$ 6,980	[18],[24]	$ 6,944	[21],[25]
Fair Value		$ 685	[3],[18],[24]	$ 1,375	[4],[21],[25]
Investment, Identifier [Axis]: Abaco Energy Technologies LLC, Preferred Equity, Energy—Service & Equipment
Number of Shares		28,942,003	[7],[18],[24]	28,942,003	[21],[25]
Amortized Cost		$ 1,447	[7],[18],[24]	$ 1,447	[21],[25]
Fair Value		$ 5,709	[3],[7],[18],[24]	$ 10,159	[4],[21],[25]
Investment, Identifier [Axis]: Acrisure, LLC, Insurance
Variable rate (percent)		4.50%	[9],[11]	4.50%	[10],[12]
Principal  Amount		$ 25,112	[11],[14]	$ 20,175	[12],[15]
Amortized Cost		25,016	[11]	20,033	[12]
Fair Value		$ 25,269	[3],[11]	$ 20,251	[4],[12]
Investment, Identifier [Axis]: Aimbridge Acquisition Co. Inc., Consumer Services
Variable rate (percent)		3.75%	[9],[11]	3.75%	[10],[12]
Principal  Amount		$ 26,735	[11],[14]	$ 21,805	[12],[15]
Amortized Cost		25,778	[11]	21,036	[12]
Fair Value		$ 25,921	[3],[11]	$ 20,380	[4],[12]
Investment, Identifier [Axis]: AirSwift Holdings, Ltd., Common Equity, Commercial & Professional Services
Number of Shares		3,750,000	[18],[20],[24]	3,750,000	[21],[23],[25]
Amortized Cost		$ 6,029	[18],[20],[24]	$ 6,029	[21],[23],[25]
Fair Value		$ 3,806	[3],[18],[20],[24]	$ 3,413	[4],[21],[23],[25]
Investment, Identifier [Axis]: Allegiant Travel Co., Transportation
Rate (percent)		7.30%	[9],[20]	7.30%	[10],[23]
Principal  Amount		$ 10,601	[14],[20]	$ 10,601	[15],[23]
Amortized Cost		9,677	[20]	9,614	[23]
Fair Value		$ 10,556	[3],[20]	10,385	[4],[23]
Investment, Identifier [Axis]: Allied Downhole Technologies, LLC
Fair Value				$ 0		$ 8,436
Investment, Identifier [Axis]: Allied Universal Holdco LLC, Consumer Services 1
Variable rate (percent)		4.75%	[9],[11]	4.75%	[10],[12]
Floor Rate (percent)		0.50%	[9],[11]	0.50%	[10],[12]
Principal  Amount		$ 14,420	[11],[14]	$ 9,975	[12],[15]
Amortized Cost		14,302	[11]	9,841	[12]
Fair Value		$ 14,479	[3],[11]	$ 9,998	[4],[12]
Investment, Identifier [Axis]: Allied Universal Holdco LLC, Consumer Services 2
Variable rate (percent)		3.75%	[9],[11]	3.75%	[10],[12]
Floor Rate (percent)		0.50%	[9],[11]	0.50%	[10],[12]
Principal  Amount		$ 9,904	[11],[14]	$ 9,929	[12],[15]
Amortized Cost		9,615	[11]	9,627	[12]
Fair Value		9,902	[3],[11]	9,903	[4],[12]
Investment, Identifier [Axis]: Allied Wireline Services, LLC
Fair Value		7,235		22,200		63,888
Investment, Identifier [Axis]: Allied Wireline Services, LLC, Common Equity
Fair Value		$ 0		$ 0		10,463
Investment, Identifier [Axis]: Allied Wireline Services, LLC, Common Equity, Energy—Service & Equipment
Number of Shares		48,400	[18],[24],[26],[27]	48,400	[21],[25],[28],[29]
Amortized Cost		$ 1,527	[18],[24],[26],[27]	$ 1,527	[21],[25],[28],[29]
Fair Value		$ 0	[3],[18],[24],[26],[27]	$ 0	[4],[21],[25],[28],[29]
Investment, Identifier [Axis]: Allied Wireline Services, LLC, Energy—Service & Equipment
PIK Rate (percent)		10%	[9],[18],[24],[27],[30]	10%	[10],[21],[25],[29],[31]
Principal  Amount		$ 70,277	[14],[18],[24],[27],[30]	$ 70,277	[15],[21],[25],[29],[31]
Amortized Cost		70,277	[18],[24],[27],[30]	70,277	[21],[25],[29],[31]
Fair Value		$ 7,235	[3],[18],[24],[27],[30]	$ 22,200	[4],[21],[25],[29],[31]
Investment, Identifier [Axis]: Allied Wireline Services, LLC, Energy—Service & Equipment \| Maximum
PIK Rate (percent)		10%	[9],[18],[24],[27],[30]	10%	[10],[21],[25],[29],[31]
Investment, Identifier [Axis]: Allied Wireline Services, LLC, Warrants
Fair Value		$ 0		$ 0		0
Investment, Identifier [Axis]: Allied Wireline Services, LLC, Warrants, Energy—Service & Equipment
Number of Shares		22,000	[18],[24],[26],[27]	22,000	[21],[25],[28],[29]
Amortized Cost		$ 0	[18],[24],[26],[27]	$ 0	[21],[25],[28],[29]
Fair Value		$ 0	[3],[18],[24],[26],[27]	$ 0	[4],[21],[25],[28],[29]
Investment, Identifier [Axis]: Allspring Government Money Market Fund - Select Class, Money Market Fund
Rate (percent)		5.20%		5.30%
Fair Value		$ 59,698		$ 23,098
Investment, Identifier [Axis]: American Auto Auction Group, LLC, Capital Goods
Variable rate (percent)		5%	[9],[11],[32]	5%	[10],[12]
Floor Rate (percent)		0.80%	[9],[11],[32]	0.80%	[10],[12]
Principal  Amount		$ 23,913	[11],[14],[32]	$ 9,975	[12],[15]
Amortized Cost		23,634	[11],[32]	9,752	[12]
Fair Value		$ 23,816	[3],[11],[32]	$ 9,858	[4],[12]
Investment, Identifier [Axis]: Arena Energy, LP, Contingent Value Rights, Energy—Upstream
Number of Shares		126,632,117	[18]	126,632,117	[21],[25]
Amortized Cost		$ 351	[18]	$ 351	[21],[25]
Fair Value		$ 351	[3],[18]	$ 571	[4],[21],[25]
Investment, Identifier [Axis]: Aretec Escrow Issuer Inc., Financial Services
Rate (percent)		10%	[9],[11]	10%	[10],[12]
Principal  Amount		$ 7,000	[11],[14]	$ 7,000	[12],[15]
Amortized Cost		7,000	[11]	7,000	[12]
Fair Value		$ 7,655	[3],[11]	$ 7,447	[4],[12]
Investment, Identifier [Axis]: Aretec Group, Inc., Financial Services
Variable rate (percent)		4.50%	[9],[11],[32]	4.50%	[10],[12],[13]
Principal  Amount		$ 6,834	[11],[14],[32]	$ 9,352	[12],[13],[15]
Amortized Cost		6,804	[11],[32]	9,071	[12],[13]
Fair Value		$ 6,881	[3],[11],[32]	$ 9,358	[4],[12],[13]
Investment, Identifier [Axis]: Ascent Resources Utica Holdings, LLC, Common Equity, Energy—Upstream
Number of Shares		1,486,929	[18],[24],[26]	1,486,929	[21],[25],[28]
Amortized Cost		$ 43,878	[18],[24],[26]	$ 44,573	[21],[25],[28]
Fair Value		$ 36,354	[3],[18],[24],[26]	$ 39,545	[4],[21],[25],[28]
Investment, Identifier [Axis]: Auris Luxembourg III S.a r.l, Health Care Equipment & Services
Variable rate (percent)		3.75%	[9],[11],[20]	3.75%	[10],[12],[23]
Principal  Amount		$ 20,234	[11],[14],[20]	$ 20,287	[12],[15],[23]
Amortized Cost		19,897	[11],[20]	19,912	[12],[23]
Fair Value		$ 20,303	[3],[11],[20]	$ 20,079	[4],[12],[23]
Investment, Identifier [Axis]: Aveanna Healthcare LLC, Health Care Equipment & Services
Variable rate (percent)		3.75%	[9],[11]	3.75%	[10],[12]
Floor Rate (percent)		0.50%	[9],[11]	0.50%	[10],[12]
Principal  Amount		$ 20,855	[11],[14]	$ 15,909	[12],[15]
Amortized Cost		18,746	[11]	14,054	[12]
Fair Value		$ 20,106	[3],[11]	$ 14,852	[4],[12]
Investment, Identifier [Axis]: BCPE Empire Holdings, Inc., Consumer Services
Variable rate (percent)		4%	[9],[11],[32]	4.75%	[10],[12]
Floor Rate (percent)		0.50%	[9],[11],[32]	0.50%	[10],[12]
Principal  Amount		$ 22,400	[11],[14],[32]	$ 24,900	[12],[15]
Amortized Cost		22,477	[11],[32]	24,983	[12]
Fair Value		$ 22,450	[3],[11],[32]	24,998	[4],[12]
Investment, Identifier [Axis]: Bridge Street Warehouse CLO IV Ltd., Financial Services
Rate (percent)	[9],[18],[20],[33],[34]	1.60%
Principal  Amount	[14],[18],[20],[33],[34]	$ 20,000
Amortized Cost	[18],[20],[33],[34]	20,329
Fair Value	[3],[18],[20],[33],[34]	20,329
Investment, Identifier [Axis]: Bridge Street Warehouse CLO IV, Ltd.
Fair Value		$ 20,329		$ 0
Investment, Identifier [Axis]: CCS-CMGC Holdings, Inc., Health Care Equipment & Services
Variable rate (percent)		5.50%	[9],[11]	5.50%	[10],[12]
Principal  Amount		$ 27,768	[11],[14]	$ 21,465	[12],[15]
Amortized Cost		24,052	[11]	18,225	[12]
Fair Value		$ 22,081	[3],[11]	$ 18,222	[4],[12]
Investment, Identifier [Axis]: CPM Holdings, Inc., Capital Goods
Variable rate (percent)		4.50%	[9],[11]	4.50%	[10],[12]
Floor Rate (percent)		0.50%	[9],[11]	0.50%	[10],[12]
Principal  Amount		$ 24,938	[11],[14]	$ 20,000	[12],[15]
Amortized Cost		25,010	[11]	20,038	[12]
Fair Value		$ 25,002	[3],[11]	$ 20,092	[4],[12]
Investment, Identifier [Axis]: CT Technologies Intermediate Holdings, Inc., Health Care Equipment & Services
Variable rate (percent)	[9],[11]	4.25%
Floor Rate (percent)	[9],[11]	0.80%
Principal  Amount	[11],[14]	$ 9,974
Amortized Cost	[11]	9,862
Fair Value	[3],[11]	$ 9,968
Investment, Identifier [Axis]: Charlotte Buyer, Inc., Health Care Equipment & Services
Variable rate (percent)		5.25%	[9],[11]	5.25%	[10],[12],[13]
Floor Rate (percent)		0.50%	[9],[11]	0.50%	[10],[12],[13]
Principal  Amount		$ 17,800	[11],[14]	$ 19,845	[12],[13],[15]
Amortized Cost		17,899	[11]	19,937	[12],[13]
Fair Value		$ 17,880	[3],[11]	$ 19,952	[4],[12],[13]
Investment, Identifier [Axis]: CircusTrix Holdings, LLC, Consumer Services 1
Variable rate (percent)		6.50%	[9],[11],[18]	6.75%	[10],[12],[21]
Floor Rate (percent)		1%	[9],[11],[18]	1%	[10],[12],[21]
Principal  Amount		$ 20,863	[11],[14],[18]	$ 20,915	[12],[15],[21]
Amortized Cost		20,863	[11],[18]	20,915	[12],[21]
Fair Value		$ 21,202	[3],[11],[18]	$ 21,098	[4],[12],[21]
Investment, Identifier [Axis]: CircusTrix Holdings, LLC, Consumer Services 2
Variable rate (percent)		6.50%	[9],[16],[18]	6.75%	[10],[17],[21]
Floor Rate (percent)		1%	[9],[16],[18]	1%	[10],[17],[21]
Principal  Amount		$ 2,688	[14],[16],[18]	$ 2,688	[15],[17],[21]
Amortized Cost		2,688	[16],[18]	2,688	[17],[21]
Fair Value		$ 2,732	[3],[16],[18]	$ 2,712	[4],[17],[21]
Investment, Identifier [Axis]: CircusTrix Holdings, LLC, Consumer Services 3
Variable rate (percent)		6.50%	[9],[16],[18]	6.75%	[10],[17],[21]
Floor Rate (percent)		1%	[9],[16],[18]	1%	[10],[17],[21]
Principal  Amount		$ 1,344	[14],[16],[18]	$ 1,344	[15],[17],[21]
Amortized Cost		1,344	[16],[18]	1,344	[17],[21]
Fair Value		$ 1,366	[3],[16],[18]	$ 1,356	[4],[17],[21]
Investment, Identifier [Axis]: Cirque Du Soleil Holding USA Newco, Inc., Financial Services
Variable rate (percent)		4.25%	[9],[11]	4.25%	[10],[12],[13]
Floor Rate (percent)		0.50%	[9],[11]	0.50%	[10],[12],[13]
Principal  Amount		$ 8,365	[11],[14]	$ 6,387	[12],[13],[15]
Amortized Cost		8,317	[11]	6,331	[12],[13]
Fair Value		$ 8,377	[3],[11]	$ 6,372	[4],[12],[13]
Investment, Identifier [Axis]: Citizen Energy Operating, LLC, Energy—Upstream
Variable rate (percent)		7.65%	[9],[11],[18]	7.65%	[10],[12],[21]
Floor Rate (percent)		1%	[9],[11],[18]	1%	[10],[12],[21]
Principal  Amount		$ 34,000	[11],[14],[18]	$ 35,000	[12],[15],[21]
Amortized Cost		33,540	[11],[18]	34,527	[12],[21]
Fair Value		$ 33,581	[3],[11],[18]	$ 34,426	[4],[12],[21]
Investment, Identifier [Axis]: Clear Channel Outdoor Holdings, Inc., Media & Entertainment
Variable rate (percent)		4%	[9],[11],[20]	3.50%	[10],[12],[23]
Principal  Amount		$ 12,500	[11],[14],[20]	$ 20,000	[12],[15],[23]
Amortized Cost		12,258	[11],[20]	19,551	[12],[23]
Fair Value		$ 12,516	[3],[11],[20]	$ 19,829	[4],[12],[23]
Investment, Identifier [Axis]: Clydesdale Acquisition Holdings Inc., Financial Services
Variable rate (percent)	[9],[11]	3.75%
Floor Rate (percent)	[9],[11]	0.50%
Principal  Amount	[11],[14]	$ 17,405
Amortized Cost	[11]	17,312
Fair Value	[3],[11]	$ 17,449
Investment, Identifier [Axis]: Clydesdale Acquisition Holdings Inc., Financials Services
Variable rate (percent)	[10],[12]			4.18%
Floor Rate (percent)	[10],[12]			0.50%
Principal  Amount	[12],[15]			$ 19,949
Amortized Cost	[12]			19,740
Fair Value	[4],[12]			$ 20,061
Investment, Identifier [Axis]: Cox Oil Offshore, LLC, Volumetric Production Payments, Energy—Upstream
Rate (percent)	[10],[21],[35],[36]			12.90%
Principal  Amount	[15],[21],[35],[36]			$ 100,000
Amortized Cost	[21],[35],[36]			1,129
Fair Value	[4],[21],[35],[36]			$ 1,234
Investment, Identifier [Axis]: Crown SubSea Communication Holding, Inc., Capital Goods
Variable rate (percent)	[9],[11]	4.75%
Floor Rate (percent)	[9],[11]	0.80%
Principal  Amount	[11],[14]	$ 6,000
Amortized Cost	[11]	5,941
Fair Value	[3],[11]	$ 6,042
Investment, Identifier [Axis]: Crown SubSea Communications Holding, Inc., Capital Goods 1
Variable rate (percent)	[10],[12],[13]			5%
Floor Rate (percent)	[10],[12],[13]			0.80%
Principal  Amount	[12],[13],[15]			$ 4,500
Amortized Cost	[12],[13]			4,523
Fair Value	[4],[12],[13]			$ 4,534
Investment, Identifier [Axis]: Crown SubSea Communications Holding, Inc., Capital Goods 2
Variable rate (percent)	[10],[12],[13]			5.25%
Floor Rate (percent)	[10],[12],[13]			0.80%
Principal  Amount	[12],[13],[15]			$ 5,430
Amortized Cost	[12],[13]			5,445
Fair Value	[4],[12],[13]			$ 5,468
Investment, Identifier [Axis]: Delivery Hero Finco LLC, Consumer Services
Variable rate (percent)	[9],[20],[32]	5%
Floor Rate (percent)	[9],[20],[32]	0.50%
Principal  Amount	[14],[20],[32]	$ 20,000
Amortized Cost	[20],[32]	19,900
Fair Value	[3],[20],[32]	$ 19,900
Investment, Identifier [Axis]: Digicel International Finance Ltd., Telecommunication Services
Variable rate (percent)	[9],[11]	5.15%
Floor Rate (percent)	[9],[11]	0.50%
Principal  Amount	[11],[14]	$ 20,000
Amortized Cost	[11]	19,236
Fair Value	[3],[11]	$ 19,400
Investment, Identifier [Axis]: Engineered Machinery Holdings, Inc., Capital Goods
Variable rate (percent)		3.75%	[9],[11]	3.50%	[10],[12]
Floor Rate (percent)		0.80%	[9],[11]	0.80%	[10],[12]
Principal  Amount		$ 24,860	[11],[14]	$ 19,924	[12],[15]
Amortized Cost		24,793	[11]	19,847	[12]
Fair Value		$ 24,806	[3],[11]	$ 19,840	[4],[12]
Investment, Identifier [Axis]: FR XIII PAA Holdings HoldCo, LLC, Energy—Midstream
Variable rate (percent)	[10],[12],[21]			7.50%
Floor Rate (percent)	[10],[12],[21]			0.50%
Principal  Amount	[12],[15],[21]			$ 17,047
Amortized Cost	[12],[21]			16,855
Fair Value	[4],[12],[21]			$ 17,156
Investment, Identifier [Axis]: First Brands Group, LLC, Automobiles & Components
Variable rate (percent)		5%	[9],[11]	5%	[10],[12]
Floor Rate (percent)		1%	[9],[11]	1%	[10],[12]
Principal  Amount		$ 24,841	[11],[14]	$ 19,905	[12],[15]
Amortized Cost		24,564	[11]	19,620	[12]
Fair Value		$ 24,910	[3],[11]	$ 19,781	[4],[12]
Investment, Identifier [Axis]: Full House Resorts, Inc., Consumer Services
Rate (percent)		8.30%	[9],[11]	8.30%	[10],[12]
Principal  Amount		$ 25,742	[11],[14]	$ 20,742	[12],[15]
Amortized Cost		23,419	[11]	18,561	[12]
Fair Value		24,622	[3],[11]	19,517	[4],[12]
Investment, Identifier [Axis]: GWP Midstream Holdco, LLC, Common Equity
Fair Value		$ 2,202		$ 1,661		5,044
Investment, Identifier [Axis]: GWP Midstream Holdco, LLC, Common Equity, Energy—Midstream
Number of Shares		105,785	[18],[24],[26],[34]	105,785	[21],[25],[28],[37]
Amortized Cost		$ 6,681	[18],[24],[26],[34]	$ 6,681	[21],[25],[28],[37]
Fair Value		$ 2,202	[3],[18],[24],[26],[34]	$ 1,661	[4],[21],[25],[28],[37]
Investment, Identifier [Axis]: GasLog Ltd., Energy—Midstream
Variable rate (percent)	[9],[18],[20]	7.80%
Rate (percent)	[10],[21],[23]			7.80%
Principal  Amount		$ 13,951	[14],[18],[20]	$ 13,951	[15],[21],[23]
Amortized Cost		13,877	[18],[20]	13,874	[21],[23]
Fair Value		$ 13,357	[3],[18],[20]	$ 13,510	[4],[21],[23]
Investment, Identifier [Axis]: Global Jet Capital Holdings, LP, Preferred Equity, Commercial & Professional Services 1
Number of Shares		2,785,562	[7],[18],[24]	2,785,562	[21],[25]
Amortized Cost		$ 2,786	[7],[18],[24]	$ 2,786	[21],[25]
Fair Value		$ 0	[3],[7],[18],[24]	$ 0	[4],[21],[25]
Investment, Identifier [Axis]: Global Jet Capital Holdings, LP, Preferred Equity, Commercial & Professional Services 2
Rate (percent)	[7],[9],[18],[24],[30]	9%
PIK Rate (percent)	[10],[21],[25],[31]			9%
Number of Shares		20,414	[7],[18],[24],[30]	19,965	[21],[25],[31]
Amortized Cost		$ 12,493	[7],[18],[24],[30]	$ 12,493	[21],[25],[31]
Fair Value		$ 10,360	[3],[7],[18],[24],[30]	$ 10,357	[4],[21],[25],[31]
Investment, Identifier [Axis]: Global Jet Capital Holdings, LP, Preferred Equity, Commercial & Professional Services 2 \| Maximum
PIK Rate (percent)		9%	[7],[9],[18],[24],[30]	9%	[10],[21],[25],[31]
Investment, Identifier [Axis]: Global Tel Link Corp., Technology Hardware & Equipment
Variable rate (percent)	[9],[11],[32]	4.25%
Principal  Amount	[11],[14],[32]	$ 14,031
Amortized Cost	[11],[32]	13,599
Fair Value	[3],[11],[32]	$ 13,685
Investment, Identifier [Axis]: Gold Rush Amusements, Inc., Consumer Services
Variable rate (percent)		7.50%	[9],[11],[18]	7.50%	[10],[12],[21]
Floor Rate (percent)		2%	[9],[11],[18]	2%	[10],[12],[21]
Principal  Amount		$ 30,596	[11],[14],[18]	$ 30,673	[12],[15],[21]
Amortized Cost		30,023	[11],[18]	30,079	[12],[21]
Fair Value		$ 30,328	[3],[11],[18]	$ 30,059	[4],[12],[21]
Investment, Identifier [Axis]: Goodnight Water Solutions, LLC, Energy—Midstream
Variable rate (percent)		7%	[9],[11],[18]	7%	[10],[12],[21]
Floor Rate (percent)		0.50%	[9],[11],[18]	0.50%	[10],[12],[21]
Principal  Amount		$ 14,328	[11],[14],[18]	$ 14,516	[12],[15],[21]
Amortized Cost		14,141	[11],[18]	14,326	[12],[21]
Fair Value		$ 14,238	[3],[11],[18]	$ 14,379	[4],[12],[21]
Investment, Identifier [Axis]: Guardian US Holdco, LLC, Financial Services
Variable rate (percent)		3.50%	[9],[11]	4%	[10],[12]
Floor Rate (percent)		0.50%	[9],[11]	0.50%	[10],[12]
Principal  Amount		$ 24,863	[11],[14]	$ 19,925	[12],[15]
Amortized Cost		24,891	[11]	19,922	[12]
Fair Value		$ 24,959	[3],[11]	$ 20,008	[4],[12]
Investment, Identifier [Axis]: Guitar Center, Inc., Consumer Discretionary Distribution & Retail
Rate (percent)		8.50%	[9],[11]	8.50%	[10],[12]
Principal  Amount		$ 23,568	[11],[14]	$ 20,000	[12],[15]
Amortized Cost		21,346	[11]	17,987	[12]
Fair Value		20,819	[3],[11]	17,473	[4],[12]
Investment, Identifier [Axis]: Harvest Oil & Gas Corp., Common Equity
Fair Value		$ 344		$ 271		810
Investment, Identifier [Axis]: Harvest Oil & Gas Corp., Common Equity, Energy—Upstream
Number of Shares		135,062	[18],[24],[34]	135,062	[25],[37]
Amortized Cost		$ 14,418	[18],[24],[34]	$ 14,418	[25],[37]
Fair Value		$ 344	[3],[18],[24],[34]	$ 271	[4],[25],[37]
Investment, Identifier [Axis]: Knowlton Development Corporation Inc., Household & Personal Products
Variable rate (percent)		5%	[9],[11]	5%	[10],[12]
Principal  Amount		$ 26,000	[11],[14]	$ 21,000	[12],[15]
Amortized Cost		25,352	[11]	20,370	[12]
Fair Value		$ 26,081	[3],[11]	$ 20,858	[4],[12]
Investment, Identifier [Axis]: LABL, Inc., Commercial & Professional Services
Variable rate (percent)	[9],[11]	5%
Floor Rate (percent)	[9],[11]	0.50%
Principal  Amount	[11],[14]	$ 24,801
Amortized Cost	[11]	24,129
Fair Value	[3],[11]	$ 24,343
Investment, Identifier [Axis]: LABL, Inc., Commerical & Professional Services
Variable rate (percent)	[10],[12]			5%
Floor Rate (percent)	[10],[12]			0.50%
Principal  Amount	[12],[15]			$ 19,864
Amortized Cost	[12]			19,335
Fair Value	[4],[12]			$ 19,106
Investment, Identifier [Axis]: LaserShip, Inc., Transportation
Variable rate (percent)	[9],[11]	4.50%
Floor Rate (percent)	[9],[11]	0.80%
Principal  Amount	[11],[14]	$ 6,982
Amortized Cost	[11]	6,613
Fair Value	[3],[11]	$ 6,523
Investment, Identifier [Axis]: Learning Care Group No. 2 Inc., Consumer Services
Variable rate (percent)		4.75%	[9],[11]	4.75%	[10],[12]
Floor Rate (percent)		0.50%	[9],[11]	0.50%	[10],[12]
Principal  Amount		$ 21,895	[11],[14]	$ 19,950	[12],[15]
Amortized Cost		22,027	[11]	20,070	[12]
Fair Value		$ 21,959	[3],[11]	20,100	[4],[12]
Investment, Identifier [Axis]: Limetree Bay Energy, LLC, Class A Units
Fair Value				$ 0		1,885
Investment, Identifier [Axis]: MBS Services Holdings, LLC, A-3 Units, Commercial & Professional Services
Number of Shares	[18],[24],[26]	522,382
Amortized Cost	[18],[24],[26]	$ 522
Fair Value	[3],[18],[24],[26]	$ 0
Investment, Identifier [Axis]: MBS Services Holdings, LLC, Commercial & Professional Services
Rate (percent)	[9],[18]	15%
Principal  Amount	[14],[18]	$ 28,622
Amortized Cost	[18]	27,569
Fair Value	[3],[18]	$ 28,049
Investment, Identifier [Axis]: MBS Services Holdings, LLC, Commercial & Professional Services \| Maximum
PIK Rate (percent)	[9],[18]	15%
Investment, Identifier [Axis]: Maverick Natural Resources, LLC, Common Equity, Energy—Upstream
Number of Shares		503,176	[18],[26]	503,176	[21],[25],[28]
Amortized Cost		$ 93,044	[18],[26]	$ 93,044	[21],[25],[28]
Fair Value		$ 78,546	[3],[18],[26]	$ 164,040	[4],[21],[25],[28]
Investment, Identifier [Axis]: Mavis Tire Express Services TopCo, L.P., Consumer Discretionary Distribution & Retail
Variable rate (percent)		3.75%	[9],[11]	4%	[10],[12]
Floor Rate (percent)		0.80%	[9],[11]	0.80%	[10],[12]
Principal  Amount		$ 17,349	[11],[14]	$ 19,893	[12],[15]
Amortized Cost		17,368	[11]	19,797	[12]
Fair Value		$ 17,399	[3],[11]	$ 19,955	[4],[12]
Investment, Identifier [Axis]: NGL Energy Partners, LP, Preferred Equity, Energy—Midstream
Rate (percent)		14.20%	[7],[9],[11],[18],[20],[30]	14.20%	[10],[12],[21],[23],[25],[31]
Number of Shares		156,250	[7],[11],[18],[20],[30]	156,250	[12],[21],[23],[25],[31]
Amortized Cost		$ 157,679	[7],[11],[18],[20],[30]	$ 157,633	[12],[21],[23],[25],[31]
Fair Value		$ 222,338	[3],[7],[11],[18],[20],[30]	$ 141,141	[4],[12],[21],[23],[25],[31]
Investment, Identifier [Axis]: NGL Energy Partners, LP, Warrants (Par), Strike, Energy—Midstream
Number of Shares	[18],[20],[24]	2,187,500
Amortized Cost	[18],[20],[24]	$ 3,083
Fair Value	[3],[18],[20],[24]	$ 2,472
Strike price (in dollars per share)	[1],[18],[20],[24]	$ 14.54
Investment, Identifier [Axis]: NGL Energy Partners, LP, Warrants (Par), Strike, Energy—Midstream 2
Number of Shares	[18],[20],[24]	546,880
Amortized Cost	[18],[20],[24]	$ 630
Fair Value	[3],[18],[20],[24]	$ 589
Strike price (in dollars per share)	[1],[18],[20],[24]	$ 13.56
Investment, Identifier [Axis]: NGL Energy Partners, LP, Warrants (Par), Strike: $13.56, Energy—Midstream
Number of Shares	[21],[23],[25]			546,880
Amortized Cost	[21],[23],[25]			$ 630
Fair Value	[4],[21],[23],[25]			$ 621
Strike price (in dollars per share)	[2],[21],[23],[25]			$ 13.56
Investment, Identifier [Axis]: NGL Energy Partners, LP, Warrants (Par), Strike: $14.54, Energy—Midstream
Number of Shares	[21],[23],[25]			2,187,500
Amortized Cost	[21],[23],[25]			$ 3,083
Fair Value	[4],[21],[23],[25]			$ 2,682
Strike price (in dollars per share)	[2],[21],[23],[25]			$ 14.54
Investment, Identifier [Axis]: NGL Energy Partners, LP, Warrants (Premium), Strike, Energy—Midstream 1
Number of Shares	[18],[20],[24]	3,125,000
Amortized Cost	[18],[20],[24]	$ 2,623
Fair Value	[3],[18],[20],[24]	$ 2,808
Strike price (in dollars per share)	[1],[18],[20],[24]	$ 17.45
Investment, Identifier [Axis]: NGL Energy Partners, LP, Warrants (Premium), Strike, Energy—Midstream 2
Number of Shares	[18],[20],[24]	781,250
Amortized Cost	[18],[20],[24]	$ 576
Fair Value	[3],[18],[20],[24]	$ 660
Strike price (in dollars per share)	[1],[18],[20],[24]	$ 16.27
Investment, Identifier [Axis]: NGL Energy Partners, LP, Warrants (Premium), Strike: $16.27, Energy—Midstream
Number of Shares	[21],[23],[25]			781,250
Amortized Cost	[21],[23],[25]			$ 576
Fair Value	[4],[21],[23],[25]			$ 735
Strike price (in dollars per share)	[2],[21],[23],[25]			$ 16.27
Investment, Identifier [Axis]: NGL Energy Partners, LP, Warrants (Premium), Strike: $17.45, Energy—Midstream
Number of Shares	[21],[23],[25]			3,125,000
Amortized Cost	[21],[23],[25]			$ 2,623
Fair Value	[4],[21],[23],[25]			$ 3,083
Strike price (in dollars per share)	[2],[21],[23],[25]			$ 17.45
Investment, Identifier [Axis]: Navios Logistics Finance, Inc., Transportation
Rate (percent)		10.80%	[9],[11],[20]	10.80%	[10],[12],[23]
Principal  Amount		$ 25,000	[11],[14],[20]	$ 20,000	[12],[15],[23]
Amortized Cost		24,679	[11],[20]	19,680	[12],[23]
Fair Value		$ 25,013	[3],[11],[20]	$ 19,772	[4],[12],[23]
Investment, Identifier [Axis]: Nephron Pharmaceuticals Corp., Pharmaceuticals, Biotechnology & Life Sciences
Variable rate (percent)		9%	[9],[18]	9%	[10],[21]
Floor Rate (percent)		1.50%	[9],[18]	1.50%	[10],[21]
Principal  Amount		$ 19,925	[14],[18]	$ 20,000	[15],[21]
Amortized Cost		19,434	[18]	19,400	[21]
Fair Value		$ 19,352	[3],[18]	19,300	[4],[21]
Investment, Identifier [Axis]: Osaic Holdings, Inc., Financial Services
Variable rate (percent)	[9],[11],[32]	4.50%
Principal  Amount	[11],[14],[32]	$ 4,988
Amortized Cost	[11],[32]	4,988
Fair Value	[3],[11],[32]	5,013
Investment, Identifier [Axis]: Permian Production Holdings, LLC
Fair Value		4,050		4,816		4,767
Investment, Identifier [Axis]: Permian Production Holdings, LLC, Common Equity
Fair Value		$ 1,043		$ 748		11,420
Investment, Identifier [Axis]: Permian Production Holdings, LLC, Common Equity, Energy—Upstream
Number of Shares		1,968,861	[18],[24],[26],[34]	1,968,861	[21],[25],[28],[37]
Amortized Cost		$ 5	[18],[24],[26],[34]	$ 5	[21],[25],[28],[37]
Fair Value		$ 1,043	[3],[18],[24],[26],[34]	$ 748	[4],[21],[25],[28],[37]
Investment, Identifier [Axis]: Permian Production Holdings, LLC, Energy—Upstream
Rate (percent)		7%	[9],[18],[34]	7%	[10],[21],[37]
PIK Rate (percent)		2%	[9],[18],[34]	2%	[10],[21],[37]
Principal  Amount		$ 4,060	[14],[18],[34]	$ 4,864	[15],[21],[37]
Amortized Cost		3,798	[18],[34]	4,497	[21],[37]
Fair Value		$ 4,050	[3],[18],[34]	$ 4,816	[4],[21],[37]
Investment, Identifier [Axis]: Permian Production Holdings, LLC, Energy—Upstream \| Maximum
PIK Rate (percent)		2%	[9],[18],[34]	2%	[10],[21],[37]
Investment, Identifier [Axis]: Phoenix Guarantor Inc., Financial Services
Variable rate (percent)	[10],[12],[13]			3.50%
Principal  Amount	[12],[13],[15]			$ 19,923
Amortized Cost	[12],[13]			19,891
Fair Value	[4],[12],[13]			$ 19,951
Investment, Identifier [Axis]: Plainfield Renewable Energy Holdings LLC, Energy—Power 2
PIK Rate (percent)	[9],[18],[24],[30]	10%
Principal  Amount	[14],[18],[24],[30]	$ 4,218
Amortized Cost	[18],[24],[30]	3,827
Fair Value	[3],[18],[24],[30]	$ 0
Investment, Identifier [Axis]: Plainfield Renewable Energy Holdings LLC, Energy—Power 2 \| Maximum
PIK Rate (percent)	[9],[18],[24],[30]	10%
Investment, Identifier [Axis]: Plainfield Renewable Energy Holdings LLC, Energy—Power 1
Rate (percent)		6%	[9],[18],[24],[30]	6%	[10],[21],[25],[31]
PIK Rate (percent)		9.50%	[9],[18],[24],[30]	9.50%	[10],[21],[25],[31]
Principal  Amount		$ 13,936	[14],[18],[24],[30]	$ 13,297	[15],[21],[25],[31]
Amortized Cost		11,926	[18],[24],[30]	12,329	[21],[25],[31]
Fair Value		$ 4,592	[3],[18],[24],[30]	$ 7,473	[4],[21],[25],[31]
Investment, Identifier [Axis]: Plainfield Renewable Energy Holdings LLC, Energy—Power 1 \| Maximum
PIK Rate (percent)		9.50%	[9],[18],[24],[30]	9.50%	[10],[21],[25],[31]
Investment, Identifier [Axis]: Plainfield Renewable Energy Holdings LLC, Energy—Power 2
PIK Rate (percent)	[10],[21],[25],[31]			10%
Principal  Amount	[15],[21],[25],[31]			$ 4,015
Amortized Cost	[21],[25],[31]			3,827
Fair Value	[4],[21],[25],[31]			$ 0
Investment, Identifier [Axis]: Plainfield Renewable Energy Holdings LLC, Energy—Power 2 \| Maximum
PIK Rate (percent)	[10],[21],[25],[31]			10%
Investment, Identifier [Axis]: Plainfield Renewable Energy Holdings LLC, Letter of Credit, Energy—Power
Rate (percent)		10%	[9],[16],[18]	10%	[10],[17],[21]
Principal  Amount		$ 2,709	[14],[16],[18]	$ 2,709	[15],[17],[21]
Amortized Cost		2,709	[16],[18]	2,709	[17],[21]
Fair Value		$ 0	[3],[16],[18]	$ 0	[4],[17],[21]
Investment, Identifier [Axis]: Pretium PKG Holdings, Inc., Materials
Variable rate (percent)		2.50%	[9],[11]	5%	[10],[12]
PIK Rate (percent)	[9],[11]	2.50%
Floor Rate (percent)		1%	[9],[11]	1%	[10],[12]
Principal  Amount		$ 32,378	[11],[14]	$ 30,118	[12],[15]
Amortized Cost		31,871	[11]	29,634	[12]
Fair Value		$ 32,883	[3],[11]	$ 29,591	[4],[12]
Investment, Identifier [Axis]: Pretium PKG Holdings, Inc., Materials \| Maximum
PIK Rate (percent)	[9],[11]	2.50%
Investment, Identifier [Axis]: Pro Mach Group, Inc., Capital Goods
Variable rate (percent)		3.75%	[9],[11]	4%	[10],[12]
Floor Rate (percent)		1%	[9],[11]	1%	[10],[12]
Principal  Amount		$ 17,424	[11],[14]	$ 19,924	[12],[15]
Amortized Cost		17,478	[11]	19,979	[12]
Fair Value		$ 17,506	[3],[11]	$ 20,007	[4],[12]
Investment, Identifier [Axis]: Proampac PG Borrower LLC, Materials
Variable rate (percent)		4.50%	[9],[11]	4.50%	[10],[12]
Floor Rate (percent)		0.80%	[9],[11]	0.80%	[10],[12]
Principal  Amount		$ 22,942	[11],[14]	$ 20,000	[12],[15]
Amortized Cost		22,955	[11]	19,994	[12]
Fair Value		$ 23,023	[3],[11]	$ 20,062	[4],[12]
Investment, Identifier [Axis]: RealTruck Group, Inc., Automobiles & Components
Variable rate (percent)	[9],[11]	3.50%
Floor Rate (percent)	[9],[11]	0.80%
Principal  Amount	[11],[14]	$ 24,885
Amortized Cost	[11]	24,066
Fair Value	[3],[11]	$ 24,729
Investment, Identifier [Axis]: Realtruck Group, Inc., Automobiles & Components
Variable rate (percent)	[10],[12],[13]			3.50%
Floor Rate (percent)	[10],[12],[13]			0.80%
Principal  Amount	[12],[13],[15]			$ 19,956
Amortized Cost	[12],[13]			19,117
Fair Value	[4],[12],[13]			19,740
Investment, Identifier [Axis]: Ridgeback Resources Inc., Common Equity
Fair Value				$ 0		41,851
Investment, Identifier [Axis]: Ryan, LLC, Commercial & Professional Services 1
Variable rate (percent)	[9],[11]	4.50%
Floor Rate (percent)	[9],[11]	0.50%
Principal  Amount	[11],[14]	$ 9,844
Amortized Cost	[11]	9,868
Fair Value	[3],[11]	$ 9,905
Investment, Identifier [Axis]: Ryan, LLC, Commercial & Professional Services 2
Variable rate (percent)	[9],[16]	4.50%
Floor Rate (percent)	[9],[16]	0.50%
Principal  Amount	[14],[16]	$ 1,036
Amortized Cost	[16]	1,036
Fair Value	[3],[16]	$ 1,043
Investment, Identifier [Axis]: Ryan, LLC, Commerical & Professional Services 1
Variable rate (percent)	[10],[12],[13]			4.50%
Floor Rate (percent)	[10],[12],[13]			0.50%
Principal  Amount	[12],[13],[15]			$ 9,844
Amortized Cost	[12],[13]			9,868
Fair Value	[4],[12],[13]			$ 9,890
Investment, Identifier [Axis]: Ryan, LLC, Commerical & Professional Services 2
Variable rate (percent)	[10],[13],[17]			4.50%
Floor Rate (percent)	[10],[13],[17]			0.50%
Principal  Amount	[13],[15],[17]			$ 1,036
Amortized Cost	[13],[17]			1,039
Fair Value	[4],[13],[17]			$ 1,041
Investment, Identifier [Axis]: SRS Distribution Inc., Capital Goods
Variable rate (percent)		3.50%	[9],[11]	3.50%	[10],[12],[13]
Floor Rate (percent)		0.50%	[9],[11]	0.50%	[10],[12],[13]
Principal  Amount		$ 24,860	[11],[14]	$ 19,924	[12],[13],[15]
Amortized Cost		24,705	[11]	19,729	[12],[13]
Fair Value		$ 25,060	[3],[11]	$ 19,982	[4],[12],[13]
Investment, Identifier [Axis]: ST EIP Holdings Inc., Energy—Midstream
Rate (percent)		6.30%	[9],[11],[18]	6.30%	[10],[12],[21]
Principal  Amount		$ 10,311	[11],[14],[18]	$ 10,365	[12],[15],[21]
Amortized Cost		9,914	[11],[18]	9,951	[12],[21]
Fair Value		9,771	[3],[11],[18]	9,874	[4],[12],[21]
Investment, Identifier [Axis]: Sustainable Infrastructure Investments, LLC
Fair Value				39,427		51,098
Investment, Identifier [Axis]: Sustainable Infrastructure Investments, LLC 2
Fair Value		40,830		39,427
Investment, Identifier [Axis]: Sustainable Infrastructure Investments, LLC, Energy—Power
Principal  Amount		60,603	[14],[18],[20],[27]	60,603	[21],[23],[29]
Amortized Cost		43,150	[18],[20],[27]	43,150	[21],[23],[29]
Fair Value		$ 40,830	[3],[18],[20],[27]	$ 39,427	[4],[21],[23],[29]
Investment, Identifier [Axis]: TKC Holdings, Inc., Consumer Staples Distribution & Retail
Variable rate (percent)		5.50%	[9],[11]	5.50%	[10],[12]
Floor Rate (percent)		1%	[9],[11]	1%	[10],[12]
Principal  Amount		$ 24,536	[11],[14]	$ 19,650	[12],[15]
Amortized Cost		23,460	[11]	18,681	[12]
Fair Value		24,337	[3],[11]	18,830	[4],[12]
Investment, Identifier [Axis]: Telpico, LLC, Common Equity
Fair Value		$ 0		$ 0		0
Investment, Identifier [Axis]: Telpico, LLC, Common Equity, Energy—Upstream
Number of Shares		50	[18],[24],[26],[34]	50	[21],[25],[28],[37]
Amortized Cost		$ 0	[18],[24],[26],[34]	$ 0	[21],[25],[28],[37]
Fair Value		$ 0	[3],[18],[24],[26],[34]	$ 0	[4],[21],[25],[28],[37]
Investment, Identifier [Axis]: Tenrgys, LLC, Common Equity, Energy—Upstream
Number of Shares		50	[18],[24],[26]	50	[21],[25],[28]
Amortized Cost		$ 7,571	[18],[24],[26]	$ 7,571	[21],[25],[28]
Fair Value		$ 1,245	[3],[18],[24],[26]	$ 4,418	[4],[21],[25],[28]
Investment, Identifier [Axis]: Tenrgys, LLC, Energy—Upstream
Variable rate (percent)		7.50%	[9],[11],[18]	7.50%	[10],[12],[21]
Floor Rate (percent)		1%	[9],[11],[18]	1%	[10],[12],[21]
Principal  Amount		$ 20,537	[11],[14],[18]	$ 20,537	[12],[15],[21]
Amortized Cost		20,537	[11],[18]	20,537	[12],[21]
Fair Value		$ 20,306	[3],[11],[18]	$ 19,998	[4],[12],[21]
Investment, Identifier [Axis]: Tenrgys, LLC, Energy—Upstream \| Maximum
PIK Rate (percent)		9.50%	[9],[11],[18]	9.50%	[10],[12],[21]
Investment, Identifier [Axis]: TruGreen, LP, Commercial & Professional Services
Variable rate (percent)		4%	[9],[11]	4%	[10],[12]
Floor Rate (percent)		0.80%	[9],[11]	0.80%	[10],[12]
Principal  Amount		$ 24,846	[11],[14]	$ 19,910	[12],[15]
Amortized Cost		23,463	[11]	18,614	[12]
Fair Value		24,230	[3],[11]	19,268	[4],[12]
Investment, Identifier [Axis]: U.S. Treasury Bills, U.S. Treasury 1
Principal  Amount	[38],[39]	100,000
Amortized Cost	[38],[39]	99,826
Fair Value	[3],[38],[39]	99,884
Investment, Identifier [Axis]: U.S. Treasury Bills, U.S. Treasury 2
Principal  Amount	[38],[39]	27,000
Amortized Cost	[38],[39]	26,937
Fair Value	[3],[38],[39]	$ 26,941
Investment, Identifier [Axis]: U.S. Treasury Bills, U.S. Treasury Bills
Principal  Amount	[40]			21,000
Amortized Cost	[40]			20,994
Fair Value	[4],[40]			$ 21,000
Investment, Identifier [Axis]: USA Compression Partners, LP, Preferred Equity, Energy—Midstream
Rate (percent)		9.80%	[7],[9],[11],[18],[20]	9.80%	[10],[12],[21],[23]
Number of Shares		72,989	[7],[11],[18],[20]	79,336	[12],[21],[23]
Amortized Cost		$ 71,940	[7],[11],[18],[20]	$ 78,091	[12],[21],[23]
Fair Value		$ 86,324	[3],[7],[11],[18],[20]	98,333	[4],[12],[21],[23]
Investment, Identifier [Axis]: WMK, LLC, Consumer Discretionary Distribution & Retail 1
Variable rate (percent)	[9],[11],[18]	6.50%
Floor Rate (percent)	[9],[11],[18]	3%
Principal  Amount	[11],[14],[18]	$ 29,833
Amortized Cost	[11],[18]	28,839
Fair Value	[3],[11],[18]	$ 28,956
Investment, Identifier [Axis]: WMK, LLC, Consumer Discretionary Distribution & Retail 2
Variable rate (percent)	[9],[16],[18]	6.50%
Floor Rate (percent)	[9],[16],[18]	3%
Principal  Amount	[14],[16],[18]	$ 5,167
Amortized Cost	[16],[18]	5,167
Fair Value	[3],[16],[18]	5,015
Investment, Identifier [Axis]: Warren Resources, Inc.
Fair Value		23,883		23,823		23,584
Investment, Identifier [Axis]: Warren Resources, Inc., Common Equity
Fair Value		$ 14,417		$ 15,566		$ 36,982
Investment, Identifier [Axis]: Warren Resources, Inc., Common Equity, Energy—Upstream
Number of Shares		4,415,749	[18],[24],[27]	4,415,749	[21],[25],[29]
Amortized Cost		$ 20,881	[18],[24],[27]	$ 20,754	[21],[25],[29]
Fair Value		$ 14,417	[3],[18],[24],[27]	$ 15,566	[4],[21],[25],[29]
Investment, Identifier [Axis]: Warren Resources, Inc., Energy—Upstream
Variable rate (percent)		9%	[9],[11],[18],[27]	9%	[10],[12],[21],[29]
PIK Rate (percent)		1%	[9],[11],[18],[27]	1%	[10],[12],[21],[29]
Floor Rate (percent)		1%	[9],[11],[18],[27]	1%	[10],[12],[21],[29]
Principal  Amount		$ 23,883	[11],[14],[18],[27]	$ 23,823	[12],[15],[21],[29]
Amortized Cost		23,883	[11],[18],[27]	23,823	[12],[21],[29]
Fair Value		$ 23,883	[3],[11],[18],[27]	$ 23,823	[4],[12],[21],[29]
Investment, Identifier [Axis]: Warren Resources, Inc., Energy—Upstream \| Maximum
PIK Rate (percent)		1%	[9],[11],[18],[27]	1%	[10],[12],[21],[29]
Investment, Identifier [Axis]: Wattbridge Inc., Energy—Power
Variable rate (percent)		9.85%	[9],[11],[18]	9.85%	[10],[12],[21]
Floor Rate (percent)		1.80%	[9],[11],[18]	1.80%	[10],[12],[21]
Principal  Amount		$ 42,938	[11],[14],[18]	$ 42,938	[12],[15],[21]
Amortized Cost		42,938	[11],[18]	42,938	[12],[21]
Fair Value		$ 41,866	[3],[11],[18]	$ 41,882	[4],[12],[21]
Investment, Identifier [Axis]: Weber-Stephen Products LLC, Consumer Durables & Apparel
Variable rate (percent)	[9],[11],[32]	3.25%
Floor Rate (percent)	[9],[11],[32]	0.80%
Principal  Amount	[11],[14],[32]	$ 26,285
Amortized Cost	[11],[32]	24,014
Fair Value	[3],[11],[32]	$ 24,404
Net Senior Secured Loans—First Lien
Percent of net assets		61%	[1]	52.90%	[2]
Amortized Cost		$ 1,031,295	[1]	$ 878,013	[2]
Fair Value		962,663	[1],[3]	825,158	[2],[4]
Total Senior Secured Loans—First Lien
Amortized Cost		1,046,291	[1]	889,245	[2]
Fair Value		977,659	[1],[3]	836,390	[2],[4]
Unfunded Loan Commitments
Amortized Cost		(14,996)	[1]	(11,232)	[2]
Fair Value		$ (14,996)	[1],[3]	$ (11,232)	[2],[4]
Net Senior Secured Loans—Second Lien
Percent of net assets		5.20%	[1]	3.50%	[2]
Amortized Cost		$ 81,646	[1]	$ 55,064
Fair Value		$ 81,936	[1],[3]	54,424
Total Senior Secured Loans—Second Lien
Amortized Cost	[2]			55,064
Fair Value	[2],[4]			$ 54,424
Senior Secured Bonds
Percent of net assets		6.20%	[1]	5.40%	[2]
Amortized Cost		$ 96,035	[1]	$ 82,793
Fair Value		$ 98,436	[1],[3]	$ 84,468	[4]
Asset Based Finance
Percent of net assets	[1]	1.30%
Amortized Cost	[1]	$ 20,329
Fair Value	[1],[3]	$ 20,329
Preferred Equity
Percent of net assets		20.60%	[1],[7]	16.60%	[2],[36]
Amortized Cost		$ 246,345	[1],[7]	$ 252,450	[2],[36]
Fair Value		$ 324,731	[1],[3],[7]	$ 259,990	[2],[4],[36]
Sustainable Infrastructure Investments, LLC
Percent of net assets		2.60%	[1]	2.50%	[2]
Amortized Cost		$ 43,150	[1]	$ 43,150	[2]
Fair Value		$ 40,830	[1],[3]	$ 39,427	[2],[4]
Equity/Other
Percent of net assets		9.20%	[1]	15.30%	[2]
Amortized Cost		$ 211,451	[1]	$ 211,461	[2]
Fair Value		$ 145,522	[1],[3]	$ 238,729	[2],[4]
Short-Term Investments
Percent of net assets		8%	[1]	1.30%	[2]
Amortized Cost		$ 126,763	[1]	$ 20,994	[2]
Fair Value		$ 126,825	[1],[3]	$ 21,000	[2],[4]
Cash and Cash Equivalents
Percent of net assets		11.80%	[1],[7]	31.10%	[2],[8]

[1]Security may be an obligation of one or more entities affiliated with the named company.[2]Security may be an obligation of one or more entities affiliated with the named company.[3]See Note 8 for additional information regarding the fair value of the Company’s financial instruments.[4]See Note 8 for additional information regarding the fair value of the Company’s financial instruments.[5]Includes the effect of swap contracts.[6]Includes the effect of swap contracts.[7]Includes $59,698 held in Allspring Government Money Market Fund with a 7-day yield of 5.2% as of March 31, 2024.[8]Includes $23,098 held in Allspring Government Money Market Fund with a 7-day yield of 5.3% as of December 31, 2023.[9]Certain variable rate securities in the Company’s portfolio bear interest at a rate determined by a publicly disclosed base rate plus a basis point spread. As of March 31, 2024, the one-month and three-month Secured Overnight Financing Rate, or SOFR, or S, was 5.33% and 5.30%, respectively, and the Overnight Bank Funding Rate, or OBFR, was 5.33%. SOFR based contracts may include a credit spread adjustment that is charged in addition to the base rate and basis point spread. PIK means paid-in-kind. PIK income accruals may be adjusted based on the fair value of the underlying investment. Variable rate securities with no floor rate use the respective benchmark rate in all cases.[10]Certain variable rate securities in the Company’s portfolio bear interest at a rate determined by a publicly disclosed base rate plus a basis point spread. As of December 31, 2023, the one-month and three-month Secured Overnight Financing Rate, or SOFR, or S, was 5.35% and 5.33%, respectively, and the Overnight Bank Funding Rate, or OBFR, was 5.32%. SOFR based contracts may include a credit spread adjustment that is charged in addition to the base rate and basis point spread. PIK means paid-in-kind. PIK income accruals may be adjusted based on the fair value of the underlying investment. Variable rate securities with no floor rate use the respective benchmark rate in all cases.[11]Security or portion thereof held within FSSL Finance BB AssetCo LLC, a wholly-owned subsidiary of the Company, and is pledged as collateral supporting the obligations outstanding under the repurchase facility with Barclays Bank PLC (see Note 9).[12]Security or portion thereof held within FSSL Finance BB AssetCo LLC, a wholly-owned subsidiary of the Company, and is pledged as collateral supporting the obligations outstanding under the repurchase facility with Barclays Bank PLC (see Note 9).[13]Security or portion thereof unsettled as of December 31, 2023.[14]Denominated in U.S. dollars, unless otherwise noted.[15]Denominated in U.S. dollars, unless otherwise noted.[16]Security is an unfunded commitment. The stated rate reflects the spread disclosed at the time of commitment and may not indicate the actual rate received upon funding.[17]Security is an unfunded commitment. The stated rate reflects the spread disclosed at the time of commitment and may not indicate the actual rate received upon funding.[18]Security is classified as Level 3 in the Company’s fair value hierarchy (see Note 8).[19]Security or portion thereof held within FS Power Investments II, LLC, a wholly-owned subsidiary of the Company.[20]The investment is not a qualifying asset under the Investment Company Act of 1940, as amended, or the 1940 Act. A business development company may not acquire any asset other than a qualifying asset, unless, at the time the acquisition is made, qualifying assets represent at least 70% of the business development company’s total assets. As of March 31, 2024, 75.7% of the Company’s total assets represented qualifying assets.[21]Security is classified as Level 3 in the Company’s fair value hierarchy (see Note 8).[22]Security or portion thereof held within FS Power Investments II, LLC, a wholly-owned subsidiary of the Company.[23]The investment is not a qualifying asset under the Investment Company Act of 1940, as amended, or the 1940 Act. A business development company may not acquire any asset other than a qualifying asset, unless, at the time the acquisition is made, qualifying assets represent at least 70% of the business development company’s total assets. As of December 31, 2023, 80.8% of the Company’s total assets represented qualifying assets.[24]Security is non-income producing.[25]Security is non-income producing.[26]Security held within FSEP Investments, Inc., a wholly-owned subsidiary of the Company.[27]Under the 1940 Act, the Company generally is deemed to “control” a portfolio company if it owns more than 25% of the portfolio company’s voting securities or it has the power to exercise control over the management or policies of such portfolio company. As of March 31, 2024, the Company held investments in portfolio companies of which it is deemed to be an “affiliated person” of and deemed to “control.” The following table presents certain information with respect to investments in portfolio companies of which the Company was deemed to be an affiliated person and deemed to control as of March 31, 2024: Portfolio Company Fair Value at December 31, 2023 Gross Additions (1) Gross Reductions (2) Net Realized Gain (Loss) Net Change in Unrealized Appreciation (Depreciation) Fair Value at March 31, 2024 Interest Income (3) PIK Income (3) Senior Secured Loans—First Lien Allied Wireline Services, LLC $ 22,200 $ — $ — $ — $ (14,965) $ 7,235 $ — $ — Warren Resources, Inc. 23,823 60 — — — 23,883 881 60 Sustainable Infrastructure Investments, LLC Sustainable Infrastructure Investments, LLC 39,427 — — — 1,403 40,830 — — Equity/Other Allied Wireline Services, LLC, Common Equity — — — — — — — — Allied Wireline Services, LLC, Warrants — — — — — — — — Warren Resources, Inc., Common Equity 15,566 127 — — (1,276) 14,417 — — $ 101,016 $ 187 $ — $ — $ (14,838) $ 86,365 $ 881 $ 60 _____________ (1) Gross additions may include increases in the cost basis of investments resulting from new portfolio investments, PIK interest, the amortization of unearned income, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company into this category from a different category. (2) Gross reductions may include decreases in the cost basis of investments resulting from principal collections related to investment repayments or sales, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company out of this category into a different category. (3) Interest and PIK income presented for the three months ended March 31, 2024. Portfolio Company Fair Value at December 31, 2022 Gross Additions (1) Gross Reductions (2) Net Realized Gain (Loss) Net Change in Unrealized Appreciation (Depreciation) Fair Value at December 31, 2023 Interest Income (3) PIK Income (3) Dividend Income (3) Senior Secured Loans—First Lien Allied Downhole Technologies, LLC $ 8,436 $ 138 $ (8,574) $ — $ — $ — $ 256 $ 139 $ — Allied Wireline Services, LLC 63,888 6,389 — — (48,077) 22,200 — 2,910 — Warren Resources, Inc. 23,584 239 — — — 23,823 3,464 179 — Sustainable Infrastructure Investments, LLC Sustainable Infrastructure Investments, LLC 51,098 — (11,364) — (307) 39,427 — — 8,324 Equity/Other Allied Wireline Services, LLC, Common Equity 10,463 — — — (10,463) — — — — Allied Wireline Services, LLC, Warrants — — — — — — — — — Warren Resources, Inc., Common Equity 36,982 — — — (21,416) 15,566 — — — $ 194,451 $ 6,766 $ (19,938) $ — $ (80,263) $ 101,016 $ 3,720 $ 3,228 $ 8,324 _____________ (1) Gross additions may include increases in the cost basis of investments resulting from new portfolio investments, PIK interest, the amortization of unearned income, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company into this category from a different category. (2) Gross reductions may include decreases in the cost basis of investments resulting from principal collections related to investment repayments or sales, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company out of this category into a different category. (3) Interest, PIK and dividend income presented for the year ended December 31, 2023. Portfolio Company Fair Value at December 31, 2023 Gross Additions (1) Gross Reductions (2) Net Realized Gain (Loss) Net Change in Unrealized Appreciation (Depreciation) Fair Value at March 31, 2024 Interest Income (3) PIK Income (3) Senior Secured Loans—First Lien Permian Production Holdings, LLC $ 4,816 $ 58 $ (828) $ 71 $ (67) $ 4,050 $ 160 $ 23 Asset Based Finance Bridge Street Warehouse CLO IV Ltd. — 20,329 — — — 20,329 — 329 Equity/Other GWP Midstream Holdco, LLC, Common Equity 1,661 — — — 541 2,202 — — Harvest Oil & Gas Corp., Common Equity 271 — — — 73 344 — — Permian Production Holdings, LLC, Common Equity 748 — — — 295 1,043 — — Telpico, LLC, Common Equity — — — — — — — — $ 7,496 $ 20,387 $ (828) $ 71 $ 842 $ 27,968 $ 160 $ 352 _____________ (1) Gross additions may include increases in the cost basis of investments resulting from new portfolio investments, PIK interest, the amortization of unearned income, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company into this category from a different category. (2) Gross reductions may include decreases in the cost basis of investments resulting from principal collections related to investment repayments or sales, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company out of this category into a different category. (3) Interest and PIK income presented for the three months ended March 31, 2024. Portfolio Company Fair Value at December 31, 2022 Gross Additions (1) Gross Reductions (2) Net Realized Gain (Loss) Net Change in Unrealized Appreciation (Depreciation) Fair Value at December 31, 2023 Interest Income (3) PIK Income (3) Senior Secured Loans—First Lien Permian Production Holdings, LLC $ 4,767 $ 231 $ — $ — $ (182) $ 4,816 $ 675 $ 97 Equity/Other GWP Midstream Holdco, LLC, Common Equity 5,044 — (3,112) 3,112 (3,383) 1,661 — — Harvest Oil & Gas Corp., Common Equity 810 — (641) — 102 271 — — Limetree Bay Energy, LLC, Class A Units 1,885 246 — (21,704) 19,573 — — — Permian Production Holdings, LLC, Common Equity 11,420 — — — (10,672) 748 — — Ridgeback Resources Inc., Common Equity 41,851 — (35,240) (11,359) 4,748 — — — Telpico, LLC, Common Equity — — — — — — — — $ 65,777 $ 477 $ (38,993) $ (29,951) $ 10,186 $ 7,496 $ 675 $ 97 _____________ (1) Gross additions may include increases in the cost basis of investments resulting from new portfolio investments, PIK interest, the amortization of unearned income, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company into this category from a different category. (2) Gross reductions may include decreases in the cost basis of investments resulting from principal collections related to investment repayments or sales, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company out of this category into a different category. (3) Interest and PIK income presented for the year ended December 31, 2023.

Unaudited Consolidated Schedu_2

Unaudited Consolidated Schedule of Investments (Parenthetical) - USD ($) $ in Thousands		3 Months Ended			12 Months Ended
		Mar. 31, 2024		Mar. 31, 2023	Dec. 31, 2023
Derivative [Line Items]
Qualifying assets, percent of total assets		75.70%			80.80%
Investments, at fair value		$ 1,801,272	[1],[2]		$ 1,523,196	[3],[4]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[3],[4]	1,523,196
Net Realized Gain (Loss)		4,190		$ (20,207)
Net Change in Unrealized Appreciation (Depreciation)		(35,013)		(30,473)
Fair Value, ending balance		1,801,272	[1],[2]		1,523,196	[3],[4]
Paid-in-kind interest income		1,648		4,502
Non-Controlled/Affiliated
Derivative [Line Items]
Investments, at fair value		27,968			7,496
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance		7,496		65,777	65,777
Gross Additions		20,387	[5]		477	[6]
Gross Reductions		(828)	[7]		(38,993)	[8]
Net Realized Gain (Loss)		71		(11,359)	(29,951)
Net Change in Unrealized Appreciation (Depreciation)		842		(2,561)	10,186
Fair Value, ending balance		27,968			7,496
Interest income		160	[9]		675	[10]
Paid-in-kind interest income		352	[9]	24	97	[10]
Controlled/affiliated
Derivative [Line Items]
Investments, at fair value		86,365			101,016
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance		101,016		194,451	194,451
Gross Additions		187	[11]		6,766	[12]
Gross Reductions		0	[13]		(19,938)	[14]
Net Realized Gain (Loss)		0			0
Net Change in Unrealized Appreciation (Depreciation)		(14,838)		(3,393)	(80,263)
Fair Value, ending balance		86,365			101,016
Interest income		881	[15]		3,720	[16]
Paid-in-kind interest income		60	[15]	172	3,228	[16]
Dividend income	[16]				8,324
Investment, Identifier [Axis]: AI Aqua Merger Sub, Inc., Capital Goods 1
Derivative [Line Items]
Investments, at fair value		18,051	[2],[17]		16,625	[4],[18],[19]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18],[19]	16,625
Fair Value, ending balance		18,051	[2],[17]		16,625	[4],[18],[19]
Investment, Identifier [Axis]: AI Aqua Merger Sub, Inc., Capital Goods 2
Derivative [Line Items]
Investments, at fair value		2,064	[2],[20]		3,500	[4],[19],[21]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[19],[21]	3,500
Fair Value, ending balance		2,064	[2],[20]		3,500	[4],[19],[21]
Investment, Identifier [Axis]: AIRRO (Mauritius) Holdings II, Energy—Power
Derivative [Line Items]
Investments, at fair value		14,832	[2],[22],[23],[24]		23,050	[4],[25],[26],[27]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[25],[26],[27]	23,050
Fair Value, ending balance		14,832	[2],[22],[23],[24]		23,050	[4],[25],[26],[27]
Investment, Identifier [Axis]: AIRRO (Mauritius) Holdings II, Warrants, Strike, Energy—Power
Derivative [Line Items]
Investments, at fair value	[2],[22],[23],[24],[28]	0
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, ending balance	[2],[22],[23],[24],[28]	0
Investment, Identifier [Axis]: AIRRO (Mauritius) Holdings II, Warrants, Strike: $1.00, Energy—Power
Derivative [Line Items]
Investments, at fair value	[4],[25],[26],[27],[29]				0
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[25],[26],[27],[29]	0
Fair Value, ending balance	[4],[25],[26],[27],[29]				0
Investment, Identifier [Axis]: Abaco Energy Technologies LLC, Common Equity, Energy—Service & Equipment
Derivative [Line Items]
Investments, at fair value		685	[2],[22],[28]		1,375	[4],[25],[29]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[25],[29]	1,375
Fair Value, ending balance		685	[2],[22],[28]		1,375	[4],[25],[29]
Investment, Identifier [Axis]: Abaco Energy Technologies LLC, Preferred Equity, Energy—Service & Equipment
Derivative [Line Items]
Investments, at fair value		5,709	[2],[22],[28],[30]		10,159	[4],[25],[29]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[25],[29]	10,159
Fair Value, ending balance		5,709	[2],[22],[28],[30]		10,159	[4],[25],[29]
Investment, Identifier [Axis]: Acrisure, LLC, Insurance
Derivative [Line Items]
Investments, at fair value		25,269	[2],[17]		20,251	[4],[18]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18]	20,251
Fair Value, ending balance		25,269	[2],[17]		20,251	[4],[18]
Investment, Identifier [Axis]: Aimbridge Acquisition Co. Inc., Consumer Services
Derivative [Line Items]
Investments, at fair value		25,921	[2],[17]		20,380	[4],[18]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18]	20,380
Fair Value, ending balance		25,921	[2],[17]		20,380	[4],[18]
Investment, Identifier [Axis]: AirSwift Holdings, Ltd., Common Equity, Commercial & Professional Services
Derivative [Line Items]
Investments, at fair value		3,806	[2],[22],[24],[28]		3,413	[4],[25],[27],[29]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[25],[27],[29]	3,413
Fair Value, ending balance		3,806	[2],[22],[24],[28]		3,413	[4],[25],[27],[29]
Investment, Identifier [Axis]: Allegiant Travel Co., Transportation
Derivative [Line Items]
Investments, at fair value		$ 10,556	[2],[24]		$ 10,385	[4],[27]
Rate (percent)		7.30%	[24],[31]		7.30%	[27],[32]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[27]	$ 10,385
Fair Value, ending balance		10,556	[2],[24]		$ 10,385	[4],[27]
Investment, Identifier [Axis]: Allied Downhole Technologies, LLC
Derivative [Line Items]
Investments, at fair value					0
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance		0		8,436	8,436
Gross Additions	[12]				138
Gross Reductions	[14]				(8,574)
Net Realized Gain (Loss)					0
Net Change in Unrealized Appreciation (Depreciation)					0
Fair Value, ending balance					0
Interest income	[16]				256
Paid-in-kind interest income	[16]				139
Dividend income	[16]				0
Investment, Identifier [Axis]: Allied Universal Holdco LLC, Consumer Services 1
Derivative [Line Items]
Investments, at fair value		14,479	[2],[17]		9,998	[4],[18]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18]	9,998
Fair Value, ending balance		14,479	[2],[17]		9,998	[4],[18]
Investment, Identifier [Axis]: Allied Universal Holdco LLC, Consumer Services 2
Derivative [Line Items]
Investments, at fair value		9,902	[2],[17]		9,903	[4],[18]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18]	9,903
Fair Value, ending balance		9,902	[2],[17]		9,903	[4],[18]
Investment, Identifier [Axis]: Allied Wireline Services, LLC
Derivative [Line Items]
Investments, at fair value		7,235			22,200
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance		22,200		63,888	63,888
Gross Additions		0	[11]		6,389	[12]
Gross Reductions		0	[13]		0	[14]
Net Realized Gain (Loss)		0			0
Net Change in Unrealized Appreciation (Depreciation)		(14,965)			(48,077)
Fair Value, ending balance		7,235			22,200
Interest income		0	[15]		0	[16]
Paid-in-kind interest income		0	[15]		2,910	[16]
Dividend income	[16]				0
Investment, Identifier [Axis]: Allied Wireline Services, LLC, Common Equity
Derivative [Line Items]
Investments, at fair value		0			0
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance		0		10,463	10,463
Gross Additions		0	[11]		0	[12]
Gross Reductions		0	[13]		0	[14]
Net Realized Gain (Loss)		0			0
Net Change in Unrealized Appreciation (Depreciation)		0			(10,463)
Fair Value, ending balance		0			0
Interest income		0	[15]		0	[16]
Paid-in-kind interest income		0	[15]		0	[16]
Dividend income	[16]				0
Investment, Identifier [Axis]: Allied Wireline Services, LLC, Common Equity, Energy—Service & Equipment
Derivative [Line Items]
Investments, at fair value		0	[2],[22],[28],[33],[34]		0	[4],[25],[29],[35],[36]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[25],[29],[35],[36]	0
Fair Value, ending balance		0	[2],[22],[28],[33],[34]		0	[4],[25],[29],[35],[36]
Investment, Identifier [Axis]: Allied Wireline Services, LLC, Energy—Service & Equipment
Derivative [Line Items]
Investments, at fair value		7,235	[2],[22],[28],[34],[37]		22,200	[4],[25],[29],[36],[38]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[25],[29],[36],[38]	22,200
Fair Value, ending balance		7,235	[2],[22],[28],[34],[37]		22,200	[4],[25],[29],[36],[38]
Investment, Identifier [Axis]: Allied Wireline Services, LLC, Warrants
Derivative [Line Items]
Investments, at fair value		0			0
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance		0		0	0
Gross Additions		0	[11]		0	[12]
Gross Reductions		0	[13]		0	[14]
Net Realized Gain (Loss)		0			0
Net Change in Unrealized Appreciation (Depreciation)		0			0
Fair Value, ending balance		0			0
Interest income		0	[15]		0	[16]
Paid-in-kind interest income		0	[15]		0	[16]
Dividend income	[16]				0
Investment, Identifier [Axis]: Allied Wireline Services, LLC, Warrants, Energy—Service & Equipment
Derivative [Line Items]
Investments, at fair value		0	[2],[22],[28],[33],[34]		0	[4],[25],[29],[35],[36]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[25],[29],[35],[36]	0
Fair Value, ending balance		0	[2],[22],[28],[33],[34]		0	[4],[25],[29],[35],[36]
Investment, Identifier [Axis]: Allspring Government Money Market Fund - Select Class, Money Market Fund
Derivative [Line Items]
Investments, at fair value		$ 59,698			$ 23,098
Rate (percent)		5.20%			5.30%
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance		$ 23,098
Fair Value, ending balance		59,698			$ 23,098
Investment, Identifier [Axis]: American Auto Auction Group, LLC, Capital Goods
Derivative [Line Items]
Investments, at fair value		23,816	[2],[17],[39]		9,858	[4],[18]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18]	9,858
Fair Value, ending balance		23,816	[2],[17],[39]		9,858	[4],[18]
Investment, Identifier [Axis]: Arena Energy, LP, Contingent Value Rights, Energy—Upstream
Derivative [Line Items]
Investments, at fair value		351	[2],[22]		571	[4],[25],[29]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[25],[29]	571
Fair Value, ending balance		351	[2],[22]		571	[4],[25],[29]
Investment, Identifier [Axis]: Aretec Escrow Issuer Inc., Financial Services
Derivative [Line Items]
Investments, at fair value		$ 7,655	[2],[17]		$ 7,447	[4],[18]
Rate (percent)		10%	[17],[31]		10%	[18],[32]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18]	$ 7,447
Fair Value, ending balance		7,655	[2],[17]		$ 7,447	[4],[18]
Investment, Identifier [Axis]: Aretec Group, Inc., Financial Services
Derivative [Line Items]
Investments, at fair value		6,881	[2],[17],[39]		9,358	[4],[18],[19]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18],[19]	9,358
Fair Value, ending balance		6,881	[2],[17],[39]		9,358	[4],[18],[19]
Investment, Identifier [Axis]: Ascent Resources Utica Holdings, LLC, Common Equity, Energy—Upstream
Derivative [Line Items]
Investments, at fair value		36,354	[2],[22],[28],[33]		39,545	[4],[25],[29],[35]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[25],[29],[35]	39,545
Fair Value, ending balance		36,354	[2],[22],[28],[33]		39,545	[4],[25],[29],[35]
Investment, Identifier [Axis]: Auris Luxembourg III S.a r.l, Health Care Equipment & Services
Derivative [Line Items]
Investments, at fair value		20,303	[2],[17],[24]		20,079	[4],[18],[27]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18],[27]	20,079
Fair Value, ending balance		20,303	[2],[17],[24]		20,079	[4],[18],[27]
Investment, Identifier [Axis]: Aveanna Healthcare LLC, Health Care Equipment & Services
Derivative [Line Items]
Investments, at fair value		20,106	[2],[17]		14,852	[4],[18]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18]	14,852
Fair Value, ending balance		20,106	[2],[17]		14,852	[4],[18]
Investment, Identifier [Axis]: BCPE Empire Holdings, Inc., Consumer Services
Derivative [Line Items]
Investments, at fair value		22,450	[2],[17],[39]		24,998	[4],[18]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18]	24,998
Fair Value, ending balance		22,450	[2],[17],[39]		24,998	[4],[18]
Investment, Identifier [Axis]: Bridge Street Warehouse CLO IV Ltd., Financial Services
Derivative [Line Items]
Investments, at fair value	[2],[22],[24],[40],[41]	$ 20,329
Rate (percent)	[22],[24],[31],[40],[41]	1.60%
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, ending balance	[2],[22],[24],[40],[41]	$ 20,329
Investment, Identifier [Axis]: Bridge Street Warehouse CLO IV, Ltd.
Derivative [Line Items]
Investments, at fair value		20,329			0
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance		0
Gross Additions	[5]	20,329
Gross Reductions	[7]	0
Net Realized Gain (Loss)		0
Net Change in Unrealized Appreciation (Depreciation)		0
Fair Value, ending balance		20,329			0
Interest income	[9]	0
Paid-in-kind interest income	[9]	329
Investment, Identifier [Axis]: CCS-CMGC Holdings, Inc., Health Care Equipment & Services
Derivative [Line Items]
Investments, at fair value		22,081	[2],[17]		18,222	[4],[18]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18]	18,222
Fair Value, ending balance		22,081	[2],[17]		18,222	[4],[18]
Investment, Identifier [Axis]: CPM Holdings, Inc., Capital Goods
Derivative [Line Items]
Investments, at fair value		25,002	[2],[17]		20,092	[4],[18]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18]	20,092
Fair Value, ending balance		25,002	[2],[17]		20,092	[4],[18]
Investment, Identifier [Axis]: CT Technologies Intermediate Holdings, Inc., Health Care Equipment & Services
Derivative [Line Items]
Investments, at fair value	[2],[17]	9,968
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, ending balance	[2],[17]	9,968
Investment, Identifier [Axis]: Charlotte Buyer, Inc., Health Care Equipment & Services
Derivative [Line Items]
Investments, at fair value		17,880	[2],[17]		19,952	[4],[18],[19]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18],[19]	19,952
Fair Value, ending balance		17,880	[2],[17]		19,952	[4],[18],[19]
Investment, Identifier [Axis]: CircusTrix Holdings, LLC, Consumer Services 1
Derivative [Line Items]
Investments, at fair value		21,202	[2],[17],[22]		21,098	[4],[18],[25]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18],[25]	21,098
Fair Value, ending balance		21,202	[2],[17],[22]		21,098	[4],[18],[25]
Investment, Identifier [Axis]: CircusTrix Holdings, LLC, Consumer Services 2
Derivative [Line Items]
Investments, at fair value		2,732	[2],[20],[22]		2,712	[4],[21],[25]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[21],[25]	2,712
Fair Value, ending balance		2,732	[2],[20],[22]		2,712	[4],[21],[25]
Investment, Identifier [Axis]: CircusTrix Holdings, LLC, Consumer Services 3
Derivative [Line Items]
Investments, at fair value		1,366	[2],[20],[22]		1,356	[4],[21],[25]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[21],[25]	1,356
Fair Value, ending balance		1,366	[2],[20],[22]		1,356	[4],[21],[25]
Investment, Identifier [Axis]: Cirque Du Soleil Holding USA Newco, Inc., Financial Services
Derivative [Line Items]
Investments, at fair value		8,377	[2],[17]		6,372	[4],[18],[19]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18],[19]	6,372
Fair Value, ending balance		8,377	[2],[17]		6,372	[4],[18],[19]
Investment, Identifier [Axis]: Citizen Energy Operating, LLC, Energy—Upstream
Derivative [Line Items]
Investments, at fair value		33,581	[2],[17],[22]		34,426	[4],[18],[25]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18],[25]	34,426
Fair Value, ending balance		33,581	[2],[17],[22]		34,426	[4],[18],[25]
Investment, Identifier [Axis]: Clear Channel Outdoor Holdings, Inc., Media & Entertainment
Derivative [Line Items]
Investments, at fair value		12,516	[2],[17],[24]		19,829	[4],[18],[27]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18],[27]	19,829
Fair Value, ending balance		12,516	[2],[17],[24]		19,829	[4],[18],[27]
Investment, Identifier [Axis]: Clydesdale Acquisition Holdings Inc., Financial Services
Derivative [Line Items]
Investments, at fair value	[2],[17]	17,449
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, ending balance	[2],[17]	17,449
Investment, Identifier [Axis]: Clydesdale Acquisition Holdings Inc., Financials Services
Derivative [Line Items]
Investments, at fair value	[4],[18]				20,061
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18]	20,061
Fair Value, ending balance	[4],[18]				20,061
Investment, Identifier [Axis]: Cox Oil Offshore, LLC, Volumetric Production Payments, Energy—Upstream
Derivative [Line Items]
Investments, at fair value	[4],[25],[42],[43]				$ 1,234
Rate (percent)	[25],[32],[42],[43]				12.90%
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[25],[42],[43]	1,234
Fair Value, ending balance	[4],[25],[42],[43]				$ 1,234
Investment, Identifier [Axis]: Crown SubSea Communication Holding, Inc., Capital Goods
Derivative [Line Items]
Investments, at fair value	[2],[17]	6,042
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, ending balance	[2],[17]	6,042
Investment, Identifier [Axis]: Crown SubSea Communications Holding, Inc., Capital Goods 1
Derivative [Line Items]
Investments, at fair value	[4],[18],[19]				4,534
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18],[19]	4,534
Fair Value, ending balance	[4],[18],[19]				4,534
Investment, Identifier [Axis]: Crown SubSea Communications Holding, Inc., Capital Goods 2
Derivative [Line Items]
Investments, at fair value	[4],[18],[19]				5,468
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18],[19]	5,468
Fair Value, ending balance	[4],[18],[19]				5,468
Investment, Identifier [Axis]: Delivery Hero Finco LLC, Consumer Services
Derivative [Line Items]
Investments, at fair value	[2],[24],[39]	19,900
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, ending balance	[2],[24],[39]	19,900
Investment, Identifier [Axis]: Digicel International Finance Ltd., Telecommunication Services
Derivative [Line Items]
Investments, at fair value	[2],[17]	19,400
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, ending balance	[2],[17]	19,400
Investment, Identifier [Axis]: Engineered Machinery Holdings, Inc., Capital Goods
Derivative [Line Items]
Investments, at fair value		24,806	[2],[17]		19,840	[4],[18]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18]	19,840
Fair Value, ending balance		24,806	[2],[17]		19,840	[4],[18]
Investment, Identifier [Axis]: FR XIII PAA Holdings HoldCo, LLC, Energy—Midstream
Derivative [Line Items]
Investments, at fair value	[4],[18],[25]				17,156
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18],[25]	17,156
Fair Value, ending balance	[4],[18],[25]				17,156
Investment, Identifier [Axis]: First Brands Group, LLC, Automobiles & Components
Derivative [Line Items]
Investments, at fair value		24,910	[2],[17]		19,781	[4],[18]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18]	19,781
Fair Value, ending balance		24,910	[2],[17]		19,781	[4],[18]
Investment, Identifier [Axis]: Full House Resorts, Inc., Consumer Services
Derivative [Line Items]
Investments, at fair value		$ 24,622	[2],[17]		$ 19,517	[4],[18]
Rate (percent)		8.30%	[17],[31]		8.30%	[18],[32]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18]	$ 19,517
Fair Value, ending balance		24,622	[2],[17]		$ 19,517	[4],[18]
Investment, Identifier [Axis]: GWP Midstream Holdco, LLC, Common Equity
Derivative [Line Items]
Investments, at fair value		2,202			1,661
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance		1,661		5,044	5,044
Gross Additions		0	[5]		0	[6]
Gross Reductions		0	[7]		(3,112)	[8]
Net Realized Gain (Loss)		0			3,112
Net Change in Unrealized Appreciation (Depreciation)		541			(3,383)
Fair Value, ending balance		2,202			1,661
Interest income		0	[9]		0	[10]
Paid-in-kind interest income		0	[9]		0	[10]
Investment, Identifier [Axis]: GWP Midstream Holdco, LLC, Common Equity, Energy—Midstream
Derivative [Line Items]
Investments, at fair value		2,202	[2],[22],[28],[33],[41]		1,661	[4],[25],[29],[35],[44]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[25],[29],[35],[44]	1,661
Fair Value, ending balance		2,202	[2],[22],[28],[33],[41]		1,661	[4],[25],[29],[35],[44]
Investment, Identifier [Axis]: GasLog Ltd., Energy—Midstream
Derivative [Line Items]
Investments, at fair value		13,357	[2],[22],[24]		$ 13,510	[4],[25],[27]
Rate (percent)	[25],[27],[32]				7.80%
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[25],[27]	13,510
Fair Value, ending balance		13,357	[2],[22],[24]		$ 13,510	[4],[25],[27]
Investment, Identifier [Axis]: Global Jet Capital Holdings, LP, Preferred Equity, Commercial & Professional Services 1
Derivative [Line Items]
Investments, at fair value		0	[2],[22],[28],[30]		0	[4],[25],[29]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[25],[29]	0
Fair Value, ending balance		0	[2],[22],[28],[30]		0	[4],[25],[29]
Investment, Identifier [Axis]: Global Jet Capital Holdings, LP, Preferred Equity, Commercial & Professional Services 2
Derivative [Line Items]
Investments, at fair value		$ 10,360	[2],[22],[28],[30],[37]		10,357	[4],[25],[29],[38]
Rate (percent)	[22],[28],[30],[31],[37]	9%
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[25],[29],[38]	$ 10,357
Fair Value, ending balance		10,360	[2],[22],[28],[30],[37]		10,357	[4],[25],[29],[38]
Investment, Identifier [Axis]: Global Tel Link Corp., Technology Hardware & Equipment
Derivative [Line Items]
Investments, at fair value	[2],[17],[39]	13,685
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, ending balance	[2],[17],[39]	13,685
Investment, Identifier [Axis]: Gold Rush Amusements, Inc., Consumer Services
Derivative [Line Items]
Investments, at fair value		30,328	[2],[17],[22]		30,059	[4],[18],[25]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18],[25]	30,059
Fair Value, ending balance		30,328	[2],[17],[22]		30,059	[4],[18],[25]
Investment, Identifier [Axis]: Goodnight Water Solutions, LLC, Energy—Midstream
Derivative [Line Items]
Investments, at fair value		14,238	[2],[17],[22]		14,379	[4],[18],[25]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18],[25]	14,379
Fair Value, ending balance		14,238	[2],[17],[22]		14,379	[4],[18],[25]
Investment, Identifier [Axis]: Guardian US Holdco, LLC, Financial Services
Derivative [Line Items]
Investments, at fair value		24,959	[2],[17]		20,008	[4],[18]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18]	20,008
Fair Value, ending balance		24,959	[2],[17]		20,008	[4],[18]
Investment, Identifier [Axis]: Guitar Center, Inc., Consumer Discretionary Distribution & Retail
Derivative [Line Items]
Investments, at fair value		$ 20,819	[2],[17]		$ 17,473	[4],[18]
Rate (percent)		8.50%	[17],[31]		8.50%	[18],[32]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18]	$ 17,473
Fair Value, ending balance		20,819	[2],[17]		$ 17,473	[4],[18]
Investment, Identifier [Axis]: Harvest Oil & Gas Corp., Common Equity
Derivative [Line Items]
Investments, at fair value		344			271
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance		271		810	810
Gross Additions		0	[5]		0	[6]
Gross Reductions		0	[7]		(641)	[8]
Net Realized Gain (Loss)		0			0
Net Change in Unrealized Appreciation (Depreciation)		73			102
Fair Value, ending balance		344			271
Interest income		0	[9]		0	[10]
Paid-in-kind interest income		0	[9]		0	[10]
Investment, Identifier [Axis]: Harvest Oil & Gas Corp., Common Equity, Energy—Upstream
Derivative [Line Items]
Investments, at fair value		344	[2],[22],[28],[41]		271	[4],[29],[44]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[29],[44]	271
Fair Value, ending balance		344	[2],[22],[28],[41]		271	[4],[29],[44]
Investment, Identifier [Axis]: Knowlton Development Corporation Inc., Household & Personal Products
Derivative [Line Items]
Investments, at fair value		26,081	[2],[17]		20,858	[4],[18]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18]	20,858
Fair Value, ending balance		26,081	[2],[17]		20,858	[4],[18]
Investment, Identifier [Axis]: LABL, Inc., Commercial & Professional Services
Derivative [Line Items]
Investments, at fair value	[2],[17]	24,343
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, ending balance	[2],[17]	24,343
Investment, Identifier [Axis]: LABL, Inc., Commerical & Professional Services
Derivative [Line Items]
Investments, at fair value	[4],[18]				19,106
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18]	19,106
Fair Value, ending balance	[4],[18]				19,106
Investment, Identifier [Axis]: LaserShip, Inc., Transportation
Derivative [Line Items]
Investments, at fair value	[2],[17]	6,523
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, ending balance	[2],[17]	6,523
Investment, Identifier [Axis]: Learning Care Group No. 2 Inc., Consumer Services
Derivative [Line Items]
Investments, at fair value		21,959	[2],[17]		20,100	[4],[18]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18]	20,100
Fair Value, ending balance		21,959	[2],[17]		20,100	[4],[18]
Investment, Identifier [Axis]: Limetree Bay Energy, LLC, Class A Units
Derivative [Line Items]
Investments, at fair value					0
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance		0		1,885	1,885
Gross Additions	[6]				246
Gross Reductions	[8]				0
Net Realized Gain (Loss)					(21,704)
Net Change in Unrealized Appreciation (Depreciation)					19,573
Fair Value, ending balance					0
Interest income	[10]				0
Paid-in-kind interest income	[10]				0
Investment, Identifier [Axis]: MBS Services Holdings, LLC, A-3 Units, Commercial & Professional Services
Derivative [Line Items]
Investments, at fair value	[2],[22],[28],[33]	0
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, ending balance	[2],[22],[28],[33]	0
Investment, Identifier [Axis]: MBS Services Holdings, LLC, Commercial & Professional Services
Derivative [Line Items]
Investments, at fair value	[2],[22]	$ 28,049
Rate (percent)	[22],[31]	15%
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, ending balance	[2],[22]	$ 28,049
Investment, Identifier [Axis]: Maverick Natural Resources, LLC, Common Equity, Energy—Upstream
Derivative [Line Items]
Investments, at fair value		78,546	[2],[22],[33]		164,040	[4],[25],[29],[35]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[25],[29],[35]	164,040
Fair Value, ending balance		78,546	[2],[22],[33]		164,040	[4],[25],[29],[35]
Investment, Identifier [Axis]: Mavis Tire Express Services TopCo, L.P., Consumer Discretionary Distribution & Retail
Derivative [Line Items]
Investments, at fair value		17,399	[2],[17]		19,955	[4],[18]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18]	19,955
Fair Value, ending balance		17,399	[2],[17]		19,955	[4],[18]
Investment, Identifier [Axis]: NGL Energy Partners, LP, Preferred Equity, Energy—Midstream
Derivative [Line Items]
Investments, at fair value		$ 222,338	[2],[17],[22],[24],[30],[37]		$ 141,141	[4],[18],[25],[27],[29],[38]
Rate (percent)		14.20%	[17],[22],[24],[30],[31],[37]		14.20%	[18],[25],[27],[29],[32],[38]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18],[25],[27],[29],[38]	$ 141,141
Fair Value, ending balance		222,338	[2],[17],[22],[24],[30],[37]		$ 141,141	[4],[18],[25],[27],[29],[38]
Investment, Identifier [Axis]: NGL Energy Partners, LP, Warrants (Par), Strike, Energy—Midstream
Derivative [Line Items]
Investments, at fair value	[2],[22],[24],[28]	2,472
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, ending balance	[2],[22],[24],[28]	2,472
Investment, Identifier [Axis]: NGL Energy Partners, LP, Warrants (Par), Strike, Energy—Midstream 2
Derivative [Line Items]
Investments, at fair value	[2],[22],[24],[28]	589
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, ending balance	[2],[22],[24],[28]	589
Investment, Identifier [Axis]: NGL Energy Partners, LP, Warrants (Par), Strike: $13.56, Energy—Midstream
Derivative [Line Items]
Investments, at fair value	[4],[25],[27],[29]				621
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[25],[27],[29]	621
Fair Value, ending balance	[4],[25],[27],[29]				621
Investment, Identifier [Axis]: NGL Energy Partners, LP, Warrants (Par), Strike: $14.54, Energy—Midstream
Derivative [Line Items]
Investments, at fair value	[4],[25],[27],[29]				2,682
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[25],[27],[29]	2,682
Fair Value, ending balance	[4],[25],[27],[29]				2,682
Investment, Identifier [Axis]: NGL Energy Partners, LP, Warrants (Premium), Strike, Energy—Midstream 1
Derivative [Line Items]
Investments, at fair value	[2],[22],[24],[28]	2,808
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, ending balance	[2],[22],[24],[28]	2,808
Investment, Identifier [Axis]: NGL Energy Partners, LP, Warrants (Premium), Strike, Energy—Midstream 2
Derivative [Line Items]
Investments, at fair value	[2],[22],[24],[28]	660
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, ending balance	[2],[22],[24],[28]	660
Investment, Identifier [Axis]: NGL Energy Partners, LP, Warrants (Premium), Strike: $16.27, Energy—Midstream
Derivative [Line Items]
Investments, at fair value	[4],[25],[27],[29]				735
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[25],[27],[29]	735
Fair Value, ending balance	[4],[25],[27],[29]				735
Investment, Identifier [Axis]: NGL Energy Partners, LP, Warrants (Premium), Strike: $17.45, Energy—Midstream
Derivative [Line Items]
Investments, at fair value	[4],[25],[27],[29]				3,083
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[25],[27],[29]	3,083
Fair Value, ending balance	[4],[25],[27],[29]				3,083
Investment, Identifier [Axis]: Navios Logistics Finance, Inc., Transportation
Derivative [Line Items]
Investments, at fair value		$ 25,013	[2],[17],[24]		$ 19,772	[4],[18],[27]
Rate (percent)		10.80%	[17],[24],[31]		10.80%	[18],[27],[32]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18],[27]	$ 19,772
Fair Value, ending balance		25,013	[2],[17],[24]		$ 19,772	[4],[18],[27]
Investment, Identifier [Axis]: Nephron Pharmaceuticals Corp., Pharmaceuticals, Biotechnology & Life Sciences
Derivative [Line Items]
Investments, at fair value		19,352	[2],[22]		19,300	[4],[25]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[25]	19,300
Fair Value, ending balance		19,352	[2],[22]		19,300	[4],[25]
Investment, Identifier [Axis]: Osaic Holdings, Inc., Financial Services
Derivative [Line Items]
Investments, at fair value	[2],[17],[39]	5,013
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, ending balance	[2],[17],[39]	5,013
Investment, Identifier [Axis]: Permian Production Holdings, LLC
Derivative [Line Items]
Investments, at fair value		4,050			4,816
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance		4,816		4,767	4,767
Gross Additions		58	[5]		231	[6]
Gross Reductions		(828)	[7]		0	[8]
Net Realized Gain (Loss)		71			0
Net Change in Unrealized Appreciation (Depreciation)		(67)			(182)
Fair Value, ending balance		4,050			4,816
Interest income		160	[9]		675	[10]
Paid-in-kind interest income		23	[9]		97	[10]
Investment, Identifier [Axis]: Permian Production Holdings, LLC, Common Equity
Derivative [Line Items]
Investments, at fair value		1,043			748
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance		748		11,420	11,420
Gross Additions		0	[5]		0	[6]
Gross Reductions		0	[7]		0	[8]
Net Realized Gain (Loss)		0			0
Net Change in Unrealized Appreciation (Depreciation)		295			(10,672)
Fair Value, ending balance		1,043			748
Interest income		0	[9]		0	[10]
Paid-in-kind interest income		0	[9]		0	[10]
Investment, Identifier [Axis]: Permian Production Holdings, LLC, Common Equity, Energy—Upstream
Derivative [Line Items]
Investments, at fair value		1,043	[2],[22],[28],[33],[41]		748	[4],[25],[29],[35],[44]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[25],[29],[35],[44]	748
Fair Value, ending balance		1,043	[2],[22],[28],[33],[41]		748	[4],[25],[29],[35],[44]
Investment, Identifier [Axis]: Permian Production Holdings, LLC, Energy—Upstream
Derivative [Line Items]
Investments, at fair value		$ 4,050	[2],[22],[41]		$ 4,816	[4],[25],[44]
Rate (percent)		7%	[22],[31],[41]		7%	[25],[32],[44]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[25],[44]	$ 4,816
Fair Value, ending balance		4,050	[2],[22],[41]		$ 4,816	[4],[25],[44]
Investment, Identifier [Axis]: Phoenix Guarantor Inc., Financial Services
Derivative [Line Items]
Investments, at fair value	[4],[18],[19]				19,951
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18],[19]	19,951
Fair Value, ending balance	[4],[18],[19]				19,951
Investment, Identifier [Axis]: Plainfield Renewable Energy Holdings LLC, Energy—Power 2
Derivative [Line Items]
Investments, at fair value	[2],[22],[28],[37]	0
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, ending balance	[2],[22],[28],[37]	0
Investment, Identifier [Axis]: Plainfield Renewable Energy Holdings LLC, Energy—Power 1
Derivative [Line Items]
Investments, at fair value		$ 4,592	[2],[22],[28],[37]		$ 7,473	[4],[25],[29],[38]
Rate (percent)		6%	[22],[28],[31],[37]		6%	[25],[29],[32],[38]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[25],[29],[38]	$ 7,473
Fair Value, ending balance		4,592	[2],[22],[28],[37]		$ 7,473	[4],[25],[29],[38]
Investment, Identifier [Axis]: Plainfield Renewable Energy Holdings LLC, Energy—Power 2
Derivative [Line Items]
Investments, at fair value	[4],[25],[29],[38]				0
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[25],[29],[38]	0
Fair Value, ending balance	[4],[25],[29],[38]				0
Investment, Identifier [Axis]: Plainfield Renewable Energy Holdings LLC, Letter of Credit, Energy—Power
Derivative [Line Items]
Investments, at fair value		$ 0	[2],[20],[22]		$ 0	[4],[21],[25]
Rate (percent)		10%	[20],[22],[31]		10%	[21],[25],[32]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[21],[25]	$ 0
Fair Value, ending balance		0	[2],[20],[22]		$ 0	[4],[21],[25]
Investment, Identifier [Axis]: Pretium PKG Holdings, Inc., Materials
Derivative [Line Items]
Investments, at fair value		32,883	[2],[17]		29,591	[4],[18]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18]	29,591
Fair Value, ending balance		32,883	[2],[17]		29,591	[4],[18]
Investment, Identifier [Axis]: Pro Mach Group, Inc., Capital Goods
Derivative [Line Items]
Investments, at fair value		17,506	[2],[17]		20,007	[4],[18]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18]	20,007
Fair Value, ending balance		17,506	[2],[17]		20,007	[4],[18]
Investment, Identifier [Axis]: Proampac PG Borrower LLC, Materials
Derivative [Line Items]
Investments, at fair value		23,023	[2],[17]		20,062	[4],[18]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18]	20,062
Fair Value, ending balance		23,023	[2],[17]		20,062	[4],[18]
Investment, Identifier [Axis]: RealTruck Group, Inc., Automobiles & Components
Derivative [Line Items]
Investments, at fair value	[2],[17]	24,729
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, ending balance	[2],[17]	24,729
Investment, Identifier [Axis]: Realtruck Group, Inc., Automobiles & Components
Derivative [Line Items]
Investments, at fair value	[4],[18],[19]				19,740
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18],[19]	19,740
Fair Value, ending balance	[4],[18],[19]				19,740
Investment, Identifier [Axis]: Ridgeback Resources Inc., Common Equity
Derivative [Line Items]
Investments, at fair value					0
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance		0		41,851	41,851
Gross Additions	[6]				0
Gross Reductions	[8]				(35,240)
Net Realized Gain (Loss)					(11,359)
Net Change in Unrealized Appreciation (Depreciation)					4,748
Fair Value, ending balance					0
Interest income	[10]				0
Paid-in-kind interest income	[10]				0
Investment, Identifier [Axis]: Ryan, LLC, Commercial & Professional Services 1
Derivative [Line Items]
Investments, at fair value	[2],[17]	9,905
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, ending balance	[2],[17]	9,905
Investment, Identifier [Axis]: Ryan, LLC, Commercial & Professional Services 2
Derivative [Line Items]
Investments, at fair value	[2],[20]	1,043
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, ending balance	[2],[20]	1,043
Investment, Identifier [Axis]: Ryan, LLC, Commerical & Professional Services 1
Derivative [Line Items]
Investments, at fair value	[4],[18],[19]				9,890
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18],[19]	9,890
Fair Value, ending balance	[4],[18],[19]				9,890
Investment, Identifier [Axis]: Ryan, LLC, Commerical & Professional Services 2
Derivative [Line Items]
Investments, at fair value	[4],[19],[21]				1,041
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[19],[21]	1,041
Fair Value, ending balance	[4],[19],[21]				1,041
Investment, Identifier [Axis]: SRS Distribution Inc., Capital Goods
Derivative [Line Items]
Investments, at fair value		25,060	[2],[17]		19,982	[4],[18],[19]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18],[19]	19,982
Fair Value, ending balance		25,060	[2],[17]		19,982	[4],[18],[19]
Investment, Identifier [Axis]: ST EIP Holdings Inc., Energy—Midstream
Derivative [Line Items]
Investments, at fair value		$ 9,771	[2],[17],[22]		$ 9,874	[4],[18],[25]
Rate (percent)		6.30%	[17],[22],[31]		6.30%	[18],[25],[32]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18],[25]	$ 9,874
Fair Value, ending balance		9,771	[2],[17],[22]		$ 9,874	[4],[18],[25]
Investment, Identifier [Axis]: Sustainable Infrastructure Investments, LLC
Derivative [Line Items]
Investments, at fair value					39,427
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance		39,427		51,098	51,098
Gross Additions	[12]				0
Gross Reductions	[14]				(11,364)
Net Realized Gain (Loss)					0
Net Change in Unrealized Appreciation (Depreciation)					(307)
Fair Value, ending balance					39,427
Interest income	[16]				0
Paid-in-kind interest income	[16]				0
Dividend income	[16]				8,324
Investment, Identifier [Axis]: Sustainable Infrastructure Investments, LLC 2
Derivative [Line Items]
Investments, at fair value		40,830			39,427
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance		39,427
Gross Additions	[11]	0
Gross Reductions	[13]	0
Net Realized Gain (Loss)		0
Net Change in Unrealized Appreciation (Depreciation)		1,403
Fair Value, ending balance		40,830			39,427
Interest income	[15]	0
Paid-in-kind interest income	[15]	0
Investment, Identifier [Axis]: Sustainable Infrastructure Investments, LLC, Energy—Power
Derivative [Line Items]
Investments, at fair value		40,830	[2],[22],[24],[34]		39,427	[4],[25],[27],[36]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[25],[27],[36]	39,427
Fair Value, ending balance		40,830	[2],[22],[24],[34]		39,427	[4],[25],[27],[36]
Investment, Identifier [Axis]: TKC Holdings, Inc., Consumer Staples Distribution & Retail
Derivative [Line Items]
Investments, at fair value		24,337	[2],[17]		18,830	[4],[18]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18]	18,830
Fair Value, ending balance		24,337	[2],[17]		18,830	[4],[18]
Investment, Identifier [Axis]: Telpico, LLC, Common Equity
Derivative [Line Items]
Investments, at fair value		0			0
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance		0		0	0
Gross Additions		0	[5]		0	[6]
Gross Reductions		0	[7]		0	[8]
Net Realized Gain (Loss)		0			0
Net Change in Unrealized Appreciation (Depreciation)		0			0
Fair Value, ending balance		0			0
Interest income		0	[9]		0	[10]
Paid-in-kind interest income		0	[9]		0	[10]
Investment, Identifier [Axis]: Telpico, LLC, Common Equity, Energy—Upstream
Derivative [Line Items]
Investments, at fair value		0	[2],[22],[28],[33],[41]		0	[4],[25],[29],[35],[44]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[25],[29],[35],[44]	0
Fair Value, ending balance		0	[2],[22],[28],[33],[41]		0	[4],[25],[29],[35],[44]
Investment, Identifier [Axis]: Tenrgys, LLC, Common Equity, Energy—Upstream
Derivative [Line Items]
Investments, at fair value		1,245	[2],[22],[28],[33]		4,418	[4],[25],[29],[35]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[25],[29],[35]	4,418
Fair Value, ending balance		1,245	[2],[22],[28],[33]		4,418	[4],[25],[29],[35]
Investment, Identifier [Axis]: Tenrgys, LLC, Energy—Upstream
Derivative [Line Items]
Investments, at fair value		20,306	[2],[17],[22]		19,998	[4],[18],[25]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18],[25]	19,998
Fair Value, ending balance		20,306	[2],[17],[22]		19,998	[4],[18],[25]
Investment, Identifier [Axis]: TruGreen, LP, Commercial & Professional Services
Derivative [Line Items]
Investments, at fair value		24,230	[2],[17]		19,268	[4],[18]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18]	19,268
Fair Value, ending balance		24,230	[2],[17]		19,268	[4],[18]
Investment, Identifier [Axis]: U.S. Treasury Bills, U.S. Treasury 1
Derivative [Line Items]
Investments, at fair value	[2],[45],[46]	99,884
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, ending balance	[2],[45],[46]	99,884
Investment, Identifier [Axis]: U.S. Treasury Bills, U.S. Treasury 2
Derivative [Line Items]
Investments, at fair value	[2],[45],[46]	26,941
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, ending balance	[2],[45],[46]	26,941
Investment, Identifier [Axis]: U.S. Treasury Bills, U.S. Treasury Bills
Derivative [Line Items]
Investments, at fair value	[4],[47]				21,000
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[47]	21,000
Fair Value, ending balance	[4],[47]				21,000
Investment, Identifier [Axis]: USA Compression Partners, LP, Preferred Equity, Energy—Midstream
Derivative [Line Items]
Investments, at fair value		$ 86,324	[2],[17],[22],[24],[30]		$ 98,333	[4],[18],[25],[27]
Rate (percent)		9.80%	[17],[22],[24],[30],[31]		9.80%	[18],[25],[27],[32]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18],[25],[27]	$ 98,333
Fair Value, ending balance		86,324	[2],[17],[22],[24],[30]		$ 98,333	[4],[18],[25],[27]
Investment, Identifier [Axis]: WMK, LLC, Consumer Discretionary Distribution & Retail 1
Derivative [Line Items]
Investments, at fair value	[2],[17],[22]	28,956
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, ending balance	[2],[17],[22]	28,956
Investment, Identifier [Axis]: WMK, LLC, Consumer Discretionary Distribution & Retail 2
Derivative [Line Items]
Investments, at fair value	[2],[20],[22]	5,015
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, ending balance	[2],[20],[22]	5,015
Investment, Identifier [Axis]: Warren Resources, Inc.
Derivative [Line Items]
Investments, at fair value		23,883			23,823
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance		23,823		23,584	23,584
Gross Additions		60	[11]		239	[12]
Gross Reductions		0	[13]		0	[14]
Net Realized Gain (Loss)		0			0
Net Change in Unrealized Appreciation (Depreciation)		0			0
Fair Value, ending balance		23,883			23,823
Interest income		881	[15]		3,464	[16]
Paid-in-kind interest income		60	[15]		179	[16]
Dividend income	[16]				0
Investment, Identifier [Axis]: Warren Resources, Inc., Common Equity
Derivative [Line Items]
Investments, at fair value		14,417			15,566
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance		15,566		$ 36,982	36,982
Gross Additions		127	[11]		0	[12]
Gross Reductions		0	[13]		0	[14]
Net Realized Gain (Loss)		0			0
Net Change in Unrealized Appreciation (Depreciation)		(1,276)			(21,416)
Fair Value, ending balance		14,417			15,566
Interest income		0	[15]		0	[16]
Paid-in-kind interest income		0	[15]		0	[16]
Dividend income	[16]				0
Investment, Identifier [Axis]: Warren Resources, Inc., Common Equity, Energy—Upstream
Derivative [Line Items]
Investments, at fair value		14,417	[2],[22],[28],[34]		15,566	[4],[25],[29],[36]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[25],[29],[36]	15,566
Fair Value, ending balance		14,417	[2],[22],[28],[34]		15,566	[4],[25],[29],[36]
Investment, Identifier [Axis]: Warren Resources, Inc., Energy—Upstream
Derivative [Line Items]
Investments, at fair value		23,883	[2],[17],[22],[34]		23,823	[4],[18],[25],[36]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18],[25],[36]	23,823
Fair Value, ending balance		23,883	[2],[17],[22],[34]		23,823	[4],[18],[25],[36]
Investment, Identifier [Axis]: Wattbridge Inc., Energy—Power
Derivative [Line Items]
Investments, at fair value		41,866	[2],[17],[22]		41,882	[4],[18],[25]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, beginning balance	[4],[18],[25]	41,882
Fair Value, ending balance		41,866	[2],[17],[22]		$ 41,882	[4],[18],[25]
Investment, Identifier [Axis]: Weber-Stephen Products LLC, Consumer Durables & Apparel
Derivative [Line Items]
Investments, at fair value	[2],[17],[39]	24,404
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Fair Value, ending balance	[2],[17],[39]	$ 24,404
One-Month Secured Overnight Financing Rate
Derivative [Line Items]
Investment, variable rate					5.35%
Three-Month Secured Overnight Financing Rate
Derivative [Line Items]
Investment, variable rate					5.33%
Overnight Bank Funding Rate
Derivative [Line Items]
Investment, variable rate					5.32%

[1]Security may be an obligation of one or more entities affiliated with the named company.[2]See Note 8 for additional information regarding the fair value of the Company’s financial instruments.[3]Security may be an obligation of one or more entities affiliated with the named company.[4]See Note 8 for additional information regarding the fair value of the Company’s financial instruments.[5]Gross additions may include increases in the cost basis of investments resulting from new portfolio investments, PIK interest, the amortization of unearned income, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company into this category from a different category.[6]Gross additions may include increases in the cost basis of investments resulting from new portfolio investments, PIK interest, the amortization of unearned income, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company into this category from a different category.[7]Gross reductions may include decreases in the cost basis of investments resulting from principal collections related to investment repayments or sales, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company out of this category into a different category.[8]Gross reductions may include decreases in the cost basis of investments resulting from principal collections related to investment repayments or sales, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company out of this category into a different category.[9]Interest and PIK income presented for the three months ended March 31, 2024.[10]Interest and PIK income presented for the year ended December 31, 2023[11]Gross additions may include increases in the cost basis of investments resulting from new portfolio investments, PIK interest, the amortization of unearned income, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company into this category from a different category.[12]Gross additions may include increases in the cost basis of investments resulting from new portfolio investments, PIK interest, the amortization of unearned income, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company into this category from a different category.[13] Gross reductions may include decreases in the cost basis of investments resulting from principal collections related to investment repayments or sales, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company out of this category into a different category.[14]Gross reductions may include decreases in the cost basis of investments resulting from principal collections related to investment repayments or sales, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company out of this category into a different category.[15]Interest and PIK income presented for the three months ended March 31, 2024.[16]Interest, PIK and dividend income presented for the year ended December 31, 2023.[17]Security or portion thereof held within FSSL Finance BB AssetCo LLC, a wholly-owned subsidiary of the Company, and is pledged as collateral supporting the obligations outstanding under the repurchase facility with Barclays Bank PLC (see Note 9).[18]Security or portion thereof held within FSSL Finance BB AssetCo LLC, a wholly-owned subsidiary of the Company, and is pledged as collateral supporting the obligations outstanding under the repurchase facility with Barclays Bank PLC (see Note 9).[19]Security or portion thereof unsettled as of December 31, 2023.[20]Security is an unfunded commitment. The stated rate reflects the spread disclosed at the time of commitment and may not indicate the actual rate received upon funding.[21]Security is an unfunded commitment. The stated rate reflects the spread disclosed at the time of commitment and may not indicate the actual rate received upon funding.[22]Security is classified as Level 3 in the Company’s fair value hierarchy (see Note 8).[23]Security or portion thereof held within FS Power Investments II, LLC, a wholly-owned subsidiary of the Company.[24]The investment is not a qualifying asset under the Investment Company Act of 1940, as amended, or the 1940 Act. A business development company may not acquire any asset other than a qualifying asset, unless, at the time the acquisition is made, qualifying assets represent at least 70% of the business development company’s total assets. As of March 31, 2024, 75.7% of the Company’s total assets represented qualifying assets.[25]Security is classified as Level 3 in the Company’s fair value hierarchy (see Note 8).[26]Security or portion thereof held within FS Power Investments II, LLC, a wholly-owned subsidiary of the Company.[27]The investment is not a qualifying asset under the Investment Company Act of 1940, as amended, or the 1940 Act. A business development company may not acquire any asset other than a qualifying asset, unless, at the time the acquisition is made, qualifying assets represent at least 70% of the business development company’s total assets. As of December 31, 2023, 80.8% of the Company’s total assets represented qualifying assets.[28]Security is non-income producing.[29]Security is non-income producing.[30]Includes $59,698 held in Allspring Government Money Market Fund with a 7-day yield of 5.2% as of March 31, 2024.[31]Certain variable rate securities in the Company’s portfolio bear interest at a rate determined by a publicly disclosed base rate plus a basis point spread. As of March 31, 2024, the one-month and three-month Secured Overnight Financing Rate, or SOFR, or S, was 5.33% and 5.30%, respectively, and the Overnight Bank Funding Rate, or OBFR, was 5.33%. SOFR based contracts may include a credit spread adjustment that is charged in addition to the base rate and basis point spread. PIK means paid-in-kind. PIK income accruals may be adjusted based on the fair value of the underlying investment. Variable rate securities with no floor rate use the respective benchmark rate in all cases.[32]Certain variable rate securities in the Company’s portfolio bear interest at a rate determined by a publicly disclosed base rate plus a basis point spread. As of December 31, 2023, the one-month and three-month Secured Overnight Financing Rate, or SOFR, or S, was 5.35% and 5.33%, respectively, and the Overnight Bank Funding Rate, or OBFR, was 5.32%. SOFR based contracts may include a credit spread adjustment that is charged in addition to the base rate and basis point spread. PIK means paid-in-kind. PIK income accruals may be adjusted based on the fair value of the underlying investment. Variable rate securities with no floor rate use the respective benchmark rate in all cases.[33]Security held within FSEP Investments, Inc., a wholly-owned subsidiary of the Company.[34]Under the 1940 Act, the Company generally is deemed to “control” a portfolio company if it owns more than 25% of the portfolio company’s voting securities or it has the power to exercise control over the management or policies of such portfolio company. As of March 31, 2024, the Company held investments in portfolio companies of which it is deemed to be an “affiliated person” of and deemed to “control.” The following table presents certain information with respect to investments in portfolio companies of which the Company was deemed to be an affiliated person and deemed to control as of March 31, 2024: Portfolio Company Fair Value at December 31, 2023 Gross Additions (1) Gross Reductions (2) Net Realized Gain (Loss) Net Change in Unrealized Appreciation (Depreciation) Fair Value at March 31, 2024 Interest Income (3) PIK Income (3) Senior Secured Loans—First Lien Allied Wireline Services, LLC $ 22,200 $ — $ — $ — $ (14,965) $ 7,235 $ — $ — Warren Resources, Inc. 23,823 60 — — — 23,883 881 60 Sustainable Infrastructure Investments, LLC Sustainable Infrastructure Investments, LLC 39,427 — — — 1,403 40,830 — — Equity/Other Allied Wireline Services, LLC, Common Equity — — — — — — — — Allied Wireline Services, LLC, Warrants — — — — — — — — Warren Resources, Inc., Common Equity 15,566 127 — — (1,276) 14,417 — — $ 101,016 $ 187 $ — $ — $ (14,838) $ 86,365 $ 881 $ 60 _____________ (1) Gross additions may include increases in the cost basis of investments resulting from new portfolio investments, PIK interest, the amortization of unearned income, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company into this category from a different category. (2) Gross reductions may include decreases in the cost basis of investments resulting from principal collections related to investment repayments or sales, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company out of this category into a different category. (3) Interest and PIK income presented for the three months ended March 31, 2024. Portfolio Company Fair Value at December 31, 2022 Gross Additions (1) Gross Reductions (2) Net Realized Gain (Loss) Net Change in Unrealized Appreciation (Depreciation) Fair Value at December 31, 2023 Interest Income (3) PIK Income (3) Dividend Income (3) Senior Secured Loans—First Lien Allied Downhole Technologies, LLC $ 8,436 $ 138 $ (8,574) $ — $ — $ — $ 256 $ 139 $ — Allied Wireline Services, LLC 63,888 6,389 — — (48,077) 22,200 — 2,910 — Warren Resources, Inc. 23,584 239 — — — 23,823 3,464 179 — Sustainable Infrastructure Investments, LLC Sustainable Infrastructure Investments, LLC 51,098 — (11,364) — (307) 39,427 — — 8,324 Equity/Other Allied Wireline Services, LLC, Common Equity 10,463 — — — (10,463) — — — — Allied Wireline Services, LLC, Warrants — — — — — — — — — Warren Resources, Inc., Common Equity 36,982 — — — (21,416) 15,566 — — — $ 194,451 $ 6,766 $ (19,938) $ — $ (80,263) $ 101,016 $ 3,720 $ 3,228 $ 8,324 _____________ (1) Gross additions may include increases in the cost basis of investments resulting from new portfolio investments, PIK interest, the amortization of unearned income, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company into this category from a different category. (2) Gross reductions may include decreases in the cost basis of investments resulting from principal collections related to investment repayments or sales, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company out of this category into a different category. (3) Interest, PIK and dividend income presented for the year ended December 31, 2023. Portfolio Company Fair Value at December 31, 2023 Gross Additions (1) Gross Reductions (2) Net Realized Gain (Loss) Net Change in Unrealized Appreciation (Depreciation) Fair Value at March 31, 2024 Interest Income (3) PIK Income (3) Senior Secured Loans—First Lien Permian Production Holdings, LLC $ 4,816 $ 58 $ (828) $ 71 $ (67) $ 4,050 $ 160 $ 23 Asset Based Finance Bridge Street Warehouse CLO IV Ltd. — 20,329 — — — 20,329 — 329 Equity/Other GWP Midstream Holdco, LLC, Common Equity 1,661 — — — 541 2,202 — — Harvest Oil & Gas Corp., Common Equity 271 — — — 73 344 — — Permian Production Holdings, LLC, Common Equity 748 — — — 295 1,043 — — Telpico, LLC, Common Equity — — — — — — — — $ 7,496 $ 20,387 $ (828) $ 71 $ 842 $ 27,968 $ 160 $ 352 _____________ (1) Gross additions may include increases in the cost basis of investments resulting from new portfolio investments, PIK interest, the amortization of unearned income, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company into this category from a different category. (2) Gross reductions may include decreases in the cost basis of investments resulting from principal collections related to investment repayments or sales, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company out of this category into a different category. (3) Interest and PIK income presented for the three months ended March 31, 2024. Portfolio Company Fair Value at December 31, 2022 Gross Additions (1) Gross Reductions (2) Net Realized Gain (Loss) Net Change in Unrealized Appreciation (Depreciation) Fair Value at December 31, 2023 Interest Income (3) PIK Income (3) Senior Secured Loans—First Lien Permian Production Holdings, LLC $ 4,767 $ 231 $ — $ — $ (182) $ 4,816 $ 675 $ 97 Equity/Other GWP Midstream Holdco, LLC, Common Equity 5,044 — (3,112) 3,112 (3,383) 1,661 — — Harvest Oil & Gas Corp., Common Equity 810 — (641) — 102 271 — — Limetree Bay Energy, LLC, Class A Units 1,885 246 — (21,704) 19,573 — — — Permian Production Holdings, LLC, Common Equity 11,420 — — — (10,672) 748 — — Ridgeback Resources Inc., Common Equity 41,851 — (35,240) (11,359) 4,748 — — — Telpico, LLC, Common Equity — — — — — — — — $ 65,777 $ 477 $ (38,993) $ (29,951) $ 10,186 $ 7,496 $ 675 $ 97 _____________ (1) Gross additions may include increases in the cost basis of investments resulting from new portfolio investments, PIK interest, the amortization of unearned income, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company into this category from a different category. (2) Gross reductions may include decreases in the cost basis of investments resulting from principal collections related to investment repayments or sales, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company out of this category into a different category. (3) Interest and PIK income presented for the year ended December 31, 2023.

Principal Business and Organiza

Principal Business and Organization	3 Months Ended
Principal Business and Organization	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Principal Business and Organization	Principal Business and Organization FS Specialty Lending Fund, or the Company, was formed as a Delaware statutory trust under the Delaware Statutory Trust Act on September 16, 2010 and formally commenced investment operations on July 18, 2011. Prior to September 29, 2023, the Company’s name was FS Energy and Power Fund. The Company is an externally managed, non-diversified, closed-end management investment company that has elected to be regulated as a business development company, or BDC, under the Investment Company Act of 1940, as amended, or the 1940 Act. In addition, the Company has elected to be treated for U.S. federal income tax purposes, and intends to qualify annually, as a regulated investment company, or RIC, as defined under Subchapter M of the Internal Revenue Code of 1986, as amended, or the Code. The Company has various wholly-owned financing subsidiaries, including special-purpose financing subsidiaries and subsidiaries through which it holds or expects to hold interests in certain portfolio companies. The unaudited consolidated financial statements include both the Company’s accounts and the accounts of its wholly-owned subsidiaries as of March 31, 2024. All significant intercompany transactions have been eliminated in consolidation. Certain of the Company’s consolidated subsidiaries are subject to U.S. federal and state income taxes. On May 15, 2023, the Company announced that its board of trustees approved the Company’s transition from an investment policy of investing primarily in energy companies to a diversified credit investment policy of investing across private and public credit in a broader set of industries, sectors and sub-sectors. The Company notified its shareholders of the new policy, which became effective on September 29, 2023. The Company’s current investment objectives are to generate current income and, to a lesser extent, long-term capital appreciation by investing primarily in private and public credit in a broad set of industries, sectors and sub-sectors. The Company’s current investment policy is to invest primarily in a portfolio of secured and unsecured floating and fixed rate loans, bonds and other types of credit instruments, which, under normal circumstances, will represent at least 80% of the Company’s total assets. Prior to September 29, 2023, the Company’s investment objectives were to generate current income and long-term capital appreciation by investing primarily in privately-held U.S. companies in the energy and power industry. Prior to September 29, 2023, the Company’s investment policy was to invest, under normal circumstances, at least 80% of its total assets in securities of energy and power related, or Energy, companies. The Company considers Energy companies to be those companies that engage in the exploration, development, production, gathering, transportation, processing, storage, refining, distribution, mining, generation or marketing of natural gas, natural gas liquids, crude oil, refined products, coal or power, including those companies that provide equipment or services to companies engaged in any of the foregoing. The Company commenced transitioning the Company’s portfolio holdings away from Energy investments in May 2023, while remaining in compliance with the Company’s then-current investment policy. The Company’s allocation to Energy investments is expected to decline over time through the natural course of maturities, repayments and sales activity and by growing the total size of the portfolio through leverage facilities. The pace of the portfolio rotation is dependent upon a number of factors, including the turnover of concentrated illiquid Energy investments, performance of underlying portfolio companies, high yield and energy market conditions, the Company’s access to borrowings and the amount and pace of the payment of enhanced distributions to shareholders, among others. The Company is managed by FS/EIG Advisor, LLC, or FS/EIG Advisor, pursuant to an investment advisory and administrative services agreement, dated as of April 9, 2018, or the FS/EIG investment advisory agreement. FS/EIG Advisor oversees the management of the Company’s operations and is responsible for making investment decisions with respect to the Company’s portfolio. FS/EIG Advisor is jointly operated by an affiliate of Franklin Square Holdings, L.P. (which does business as FS Investments) and EIG Asset Management, LLC, or EIG.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
Summary of Significant Accounting Policies	Mar. 31, 2024
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation: The accompanying unaudited consolidated financial statements of the Company have been prepared in accordance with accounting principles generally accepted in the United States of America, or GAAP, for interim financial information and with the instructions for Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included. For a more complete discussion of significant accounting policies and certain other information, the Company’s interim unaudited consolidated financial statements should be read in conjunction with its audited consolidated financial statements as of and for the year ended December 31, 2023 included in the Company’s annual report on Form 10-K. Operating results for the three months ended March 31, 2024 are not necessarily indicative of the results that may be expected for the year ending December 31, 2024. The December 31, 2023 consolidated balance sheet and consolidated schedule of investments are derived from the Company's audited consolidated financial statements as of and for the year ended December 31, 2023. The Company is considered an investment company under GAAP and follows the accounting and reporting guidance applicable to investment companies under Accounting Standards Codification Topic 946, Financial Services—Investment Companies. The Company has evaluated the impact of subsequent events through the date the unaudited consolidated financial statements were issued and filed with the Securities and Exchange Commission, or the SEC. Use of Estimates: The preparation of the unaudited consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Many of the amounts have been rounded, and all amounts are in thousands, except share and per share amounts. Capital Gains Incentive Fee: Pursuant to the terms of the FS/EIG investment advisory agreement, the incentive fee on capital gains is determined and payable in arrears as of the end of each calendar year (or upon termination of such agreement). Such fee equals 20.0% of the Company’s “incentive fee capital gains,” which are the Company’s realized capital gains on a cumulative basis from inception, calculated as of the end of the applicable period, computed net of all realized capital losses and unrealized capital depreciation on a cumulative basis, less the aggregate amount of any previously paid incentive fees on capital gains. The Company will accrue for the incentive fee on capital gains, which, if earned, will be paid annually. The Company will accrue the incentive fee on capital gains based on net realized and unrealized gains; however, the fee payable to FS/EIG Advisor will be based on realized gains and no such fee will be payable with respect to unrealized gains unless and until such gains are actually realized. For the three months ended March 31, 2024 and 2023, the Company did not accrue any amount of capital gains incentive fee. Subordinated Income Incentive Fee: Pursuant to the terms of the FS/EIG investment advisory agreement, FS/EIG Advisor may also be entitled to receive a subordinated incentive fee on income. The subordinated incentive fee on income under the FS/EIG investment advisory agreement is calculated and payable quarterly in arrears and equals 20.0% of the Company’s “pre-incentive fee net investment income” for the immediately preceding quarter subject to a hurdle rate, expressed as a rate of return on adjusted capital, equal to 1.625% per quarter, or an annualized hurdle rate of 6.5%. As a result, FS/EIG Advisor will not earn this incentive fee for any quarter until the Company’s pre-incentive fee net investment income for such quarter exceeds the hurdle rate of 1.625%. For purposes of this fee, “adjusted capital” means cumulative gross proceeds generated from sales of the Company’s common shares (including proceeds from its distribution reinvestment plan) reduced for distributions from non-liquidating dispositions of the Company’s investments paid to shareholders and amounts paid for share repurchases pursuant to the Company’s share repurchase program. Once the Company’s pre-incentive fee net investment income in any quarter exceeds the hurdle rate, FS/EIG Advisor will be entitled to a “catch-up” fee equal to the amount of the Company’s pre-incentive fee net investment income in excess of the hurdle rate, until the Company’s pre-incentive fee net investment income for such quarter equals 2.031%, or 8.125% annually, of adjusted capital. This “catch-up” feature will allow FS/EIG Advisor to recoup the fees foregone as a result of the existence of the hurdle rate. Thereafter, FS/EIG Advisor will be entitled to receive 20.0% of the Company’s pre-incentive fee net investment income. For the three months ended March 31, 2024 and 2023, the Company did not accrue any amount of subordinated incentive fee on income. Reclassifications: Certain amounts in the unaudited consolidated financial statements for the three months ended March 31, 2023 may have been reclassified to conform to the classifications used to prepare the unaudited consolidated financial statements for the three months ended March 31, 2024. Revenue Recognition: Security transactions are accounted for on the trade date. The Company records interest income on an accrual basis to the extent that it expects to collect such amounts. The Company records dividend income on the ex-dividend date. Distributions received from limited liability company, or LLC, and limited partnership, or LP, investments are evaluated to determine if the distribution should be recorded as dividend income or a return of capital. The Company does not accrue as a receivable interest or dividends on loans and securities if it has reason to doubt its ability to collect such income. The Company’s policy is to place investments on non-accrual status when there is reasonable doubt that interest income will be collected. The Company considers many factors relevant to an investment when placing it on or removing it from non-accrual status including, but not limited to, the delinquency status of the investment, economic and business conditions, the overall financial condition of the underlying investment, the value of the underlying collateral, bankruptcy status, if any, and any other facts or circumstances relevant to the investment. If there is reasonable doubt that the Company will receive any previously accrued interest, then the accrued interest will be written-off. Payments received on non-accrual investments may be recognized as income or applied to principal depending upon the collectability of the remaining principal and interest. Non-accrual investments may be restored to accrual status when principal and interest become current and are likely to remain current based on the Company’s judgment. Loan origination fees, original issue discount and market discount are capitalized and the Company amortizes such amounts as interest income over the respective term of the loan or security. Upon the prepayment of a loan or security, any unamortized loan origination fees and original issue discount are recorded as interest income. Structuring and other non-recurring upfront fees are recorded as fee income when earned. The Company records prepayment premiums on loans and securities as fee income when it earns such amounts. For the three months ended March 31, 2024 and 2023, the Company recognized no structuring or other upfront fee revenue. Derivative Instruments: The Company’s derivative instruments may include fixed price swaps and equity total return swaps. The Company recognizes all derivative instruments as assets or liabilities at fair value in its consolidated financial statements. Derivative contracts entered into by the Company are not designated as hedging instruments for accounting purposes, and as a result, the Company presents changes in fair value through net change in unrealized appreciation (depreciation) on swap contracts in the consolidated statements of operations. Realized gains and losses of the derivative instruments are included in net realized gain (loss) on swap contracts in the consolidated statements of operations. Collateralized Loan Obligation – Warehouses: A Collateralized Loan Obligation Warehouse, or CLO Warehouse, is an entity organized for the purpose of holding syndicated bank loans, also known as leveraged loans, prior to the issuance of securities from that same vehicle. During the warehouse period, a CLO Warehouse will secure investments and build a portfolio of primarily leveraged loans and other debt obligations. The warehouse period terminates when the collateralized loan obligation vehicle issues various tranches of securities to the market. At this time, financing through the issuance of debt securities and subordinated notes is used to repay the bank financing. The fair value of the Company’s investment in the CLO Warehouse is determined by adding the excess spread (accrued interest plus interest received less financing cost) to the Company’s initial investment in the CLO Warehouse. Consistent with Accounting Standards Codification Topic 820, Fair Value Measurements and Disclosure , or ASC Topic 820, issued by the Financial Accounting Standards Board, or the FASB, the excess spread represents the price that would be received from the sale of the CLO Warehouse investment in an orderly transaction between market participants. CLO warehouses can be exposed to credit events, mark to market changes, rating agency downgrades and financing cost changes. Recent Accounting Pronouncements: In June 2022, the FASB issued Accounting Standards Update No. 2022-03, Fair Value Measurement (Topic 820): Fair Value Measurement of Equity Securities Subject to Contractual Sale Restrictions , or ASU 2022-03, which clarifies guidance for fair value measurement of an equity security subject to a contractual sale restriction and establishes new disclosure requirements for such equity securities. ASU 2022-03 is effective for fiscal years beginning after December 15, 2023 and for interim periods within those fiscal years, with early adoption permitted. The Company has concluded that this guidance did not have a material impact on its consolidated financial statements.

Share Transactions

Share Transactions	3 Months Ended
Share Transactions	Mar. 31, 2024
Equity [Abstract]
Share Transactions	Share Transactions Below is a summary of transactions with respect to the Company’s common shares during the three months ended March 31, 2024 and 2023: Three Months Ended 2024 2023 Shares Amount Shares Amount Reinvestment of Distributions (1) — $ — 1,321,335 $ 5,218 Proceeds from Share Transactions — $ — 1,321,335 $ 5,218 ______________ (1) On September 15, 2023, the Company's second amended and restated distribution reinvestment plan terminated. On July 19, 2023, the Company’s board of trustees, including the independent trustees, approved the termination of the Company’s second amended and restated distribution reinvestment plan with respect to distributions declared by the Company’s board of trustees on the Company’s common shares, effective as of September 15, 2023. After this date, all shareholders will receive any subsequent distributions in cash. On February 25, 2020, the Company received exemptive relief from the SEC permitting it to offer multiple classes of common shares. While the Company has no present intention to recommence a public offering of its common shares, the Company could do so in the future. Share Repurchase Program In March 2020, in light of difficult market conditions and in an effort to preserve liquidity in the Company, the Company’s board of trustees determined to suspend for an indefinite period of time the Company’s share repurchase program and will reassess the Company’s ability to recommence such program in future periods. Prior to its suspension, the Company intended to conduct quarterly tender offers pursuant to its share repurchase program. The Company's board of trustees will consider the following factors, among others, in making its determination regarding whether to cause the Company to offer to repurchase common shares and under what terms: • the effect of such repurchases on the Company’s qualification as a RIC (including the consequences of any necessary asset sales); • the liquidity of the Company's assets (including fees and costs associated with disposing of assets); • the Company’s investment plans and working capital requirements; • the relative economies of scale with respect to the Company’s size; • the Company’s history in repurchasing common shares or portions thereof; and • the condition of the securities markets. On May 5, 2017, the board of trustees of the Company further amended the share repurchase program. As amended, the Company limited the maximum number of common shares to be repurchased for any repurchase offer to the greater of (A) the number of common shares that the Company can repurchase with the proceeds it has received from the sale of common shares under its distribution reinvestment plan during the twelve-month period ending on the date the applicable repurchase offer expires (less the amount of proceeds used to repurchase common shares on each previous repurchase date for repurchase offers conducted during such twelve-month period) (this limitation is referred to as the twelve-month repurchase limitation) and (B) the number of common shares that the Company can repurchase with the proceeds the Company receives from the sale of common shares under its distribution reinvestment plan during the three-month period ending on the date the applicable repurchase offer expires (this limitation is referred to as the three-month repurchase limitation). In addition to this limitation, the maximum number of common shares to be repurchased for any repurchase offer has also been limited to 10% of the weighted average number of common shares outstanding in the prior calendar year, or 2.5% in each calendar quarter. As a result, the maximum number of common shares to be repurchased for any repurchase offer would not exceed the lesser of (i) 10% of the weighted average number of common shares outstanding in the prior calendar year, or 2.5% in each calendar quarter, and (ii) whichever is greater of the twelve-month repurchase limitation described in clause (A) above and the three-month repurchase limitation described in clause (B) above. Historically, pursuant to the Company's share repurchase program, the Company offered to repurchase common shares at a price equal to the price at which common shares were issued pursuant to the Company’s distribution reinvestment plan on the distribution date coinciding with the applicable share repurchase date. The price at which common shares were issued under the Company’s distribution reinvestment plan was determined by the Company’s board of trustees or a committee thereof, in its sole discretion, and was (i) not less than the net asset value per common share as determined in good faith by the Company’s board of trustees or a committee thereof, in its sole discretion, immediately prior to the payment date of the distribution and (ii) not more than 2.5% greater than the net asset value per common share as of such date. The Company’s board of trustees may amend, suspend or terminate the share repurchase program at any time, upon 30 days’ notice. The Company did not repurchase any shares pursuant to its share repurchase program during the three months ended March 31, 2024 and 2023. The Company's distribution reinvestment plan was terminated effective September 15, 2023. In order to minimize the expense of supporting small accounts and provide additional liquidity to shareholders of the Company holding small accounts after completion of a regular quarterly share repurchase offer, the Company reserves the right to repurchase the shares of and liquidate any investor’s account if the balance of such account is less than the Company’s $5 minimum initial investment, unless the account balance has fallen below the minimum solely as a result of a decline in the Company’s net asset value per share. The Company will provide or will cause to be provided 30 days’ prior written notice to potentially affected investors, which notice may be included in regular quarterly repurchase offer materials, of any such repurchase. Historically, any such repurchases were made at the Company’s most recent price at which the Company’s shares were issued pursuant to its distribution reinvestment plan. There were no de minimis account liquidations during the three months ended March 31, 2024 and 2023.

Related Party Transactions

Related Party Transactions	3 Months Ended
Related Party Transactions	Mar. 31, 2024
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions Compensation of the Investment Adviser Pursuant to the FS/EIG investment advisory agreement, FS/EIG Advisor is entitled to an annual base management fee based on the average weekly value of the Company’s gross assets (gross assets equals total assets as set forth on the Company’s consolidated balance sheets) during the most recently completed calendar quarter and an incentive fee based on the Company’s performance. The base management fee is payable quarterly in arrears, and is calculated at an annual rate of 1.75% of the average weekly value of the Company’s gross assets. See Note 2 for a discussion of the capital gains and subordinated income incentive fees that FS/EIG Advisor may be entitled to under the FS/EIG investment advisory agreement. FS/EIG Advisor may receive structuring or other upfront fees from portfolio companies in which FS/EIG Advisor has caused the Company to invest. FS/EIG Advisor has agreed to offset the amount of any structuring, upfront or certain other fees received by FS/EIG Advisor or its members against the management fees payable by the Company under the FS/EIG investment advisory agreement. During the three months ended March 31, 2023, $255 of structuring, upfront or certain other fees received by FS/EIG Advisor or its members were offset against management fees. There were no fees offset during the three months ended March 31, 2024. Pursuant to the FS/EIG investment advisory agreement, FS/EIG Advisor oversees the Company’s day-to-day operations, including the provision of general ledger accounting, fund accounting, legal services, investor relations, certain government and regulatory affairs activities and other administrative services. FS/EIG Advisor also performs, or oversees the performance of, the Company’s corporate operations and required administrative services, which includes being responsible for the financial records that the Company is required to maintain and preparing reports for the Company’s shareholders and reports filed with the SEC. The Company reimburses FS/EIG Advisor for expenses necessary to perform services related to the Company’s administration and operations, including FS/EIG Advisor’s allocable portion of the compensation and/or related expenses of certain personnel of FS Investments and EIG providing administrative services to the Company on behalf of FS/EIG Advisor, and for transactional expenses for prospective investments, such as fees and expenses associated with performing due diligence reviews of investments that do not close, often referred to as “broken deal” costs. The Company reimburses FS/EIG Advisor no less than quarterly for expenses necessary to perform services related to the Company’s administration and operations. The amount of this reimbursement is set at the lesser of (1) FS/EIG Advisor’s actual costs incurred in providing such services and (2) the amount that the Company estimates it would be required to pay alternative service providers for comparable services in the same geographic location. FS/EIG Advisor allocates the cost of such services to the Company based on factors such as time allocations and other reasonable metrics. The Company’s board of trustees reviews the methodology employed in determining how the expenses are allocated to the Company and assesses the reasonableness of such reimbursements for expenses allocated to the Company based on the breadth, depth and quality of such services as compared to the estimated cost to the Company of obtaining similar services from third-party providers known to be available. In addition, the Company’s board of trustees considers whether any single third-party service provider would be capable of providing all such services at comparable cost and quality. Finally, the Company’s board of trustees, among other things, compares the total amount paid to FS/EIG Advisor for such services as a percentage of the Company’s net assets to the same ratio as reported by other comparable BDCs. The Company does not reimburse FS/EIG Advisor for any services for which it receives a separate fee, or for rent, depreciation, utilities, capital equipment or other administrative items allocated to a controlling person of FS/EIG Advisor. The following table describes the fees and expenses accrued under the FS/EIG investment advisory agreement during the three months ended March 31, 2024 and 2023: Three Months Ended Related Party Source Agreement Description 2024 2023 FS/EIG Advisor FS/EIG investment advisory agreement Base Management Fee (1) $ 9,112 $ 10,219 FS/EIG Advisor FS/EIG investment advisory agreement Administrative Services Expenses (2) $ 1,535 $ 1,320 _________________________ (1) During the three months ended March 31, 2024 and 2023, $8,416 and $11,185, respectively, in base management fees were paid to FS/EIG Advisor. The base management fee amount shown in the table above is shown net of $255 in structuring, upfront or certain other fees received by FS/EIG Advisor or its members and offset against base management fees for the three months ended March 31, 2023. There were no fees offset during the three months ended March 31, 2024. As of March 31, 2024 , $9,112 in base management fees were payable to FS/EIG Advisor. (2) During the three months ended March 31, 2024 and 2023, $733 and $645, respectively, of the accrued administrative services expenses related to the allocation of costs of administrative personnel for services rendered to the Company by FS/EIG Advisor and the remainder related to other reimbursable expenses. The Company paid $1,149 and $1,458 in administrative services expenses to FS/EIG Advisor, or its affiliates, during the three months ended March 31, 2024 and 2023, respectively. Potential Conflicts of Interest The members of the senior management and investment teams of FS/EIG Advisor serve or may serve as officers, directors or principals of entities that operate in the same or a related line of business as the Company does, or of investment vehicles managed by the same personnel. The officers, managers and other personnel of FS/EIG Advisor may serve in similar or other capacities for the investment advisers to future investment vehicles affiliated with FS Investments or EIG. In serving in these multiple and other capacities, they may have obligations to other clients or investors in those entities, the fulfillment of which may not be in the Company’s best interests or in the best interest of the Company’s shareholders. The Company’s investment objectives may overlap with the investment objectives of such investment funds, accounts or other investment vehicles. For additional information regarding potential conflicts of interest, see the Company’s annual report on Form 10-K for the year ended December 31, 2023. Exemptive Relief As a BDC, the Company is subject to certain regulatory restrictions in making its investments. For example, BDCs generally are not permitted to co-invest with certain affiliated entities in transactions originated by the BDC or its affiliates in the absence of an exemptive order from the SEC. However, BDCs are permitted to, and may, simultaneously co-invest in transactions where price is the only negotiated term. In an order dated June 4, 2013, or the Order, the SEC granted exemptive relief permitting the Company, subject to the satisfaction of certain conditions, to co-invest in certain privately negotiated investment transactions with certain affiliates of its former investment adviser, including FS KKR Capital Corp., or collectively the Company’s co-investment affiliates. Effective April 9, 2018, or the JV Effective Date, and in connection with the transition of advisory services to a joint advisory relationship with EIG, the Company’s board of trustees authorized and directed that the Company (i) withdraw from the Order, except with respect to any transaction in which the Company participated in reliance on the Order prior to the JV Effective Date, and (ii) rely on an exemptive relief order dated April 10, 2018, granted to EIG and its affiliates which permits the Company to participate in co-investment transactions with certain other EIG advised funds, or the EIG Order. On September 19, 2023, the Company, among other applicants, filed an application with the SEC to seek permission to co-invest in certain privately negotiated transactions with certain affiliates of FS/EIG Advisor, including FS Credit Opportunities Corp. and FS Tactical Opportunities Fund. The application provides that, among other things, should the SEC grant the requested order, the Company would withdraw from the EIG Order, except with respect to any transaction in which the Company participated in reliance on the EIG Order prior to the issuance of the new order. There is no guarantee if and when the application will be granted by the SEC. Bridge Street Warehouse CLO IV Ltd. Bridge Street Warehouse CLO IV Ltd., or Bridge Street Warehouse CLO IV, is a CLO Warehouse in which the residual subordinated notes are fully held by the Company, which is accounted for as a financial instrument at fair value as of March 31, 2024. Bridge Street Warehouse CLO IV commenced operations on January 26, 2024 and was in the warehouse phase as of March 31, 2024. As of March 31, 2024, the Company contributed $20,000 and had an unfunded commitment of $20,000 to contribute capital to Bridge Street Warehouse CLO IV. The Company had an investment of $20,329 in Bridge Street Warehouse CLO IV, at fair value, as of March 31, 2024. Bridge Street Warehouse CLO IV financed the majority of its loan purchases using its warehouse financing facility. The amount of interest income from the Bridge Street Warehouse CLO IV recorded on the Company’s unaudited consolidated statement of operations for the three months ended March 31, 2024 was approximately $329. On April 18, 2024, the Company contributed $2,000 to Bridge Street Warehouse CLO IV. On April 26, 2024, the CLO Warehouse phase terminated when Bridge Street Warehouse CLO IV merged with and into the collateralized loan obligation vehicle, Bridge Street CLO IV Ltd., or Bridge Street CLO IV, and substantially simultaneously therewith, Bridge Street CLO IV issued to the market various tranches of debt (including notes and loans) in the aggregate principal amount of $354,700, including $23,700 principal amount of subordinated notes to the Company. Bridge Street CLO IV's collateral manager also has agreed to reimburse the Company for collateral management fees. Proceeds from the CLO debt issuance were used to repay the warehouse financing facility.

Distributions

Distributions	3 Months Ended
Distributions	Mar. 31, 2024
Income Tax Disclosure [Abstract]
Distributions	Distributions The following table reflects the cash distributions per share that the Company declared on its common shares during the three months ended March 31, 2024 and 2023: Distribution For the Three Months Ended Per Share Amount Fiscal 2023 March 31, 2023 $ 0.0300 $ 13,584 Fiscal 2024 March 31, 2024 (1) $ 0.0034 $ 1,549 _________________________ (1) For the quarter ended December 31, 2023, the distribution amount per share was $0.0643, comprised of an initial distribution per share of $0.0609 declared in December 2023 and the remaining distribution per share of $0.0034 declared in January 2024, collectively representing an annualized distribution rate to shareholders of 7.5%. Subject to applicable legal restrictions and the sole discretion of the Company's board of trustees, the Company expects to provide enhanced quarterly distributions to shareholders until the achievement of a long-term liquidity event. On April 18, 2024, the Company's board of trustees declared an enhanced cash distribution of $0.0866 per share for the first quarter of 2024, representing an annualized distribution rate to shareholders of 10.0% based on the estimated net asset value of $3.47 per share as of March 31, 2024. The enhanced distributions are expected to be paid quarterly and increase in subsequent years until the achievement of a long-term liquidity event, subject to a maximum cap of 15.0% of the Company’s then-current estimated net asset value beyond 2026. The Company expects a portion of the distributions may represent a return of investor capital, helping to accelerate liquidity for shareholders in the near-term. There can be no assurance that the Company will be able to pay distributions in the future. The timing and amount of any future distributions to shareholders are subject to applicable legal restrictions and the sole discretion of the Company’s board of trustees. Historically, the Company had an “opt in” distribution reinvestment plan for its shareholders. As a result, if the Company made a cash distribution, its shareholders would receive distributions in cash unless they specifically “opted in” to the distribution reinvestment plan so as to have their cash distributions reinvested in additional common shares. However, certain state authorities or regulators may have imposed restrictions from time to time that may have prevented or limited a shareholder's ability to participate in the distribution reinvestment plan. The Company's distribution reinvestment plan was terminated effective as of September 15, 2023. Under the prior distribution reinvestment plan, cash distributions to participating shareholders would be reinvested in additional common shares at a purchase price determined by the Company’s board of trustees, or a committee thereof, in its sole discretion, that was (i) not less than the net asset value per common share as determined in good faith by the Company’s board of trustees or a committee thereof, in its sole discretion, immediately prior to the payment of the distribution and (ii) not more than 2.5% greater than the net asset value per common share as of such date. Any distributions reinvested under the plan would remain taxable to a U.S. shareholder. The Company may fund its cash distributions to shareholders from any sources of funds legally available to it, including proceeds from the sale of the Company’s common shares, borrowings, net investment income from operations, capital gains proceeds from the sale of assets and non-capital gains proceeds from the sale of assets, dividends or other distributions paid to the Company on account of preferred and common equity investments in portfolio companies. The Company has not established limits on the amount of funds it may use from available sources to make distributions. The Company's distribution proceeds have exceeded and in the future may exceed its earnings. Therefore, portions of the distributions that the Company has made represented, and may make in the future may represent, a return of capital to shareholders, which lowers their tax basis in their common shares. A return of capital generally is a return of a shareholder’s investment rather than a return of earnings or gains derived from the Company’s investment activities. Each year a statement on Form 1099-DIV identifying the sources of the distributions (i.e., paid from ordinary income, paid from net capital gains on the sale of securities, and/or a return of capital, which is a nontaxable distribution) will be mailed to the Company’s shareholders. There can be no assurance that the Company will be able to pay distributions at a specific rate or at all. The following table reflects the sources of the cash distributions on a tax basis that the Company declared on its common shares during the three months ended March 31, 2024 and 2023: Three Months Ended 2024 2023 Source of Distribution Distribution Amount Percentage Distribution Amount Percentage Net investment income (1) $ 1,549 100 % $ 13,584 100 % Short-term capital gains proceeds from the sale of assets — — — — Long-term capital gains proceeds from the sale of assets — — — — Total $ 1,549 100 % $ 13,584 100 % _________________________ (1) During the three months ended March 31, 2024 and 2023, 94.5% and 86.6%, respectively, of the Company's gross investment income was attributable to cash income earned, 2.4% and 10.5%, respectively, was attributable to paid-in-kind, or PIK, interest and 3.1% and 2.9%, respectively, was attributable to non-cash accretion of discount. The determination of the tax attributes of the Company’s distributions is made annually as of the end of the Company’s fiscal year based upon the Company’s taxable income for the full year and distributions paid for the full year. Therefore, a determination made on a quarterly basis may not be representative of the actual tax attributes of the Company's distributions for a full year. The actual tax characteristics of distributions to shareholders are reported to shareholders annually on Form 1099-DIV. Net capital losses may be carried forward indefinitely, and their character is retained as short-term or long-term. As of March 31, 2024, the Company had short-term and long-term capital loss carryforwards available to offset future realized capital gains of $73,711 and $1,518,431, respectively. As of March 31, 2024 and December 31, 2023, for federal income tax purposes, the gross unrealized appreciation on the Company’s investments, swap contracts and unrealized gain on foreign currency was $135,476 and $148,817, respectively, and the gross unrealized depreciation on the Company’s investments, swap contracts and unrealized loss on foreign currency was $235,643 and $213,339, respectively. The aggregate cost of the Company’s investments for federal income tax purposes totaled $1,901,617 and $1,587,709 as of March 31, 2024 and December 31, 2023, respectively. The aggregate net unrealized appreciation (depreciation) on a tax basis was $(100,345) and $(64,513) as of March 31, 2024 and December 31, 2023, respectively.

Financial Instruments

Financial Instruments	3 Months Ended
Financial Instruments	Mar. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Financial Instruments	Financial Instruments The Company may trade in financial instruments with off-balance sheet risk in the normal course of its investing activities. Fixed Price Swaps The Company previously utilized commodity fixed price swaps to economically hedge certain risks against natural gas and crude oil price exposure related to certain investments in the Company's portfolio. A fixed price swap is a contract between two parties in which settlements are made at a specified time based on the difference between the fixed price specified in the contract and the referenced settlement price. When the referenced settlement price was less than the price specified in the contract, the Company received an amount from the counterparty based on the price difference multiplied by the volume. Similarly, when the referenced settlement price exceeded the price specified in the contract, the Company paid the counterparty an amount based on the price difference multiplied by the volume. The Company's fixed price swaps were settled monthly and the settlement prices contained in these fixed price swaps were based on commodity exchanges; the NYMEX Henry Hub for natural gas and the ICE Brent for oil. Gas volumes are measured in one million British thermal units, or MMBtus, and oil volumes are measured in barrels, or Bbls. The changes in the value of the fixed price swaps were recorded as unrealized appreciation or depreciation on swap contracts in the consolidated balance sheets. The Company's fixed price swaps settled monthly and the changes in the value of the fixed price swaps were recorded as realized gains or losses in the consolidated statements of operations. The primary underlying risk exposure through the use of fixed price swaps is commodity price risk of the underlying commodity, such as natural gas and crude oil. As of December 31, 2023, the Company's fixed price swaps were fully terminated. Total Return Swaps The Company utilizes total return swaps to obtain exposure to securities without owning such securities. A total return swap, or TRS, is a contract in which there is an exchange of cash flows whereby one party agrees to make periodic payments based on the total return (distributions or periodic interest payments plus capital gains/losses) of an underlying instrument in exchange for fixed or floating rate interest payments. If the total return of the instrument or index underlying the transaction exceeds or falls short of the offsetting fixed or floating interest rate obligation, the Company receives payment from or makes a payment to the counterparty. Total return swaps are entered into to obtain exposure to a security or market without owning such security or investing directly in such market or to exchange the risk/return of one market with another market. Nomura Total Return Swap On September 20, 2023, the Company entered into an equity total return swap with Nomura Global Financial Products Inc., or Nomura. Under the Nomura TRS, the Company obtains the economic benefit of owning shares of FS Credit Opportunities Corp., or FSCO, an investment company registered under the 1940 Act, without actually owning them, and Nomura receives an interest-type payment in return. The investment adviser to FSCO is wholly-owned by Franklin Square Holdings, L.P., which is also the majority owner of FS/EIG Advisor. The Nomura TRS is marked-to-market daily and the change in market value is recorded as unrealized appreciation or depreciation on swap contracts in the consolidated balance sheets. Pursuant to its terms, the Nomura TRS settles monthly and a realized gain or loss is recorded in the consolidated statements of operations equal to the difference between the value of the shares underlying the Nomura TRS at the time the swap was entered into or the previous settlement date and the value as of the current settlement date, plus dividends received and less accrued interest. Any dividends received by Nomura as holder of the FSCO shares are paid to the Company. The Nomura TRS has a term of three years, but it could be terminated earlier in whole or in part following the occurrence of certain prescribed events agreed to between Nomura and the Company. The primary underlying risk exposure through the use of equity total return swaps is equity market risk. BNP Paribas Total Return Swap On February 15, 2024, FSSL Finance BNPP TRS LLC, or FSSL Finance BNPP TRS, a wholly-owned financing subsidiary of the Company, entered into a TRS for a portfolio of senior secured floating rate loans with BNP Paribas, or BNPP. The BNPP TRS enables the Company, through its ownership of FSSL Finance BNPP TRS, to obtain the economic benefit of owning the broadly syndicated loans subject to the TRS, without actually owning them, in return for an interest-type payment to BNPP. As such, the BNPP TRS is analogous to the Company borrowing funds to acquire loans and incurring interest expense to a lender. The terms of the BNPP TRS include, among other things, (a) payment by BNPP to FSSL Finance BNPP TRS of all interest and fees (less applicable withholding taxes) on the underlying loans, (b) payment by FSSL Finance BNPP TRS to BNPP of (i) a financing fee on the outstanding notional amount of the TRS at a rate equal to USD-SOFR Compounded Index plus 1.65% per annum, and (ii) a utilization fee of 0.85% per annum on the difference between any lesser usage amount and a $100,000 minimum usage threshold, (c) upon the termination or repayment of any loan subject to the TRS, FSSL Finance BNPP TRS either will receive from BNPP the appreciation in the value of such loan or will pay to BNPP any depreciation in the value of such loan and (d) guarantee by the Company of all obligations of FSSL Finance BNPP TRS. During the three months ended March 31, 2024, the monthly average notional amounts of the Nomura TRS and the BNPP TRS were $38,984 and $52,462, respectively. The following table presents the fair value of open swap contracts (which are not considered to be hedging instruments for accounting purposes) as of March 31, 2024 and December 31, 2023: March 31, 2024 December 31, 2023 Instrument Asset (1) Liability Asset Liability Nomura Total Return Swap $ — $ — $ — $ — BNP Paribas Total Return Swap 196 — — — Total $ 196 $ — $ — $ — ______________ (1) Reflected on the Company's consolidated balance sheets as: Unrealized appreciation on swap contracts. The effect of swap contracts (which are not considered to be hedging instruments for accounting purposes) on the Company's statements of operations for the three months ended March 31, 2024 and 2023 were as follows: Net Realized Gains (Losses) (1) Net Change in Unrealized (2) Three Months Ended Three Months Ended Instrument 2024 2023 2024 2023 Commodity Fixed Price Swaps—Crude Oil $ — $ (100) $ — $ 733 Commodity Fixed Price Swaps—Natural Gas — 112 — 344 Nomura Total Return Swap 2,302 — — — BNP Paribas Total Return Swap 25 — 196 — Total $ 2,327 $ 12 $ 196 $ 1,077 ______________ (1) Reflected on the Company's consolidated statements of operations as: Net realized gain (loss) on swap contracts. (2) Reflected on the Company's consolidated statements of operations as: Net change in unrealized appreciation (depreciation) on swap contracts. Offsetting of Derivative Instruments The Company has derivative instruments that are subject to master netting agreements. These agreements include provisions to offset positions with the same counterparty in the event of default by one of the parties. The Company’s unrealized appreciation and depreciation on derivative instruments are reported as gross assets and liabilities, respectively, in the consolidated balance sheets. The following table presents the Company’s derivative assets and liabilities by counterparty, net of amounts available for offset under a master netting agreement and net of any collateral received or pledged by the Company for such assets and liabilities as of March 31, 2024: As of March 31, 2024 Counterparty Derivative Assets Derivative Liabilities Net Value of Derivatives Non-Cash Collateral (Received) Pledged (1) Cash Collateral (Received) Pledged (1) Net Amount of Derivative Assets (Liabilities) (2) BNP Paribas $ 196 — $ 196 — — $ 196 ______________ (1) In some instances, the actual amount of the collateral received and/or pledged may be more than the amount shown due to overcollateralization. (2) Net amount of derivative assets and liabilities represents the net amount due from the counterparty to the Company and the net amount due from the Company to the counterparty, respectively, in the event of default.

Investment Portfolio

Investment Portfolio	3 Months Ended
Investment Portfolio	Mar. 31, 2024
Schedule of Investments [Abstract]
Investment Portfolio	Investment Portfolio The following table summarizes the composition of the Company’s investment portfolio at cost and fair value as of March 31, 2024 and December 31, 2023: March 31, 2024 December 31, 2023 Amortized Cost (1) Fair Value Percentage Amortized Cost (1) Fair Value Percentage Senior Secured Loans—First Lien $ 1,031,295 $ 962,663 53 % $ 878,013 $ 825,158 54 % Senior Secured Loans—Second Lien 81,646 81,936 5 % 55,064 54,424 4 % Senior Secured Bonds 96,035 98,436 6 % 82,793 84,468 5 % Asset Based Finance 20,329 20,329 1 % — — — Preferred Equity 246,345 324,731 18 % 252,450 259,990 17 % Sustainable Infrastructure Investments, LLC 43,150 40,830 2 % 43,150 39,427 3 % Equity/Other 211,451 145,522 8 % 211,461 238,729 16 % Short-Term Investments 126,763 126,825 7 % 20,994 21,000 1 % Total $ 1,857,014 $ 1,801,272 100 % $ 1,543,925 $ 1,523,196 100 % ______________ (1) Amortized cost represents the original cost adjusted for the amortization of premiums and/or accretion of discounts, as applicable, on investments. In general, under the 1940 Act, the Company would be presumed to “control” a portfolio company if it owned more than 25% of its voting securities or it had the power to exercise control over the management or policies of a portfolio company, and would be an “affiliated person” of a portfolio company if it owned 5% or more of its voting securities. As of March 31, 2024, the Company held investments in five portfolio companies of which it is deemed to be an “affiliated person” but is not deemed to “control” and held investments in three portfolio companies of which it is deemed to “control.” For additional information with respect to such portfolio companies, see footnotes (t) and (u) to the unaudited consolidated schedule of investments as of March 31, 2024 in this quarterly report on Form 10-Q. As of December 31, 2023, the Company held investments in four portfolio companies of which it is deemed to be an “affiliated person” but is not deemed to “control” and held investments in three portfolio companies of which it is deemed to “control.” For additional information with respect to such portfolio companies, see footnotes (u) and (v) to the consolidated schedule of investments as of December 31, 2023 in this quarterly report on Form 10-Q. The Company’s investment portfolio may contain loans or bonds that are in the form of lines of credit or revolving credit facilities, or other investments, pursuant to which the Company may be required to provide funding when requested by portfolio companies in accordance with the terms of the underlying agreements. As of March 31, 2024, the Company had six senior secured loan investments with aggregate unfunded commitments of $14,996 and unfunded commitments of $18,989 in U.S. dollars and $858 in Canadian dollars to contribute capital to Sustainable Infrastructure Investments, LLC. As of December 31, 2023, the Company had five senior secured loan investments with aggregate unfunded commitments of $11,232 and unfunded commitments of $18,989 in U.S dollars and $858 in Canadian dollars to contribute capital to Sustainable Infrastructure Investments, LLC. The Company maintains sufficient cash on hand, available borrowings and/or liquid securities to fund such unfunded commitments should the need arise. The table below describes investments by industry classification and enumerates the percentage, by fair value, of the total portfolio assets in such industries as of March 31, 2024 and December 31, 2023: March 31, 2024 December 31, 2023 Industry Classification Fair Value Percentage Fair Value Percentage Energy—Midstream $ 354,759 20 % $ 303,175 20 % Energy—Upstream 214,120 12 % 309,456 20 % Consumer Services 190,829 11 % 156,089 10 % Capital Goods 140,295 8 % 116,454 8 % U.S. Treasury 126,825 7 % 21,000 1 % Commercial & Professional Services (1) 100,700 6 % 62,036 4 % Financial Services 90,663 5 % 83,197 6 % Health Care Equipment & Services 90,338 5 % 73,105 5 % Consumer Discretionary Distribution & Retail 67,022 4 % 37,428 3 % Energy—Power 58,581 3 % 69,696 5 % Materials 55,906 3 % 49,653 3 % Automobiles & Components 49,639 3 % 39,521 3 % Transportation 42,092 2 % 30,157 2 % Household & Personal Products 26,081 1 % 20,858 1 % Insurance 25,269 1 % 20,251 1 % Consumer Durables & Apparel 24,404 1 % — — Consumer Staples Distribution & Retail 24,337 1 % 18,830 1 % Telecommunication Services 19,400 1 % — — Pharmaceuticals, Biotechnology & Life Sciences 19,352 1 % 19,300 1 % Technology Hardware & Equipment 13,685 1 % — — Energy—Service & Equipment (1) 13,629 1 % 33,734 2 % Media & Entertainment 12,516 1 % 19,829 1 % Sustainable Infrastructure Investments, LLC (2) 40,830 2 % 39,427 3 % Total $ 1,801,272 100 % $ 1,523,196 100 % _____________________ (1) FS/EIG Advisor monitors the industry classification of the Company’s investments and may from time to time reclassify such investments if it determines such reclassification is appropriate. During the year ended December 31, 2023, two investments had their industry re-classified from Energy—Industrials to Commercial & Professional Services, and one investment had its industry re-classified from Energy—Service & Equipment to Commercial & Professional Services. (2) Sustainable Infrastructure Investments, LLC is generally comprised of midstream and renewables assets in the Energy sector. Sustainable Infrastructure Investments, LLC Sustainable Infrastructure Investments, LLC, or SIIJV, is a joint venture between the Company and Imperial Sustainable Infrastructure Investments, LLC, or Imperial, a subsidiary of Imperial Capital Asset Management, LLC, or ICAM. The joint venture is governed pursuant to the terms of an amended and restated limited liability company agreement of SIIJV, dated as of January 2, 2020, between the Company and Imperial, or the SIIJV Agreement. The SIIJV Agreement requires the Company and Imperial to provide capital to SIIJV of up to $67,629 in U.S. dollars and $5,430 in Canadian dollars in the aggregate where the Company and Imperial would provide 87.5% and 12.5%, respectively, of the committed capital. Pursuant to the terms of the SIIJV Agreement, the Company and Imperial each have 50% voting control of SIIJV and are required to agree on all investment decisions as well as all other significant actions for SIIJV. SIIJV invests in senior secured loans to middle market companies, broadly syndicated loans and other midstream and renewables assets. As administrative agent of SIIJV, the Company performs certain day-to-day management responsibilities on behalf of SIIJV and is entitled to a fee in the annual amount of 0.25% of SIIJV’s net assets under administration, calculated and payable quarterly in arrears. As of March 31, 2024, the Company and Imperial funded approximately $49,313 to SIIJV, of which $43,150 was from the Company. The Company does not consolidate SIIJV in its consolidated financial statements. On January 2, 2020, Seine Funding, LLC, or Seine Funding, a wholly-owned subsidiary of SIIJV, entered into a credit facility, as amended, or the Seine Funding Facility, with certain financial institutions as lender, agent, collateral agent, collateral administrator, and collateral custodian, and SIIJV, as collateral manager. The Seine Funding Facility provides for borrowings in U.S. dollars and certain agreed upon foreign currencies in an aggregate principal amount of up to $634,103 on a committed basis, which may be increased under certain circumstances at the request of Seine Funding and with the consent of the lender and agent. The end of the reinvestment period for the Seine Funding Facility was on December 31, 2020. The maturity date for the Seine Funding Facility is the earlier of (i) the latest maturity date among the assets securing the facility and (ii) the first date, after the end of the reinvestment period, on which all assets securing the facility are paid in full. Under the Seine Funding Facility, borrowings bear interest at the rate of Term SOFR plus a credit spread adjustment calculated by reference to the interest periods of particular loan assets per the terms of the credit agreement (or the relevant benchmark reference rate for any foreign currency borrowings) (in each case, subject to a floor of the higher of 0% and any applicable floor for particular loan assets), plus 1.20% per annum. Borrowings under the Seine Funding Facility are secured by a first priority security interest in substantially all of the assets of Seine Funding. As of March 31, 2024, total outstanding borrowings under the Seine Funding Facility were $121,041. Below is a summary of SIIJV's portfolio, followed by a listing of the individual loans in SIIJV's portfolio as of March 31, 2024 and December 31, 2023: March 31, 2024 December 31, 2023 Total investments (1) $ 153,837 $ 170,083 Weighted average current interest rate on debt investments (2) 7.41 % 7.45 % Number of portfolio assets in SIIJV 5 6 Largest investment in a single portfolio company (1) $ 57,227 $ 57,227 _____________________ (1) At cost. (2) Computed as the (a) annual stated interest rate on accruing debt, divided by (b) total debt at par amount. Sustainable Infrastructure Investments, LLC Portfolio As of March 31, 2024 (Unaudited) Portfolio Company (a)(b) Energy Industry Rate (c) Maturity Principal Amortized Fair (d) Senior Secured Loans—First Lien—100.0% Blue Heron Intermediate Holdco I, LLC Midstream S+188 4/22/24 $ 30,343 $ 30,343 $ 30,389 Copper Mountain Solar 3, LLC Renewables S+188 5/31/25 16,104 16,104 16,217 FLNG Liquefaction 2, LLC Midstream S+150 12/31/26 26,164 26,164 26,335 NES Hercules Class B Member, LLC Renewables S+163 1/31/28 23,999 23,999 24,473 ST EIP Holdco LLC Midstream S+250 11/5/24 57,227 57,227 57,226 Total Senior Secured Loans—First Lien 153,837 154,640 TOTAL INVESTMENTS—100.0% $ 153,837 $ 154,640 Sustainable Infrastructure Investments, LLC Portfolio As of December 31, 2023 Portfolio Company (a)(b) Energy Industry Rate (c) Maturity Principal Amortized Fair (d) Senior Secured Loans—First Lien—100.0% Blue Heron Intermediate Holdco I, LLC Midstream S+188 4/22/24 $ 30,661 $ 30,661 $ 30,692 Copper Mountain Solar 3, LLC Renewables S+188 5/31/25 16,104 16,104 16,172 FLNG Liquefaction 2, LLC Midstream S+150 12/31/26 26,567 26,567 26,557 NES Hercules Class B Member, LLC Renewables S+163 1/31/28 24,176 24,176 24,769 ST EIP Holdco LLC Midstream S+250 11/5/24 57,227 57,227 57,143 Top of the World Wind Energy LLC Renewables S+213 12/1/28 15,348 15,348 15,616 Total Senior Secured Loans—First Lien 170,083 170,949 TOTAL INVESTMENTS—100.0% $ 170,083 $ 170,949 _____________________ Percentages are shown as a percentage of total investments. (a) Security may be an obligation of one or more entities affiliated with the named company. (b) Security or portion thereof is held within Seine Funding and is pledged as collateral supporting the amounts outstanding under the Seine Funding Facility. (c) Certain variable rate securities in SIIJV's portfolio bear interest at a rate determined by a publicly disclosed base rate plus a basis point spread. As of March 31, 2024 and December 31, 2023, the three-month SOFR, or S, was 5.30% and 5.33%, respectively. SOFR based contracts may include a credit spread adjustment that is charged in addition to the base rate and basis point spread. (d) Security is classified as Level 3 and fair value is determined in accordance with SIIJV’s valuation process. Below is selected balance sheet information for SIIJV as of March 31, 2024 and December 31, 2023: March 31, 2024 December 31, 2023 Selected Balance Sheet Information Total investments, at fair value $ 154,640 $ 170,949 Cash and other assets 20,017 29,089 Total assets $ 174,657 $ 200,038 Debt $ 121,041 $ 145,483 Other liabilities 1,900 3,406 Total liabilities 122,941 148,889 Members' equity $ 51,716 $ 51,149 Below is selected statement of operations information for SIIJV for the three months ended March 31, 2024 and 2023: Three Months Ended 2024 2023 Selected Statement of Operations Information Total investment income $ 3,210 $ 4,798 Expenses Interest expense 2,090 3,141 Administrative services 32 43 Custodian and accounting fees 46 45 Professional services 38 50 Other 10 10 Total expenses 2,216 3,289 Net investment income 994 1,509 Net realized and unrealized gain (loss) (427) 1,946 Net increase (decrease) in net assets resulting from operations $ 567 $ 3,455

Fair Value of Financial Instrum

Fair Value of Financial Instruments	3 Months Ended
Fair Value of Financial Instruments	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Fair Value of Financial Instruments Under existing accounting guidance, fair value is defined as the price that the Company would receive upon selling an investment or pay to transfer a liability in an orderly transaction to a market participant in the principal or most advantageous market for the investment. This accounting guidance emphasizes valuation techniques that maximize the use of observable market inputs and minimize the use of unobservable inputs. Inputs refer broadly to the assumptions that market participants would use in pricing an asset or liability, including assumptions about risk. Inputs may be observable or unobservable. Observable inputs are inputs that reflect the assumptions market participants would use in pricing an asset or liability developed based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the assumptions market participants would use in pricing an asset or liability developed based on the best information available in the circumstances. The Company classifies the inputs used to measure these fair values into the following hierarchy as defined by current accounting guidance: Level 1: Inputs that are quoted prices (unadjusted) in active markets for identical assets or liabilities. Level 2: Inputs that are quoted prices for similar assets or liabilities in active markets. Level 3: Inputs that are unobservable for an asset or liability. A financial instrument’s categorization within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement. As of March 31, 2024 and December 31, 2023, the Company’s investments were categorized as follows in the fair value hierarchy: Valuation Inputs March 31, 2024 December 31, 2023 Level 1—Price quotations in active markets $ — $ — Level 2—Significant other observable inputs 957,057 683,716 Level 3—Significant unobservable inputs 844,215 839,480 Total $ 1,801,272 $ 1,523,196 As of March 31, 2024 and December 31, 2023, the Company’s swap contracts were categorized as follows in the fair value hierarchy: March 31, 2024 December 31, 2023 Valuation Inputs Assets Liabilities Assets Liabilities Level 1—Price quotations in active markets $ — $ — $ — $ — Level 2—Significant other observable inputs 196 — — — Level 3—Significant unobservable inputs — — — — Total $ 196 $ — $ — $ — The Company’s board of trustees is responsible for overseeing the valuation of the Company’s portfolio investments at fair value as determined in good faith pursuant to FS/EIG Advisor’s valuation policy. The Company’s board of trustees has designated FS/EIG Advisor with day-to-day responsibility for implementing the portfolio valuation process set forth in FS/EIG Advisor’s valuation policy. The Company’s investments consist primarily of investments that were acquired directly from the issuer. Debt investments, for which broker quotes or pricing information from third-party pricing services are not generally available, are valued by FS/EIG Advisor with the assistance of independent valuation firms, which determine a valuation range of fair value for such investments by considering, among other factors, the borrower’s ability to adequately service its debt, prevailing interest rates for like investments, call features, anticipated prepayments and other relevant terms of the investments. Except as described below, the Company’s investment in SIIJV and all of the Company’s preferred equity and equity/other investments are also valued by independent valuation firms, which determine the fair value of such investments by considering, among other factors, contractual rights ascribed to such investments, as well as various income scenarios and multiples of earnings before interest, taxes, depreciation and amortization, or EBITDA, cash flows, net income, revenues or, in limited instances, book value, PV-10 multiples or liquidation value. An investment that is newly issued and purchased near the date of the financial statements is valued at cost if FS/EIG Advisor determines that the cost of such investment is the best indication of its fair value. Such investments described above are typically classified as Level 3 within the fair value hierarchy. Investments that are traded on an active public market are valued at their closing price as of the date of the financial statements and are classified as Level 1 within the fair value hierarchy. Except as described above, FS/EIG Advisor typically values the Company’s other investments by using the midpoint of the prevailing bid and ask prices from dealers on the date of the relevant period end, which are provided by an independent third-party pricing service and screened for validity by such service and are typically classified as Level 2 within the fair value hierarchy. In determining the fair values of fixed price swaps, FS/EIG Advisor utilizes an industry-standard pricing model that considers various inputs including quoted forward prices for commodities, time value and current market and contractual prices for the underlying instruments. The fair value of the equity total return swap is determined daily based on the market price of the underlying asset. The fair value of the loan total return swaps is determined daily based on the bid price of the underlying asset provided by the counterparty. These assumptions are observable in the marketplace or can be corroborated by active markets or broker quotes and are typically classified as Level 2 within the fair value hierarchy. FS/EIG Advisor periodically benchmarks the bid and ask prices it receives from the third-party pricing service and/or dealers and independent valuation firms, as applicable, against the actual prices at which the Company purchases and sells its investments. Based on the results of the benchmark analysis and the experience of the Company’s management in purchasing and selling these investments, FS/EIG Advisor believes that these prices are reliable indicators of fair value. FS/EIG Advisor reviewed the valuation determinations made with respect to these investments in a manner consistent with FS/EIG Advisor’s valuation policy. The following is a reconciliation for the three months ended March 31, 2024 and 2023 of investments for which significant unobservable inputs (Level 3) were used in determining fair value: For the Three Months Ended March 31, 2024 Senior Secured Loans—First Lien Senior Secured Loans—Second Lien Senior Secured Bonds Asset Based Finance Preferred Equity Sustainable Infrastructure Investments, LLC Equity/Other Total Fair value at beginning of period $ 237,307 $ 54,424 $ 9,874 $ — $ 259,990 $ 39,427 $ 238,458 $ 839,480 Accretion of discount (amortization of premium) 363 13 14 — 100 — — 490 Net realized gain (loss) 942 — 2 — 1,016 — — 1,960 Net change in unrealized appreciation (depreciation) (18,394) 930 (66) — 70,846 1,403 (93,197) (38,478) Purchases 28,839 26,540 — 20,000 46 — 685 76,110 Paid-in-kind interest 291 1,029 — 329 — — — 1,649 Sales and repayments (28,252) (1,000) (53) — (7,267) — (695) (37,267) Transfers into Level 3 (1) — — — — — — 271 271 Transfers out of Level 3 — — — — — — — — Fair value at end of period $ 221,096 $ 81,936 $ 9,771 $ 20,329 $ 324,731 $ 40,830 $ 145,522 $ 844,215 The amount of total gains or losses for the period included in changes in net assets attributable to the change in unrealized gains or losses relating to investments still held at the reporting date $ (17,988) $ 930 $ (66) $ — $ 70,846 $ 1,403 $ (93,197) $ (38,072) For the Three Months Ended March 31, 2023 Senior Secured Loans—First Lien Senior Secured Loans—Second Lien Senior Secured Bonds Unsecured Debt Preferred Equity Sustainable Infrastructure Equity/Other Total Fair value at beginning of period $ 443,245 $ 143,270 $ 10,074 $ 54,374 $ 400,414 $ 51,098 $ 491,730 $ 1,594,205 Accretion of discount (amortization of premium) 349 81 12 29 579 — — 1,050 Net realized gain (loss) (2,806) 9 — 5 — — (15,008) (17,800) Net change in unrealized appreciation (depreciation) (5,939) 228 78 28 13,706 1,839 (47,355) (37,415) Purchases 24,949 — — — — — 83 25,032 Paid-in-kind interest 2,395 — — 2,107 — — — 4,502 Sales and repayments (8,110) (15,545) — (500) — — (37,826) (61,981) Transfers into Level 3 (1) — — — — — — 810 810 Transfers out of Level 3 — — — — — — — — Fair value at end of period $ 454,083 $ 128,043 $ 10,164 $ 56,043 $ 414,699 $ 52,937 $ 392,434 $ 1,508,403 The amount of total gains or losses for the period included in changes in net assets attributable to the change in unrealized gains or losses relating to investments still held at the reporting date $ (8,789) $ 228 $ 78 $ 28 $ 13,706 $ 1,839 $ (57,832) $ (50,742) ______________ (1) Changes in inputs or methodologies used for valuing investments may result in transfers into or out of levels within the fair value hierarchy. Transfers between levels of the fair value hierarchy are deemed to have occurred at the beginning of the reporting period. For the three months ended March 31, 2024 and 2023, transfers into Level 3 were due to decreased price transparency. The valuation techniques and significant unobservable inputs used in recurring Level 3 fair value measurements as of March 31, 2024 and December 31, 2023 were as follows: Type of Investment Fair Value at March 31, 2024 (Unaudited) Valuation Technique (1) Unobservable Input Range Weighted Senior Secured Loans—First Lien $ 168,409 Market Comparables Market Yield (%) 8.4%-20.5% 14.0% EBITDA Multiples (x) 2.5x-3.5x 3.0x 2,388 Discounted Cash Flow Discount Rate (%) 9.0%-11.0% 10.0% 50,299 Other (2) Senior Secured Loans—Second Lien 53,887 Market Comparables Market Yield (%) 12.0%-14.3% 13.0% 28,049 Other (2) Senior Secured Bonds 9,771 Market Comparables Market Yield (%) 7.5%-9.0% 8.3% Asset Based Finance 20,329 Income (3) Excess Spread (3) 1.6%-1.6% 1.6% Preferred Equity 319,022 Market Comparables Market Yield (%) 11.3%-18.5% 16.0% Net Aircraft Book Value Multiple (x) 1.0x-1.1x 1.0x 5,709 Other (2) Sustainable Infrastructure Investments, LLC 40,830 Discounted Cash Flow Discount Rate (%) 7.5%-10.0% 8.8% Equity/Other 44,650 Market Comparables EBITDA Multiples (x) 2.5x-9.3x 6.3x Production Multiples (MMcfe/d) $2,750.0-$3,350.0 $3,050.0 Proved Reserves Multiples (Bcfe) 0.7x-0.7x 0.7x PV-10 Multiples (x) 1.5x-1.7x 1.6x 80,339 Discounted Cash Flow Discount Rate (%) 8.0%-12.0% 10.0% 6,529 Option Valuation Model Volatility (%) 50.0%-60.0% 55.0% 14,004 Other (2) Total $ 844,215 Type of Investment Fair Value at Valuation Technique (1) Unobservable Input Range Weighted Senior Secured Loans—First Lien $ 212,250 Market Comparables Market Yield (%) 8.2%-20.5% 13.6% EBITDA Multiples (x) 3.9x-4.6x 4.4x 4,807 Discounted Cash Flow Discount Rate (%) 9.0%-13.0% 10.8% 20,250 Other (2) Senior Secured Loans—Second Lien 54,424 Market Comparables Market Yield (%) 12.5%-14.0% 13.1% Senior Secured Bonds 9,874 Market Comparables Market Yield (%) 7.5%-8.5% 8.0% Preferred Equity 259,990 Market Comparables Market Yield (%) 10.0%-23.0% 17.5% EBITDA Multiples (x) 12.0x-13.0x 12.5x Net Aircraft Book Value Multiple (x) 1.0x-1.1x 1.0x Sustainable Infrastructure Investments, LLC 39,427 Discounted Cash Flow Discount Rate (%) 8.0%-10.0% 9.0% Equity/Other 51,160 Market Comparables EBITDA Multiples (x) 2.7x-13.0x 6.0x Production Multiples (MMcfe/d) $3,000.0-$3,600.0 $3,300.0 Proved Reserves Multiples (Bcfe) 0.7x-0.7x 0.7x PV-10 Multiples (x) 0.3x-0.4x 0.3x 166,946 Discounted Cash Flow Discount Rate (%) 8.0%-17.1% 16.5% 7,121 Option Valuation Model Volatility (%) 55.0%-65.0% 60.0% 13,231 Other (2) Total $ 839,480 ______________ (1) For investments utilizing a market comparables valuation technique, a significant increase (decrease) in the market yield, in isolation, would result in a significantly lower (higher) fair value measurement, and a significant increase (decrease) in any of the valuation multiples, in isolation, would result in a significantly higher (lower) fair value measurement. For investments utilizing a discounted cash flow valuation technique, a significant increase (decrease) in the discount rate, in isolation, would result in a significantly lower (higher) fair value measurement. For investments utilizing an option valuation model valuation technique, a significant increase (decrease) in the volatility, in isolation, would result in a significantly higher (lower) fair value measurement. (2) Fair valued based on expected outcome of proposed corporate transactions, the expected value of the liquidation preference of the investment or other factors. (3) Fair value of the CLO Warehouse is based on cost plus the excess spread (accrued interest plus interest received less financing cost).

Financing Arrangement

Financing Arrangement	3 Months Ended
Financing Arrangement	Mar. 31, 2024
Debt Disclosure [Abstract]
Financing Arrangement	Financing Arrangement The following tables present a summary of information with respect to the Company’s outstanding financing arrangement as of March 31, 2024 and December 31, 2023. For additional information regarding the financing arrangement, see the notes to the Company’s audited consolidated financial statements contained in its annual report on Form 10-K for the year ended December 31, 2023. Any significant changes to the Company’s financing arrangement during the three months ended March 31, 2024 are discussed below. As of March 31, 2024 Arrangement (1) Type of Arrangement Rate (2) Amount Amount Maturity Date Barclays Facility Repurchase Term SOFR+3.00% $ 400,000 $ 100,000 September 6, 2026 As of December 31, 2023 Arrangement (1) Type of Arrangement Rate (2) Amount Amount Maturity Date Barclays Facility Repurchase Term SOFR+3.00% $ 400,000 $ 100,000 September 6, 2026 ______________________ (1) The carrying amount outstanding under the facility approximates its fair value, unless otherwise noted. (2) The financing fee under the Barclays Facility is based on three-month term SOFR (with a floor of 0.00%) plus a facility margin calculated monthly as the weighted average of the individual margin of the collateral obligations (subject to a floor, in the aggregate, of 3.00%). For the three months ended March 31, 2024 and 2023, the components of total interest expense for the Company's financing arrangements were as follows: Three Months Ended 2024 2023 Arrangement (1) Direct Interest Expense (2) Amortization of Deferred Financing Costs Total Interest Expense Direct Interest Expense (2) Amortization of Deferred Financing Costs and Discount Total Interest Expense Barclays Facility $ 8,568 $ 516 $ 9,084 $ — $ — $ — JPMorgan Facility (3) — — — 2,790 238 3,028 Senior Secured Notes (4) — — — 8,570 1,000 9,570 Total $ 8,568 $ 516 $ 9,084 $ 11,360 $ 1,238 $ 12,598 ___________________ (1) Borrowings of each of the Company's wholly-owned special-purpose financing subsidiaries are considered borrowings of the Company for purposes of complying with the asset coverage requirements applicable to BDCs under the 1940 Act. (2) Direct interest expense includes the effect of non-usage fees, administration fees and make-whole fees, if any. (3) On February 14, 2023, the Company repaid and terminated the JPMorgan Facility. (4) On May 15, 2023, the Company redeemed 100% of the issued and outstanding Senior Secured Notes at a price equal to 100% of the aggregate principal amount, plus the accrued but unpaid interest through to, but excluding, May 15, 2023. The Company’s average borrowings and weighted average interest rate, including the effect of non-usage fees, for the three months ended March 31, 2024, were $400,000 and 8.47%, respectively. As of March 31, 2024, the Company’s effective interest rate on borrowings, including the effect of non-usage fees, was 8.73%. The Company’s average borrowings and weighted average interest rate, including the effect of non-usage fees, for the three months ended March 31, 2023 were $606,516 and 8.31%, respectively. As of March 31, 2023, the Company’s effective interest rate on borrowings was 7.50%. Under its financing arrangements, the Company made certain representations and warranties and was required to comply with various covenants, reporting requirements and other customary requirements for similar financing arrangements. The Company was in compliance with all covenants required by its financing arrangements as of March 31, 2024 and December 31, 2023. Barclays Facility On September 6, 2023, the Company, through two wholly-owned, special purpose financing subsidiaries, FSSL Finance BB AssetCo LLC, or FSSL Finance BB AssetCo, and FSSL Finance BB Seller LLC, or FSSL Finance BB Seller, entered into a financing arrangement with Barclays Bank PLC, or Barclays, pursuant to which up to $500,000 will be made available to fund investments in loans and other corporate securities, or together, the Collateral Obligations, and for other general corporate purposes, or the Barclays Facility. The financing fee under the Barclays Facility is based on three-month term SOFR (with a floor of 0.00%) plus a facility margin calculated monthly as the weighted average of the individual margin of the Collateral Obligations (such individual margins ranging from 1.90% to 4.20%, depending on the type of Collateral Obligations; subject to a floor, in the aggregate, of 3.00%). Pursuant to the financing arrangement, the Company may contribute Collateral Obligations from time to time to FSSL Finance BB AssetCo, pursuant to a Sale and Contribution Agreement, dated as of September 6, 2023, between the Company and FSSL Finance BB AssetCo, or the Sale and Contribution Agreement. The assets held by FSSL Finance BB AssetCo secure the obligations of FSSL Finance BB AssetCo under the notes, or the Notes, issued by FSSL Finance BB AssetCo to FSSL Finance BB Seller, pursuant to an indenture, dated as of September 6, 2023, with Computershare Trust Company, N.A., or Computershare, as trustee, or the Indenture. Principal on the Notes will be due and payable on the stated maturity date of July 1, 2033, and the Notes do not bear interest. Pursuant to the Indenture, FSSL Finance BB AssetCo has made certain representations and warranties and is required to comply with various covenants, reporting requirements and other customary requirements for similar transactions. The Indenture contains events of default customary for similar transactions, including, without limitation: (a) failure to make principal payments on the Notes at their stated maturity or any earlier redemption date or to make interest payments on the Notes; (b) failure to disburse amounts in accordance with the priority of payments; (c) occurrence of certain bankruptcy and insolvency events with respect to FSSL Finance BB AssetCo; and (d) occurrence of a Repurchase Date under the Repurchase Agreement (defined below) as a result of an event of default with respect to FSSL Finance BB Seller. FSSL Finance BB Seller acquired and subscribed for the Notes pursuant to a Subscription Agreement, dated as of September 6, 2023, between FSSL Finance BB AssetCo and FSSL Finance BB Seller as the investor. On September 6, 2023, FSSL Finance BB Seller entered into a Master Confirmation in respect of Repurchase Transactions with Barclays, or the Confirmation, which supplements and is subject to the Master Repurchase Agreement, dated as of September 6, 2023, between FSSL Finance BB Seller and Barclays, or the Master Repurchase Agreement, and such Master Repurchase Agreement, as supplemented and evidenced by the Confirmation, or the Repurchase Agreement. Pursuant to the Repurchase Agreement, on one or more occasions beginning September 6, 2023, Barclays began purchasing the Notes held by FSSL Finance BB Seller for an aggregate purchase price of $400,000 outstanding as of March 31, 2024, which price may, subject to satisfaction of certain conditions, increase from time to time up to the maximum aggregate purchase price of $500,000. The scheduled Repurchase Date is September 6, 2026. Pursuant to the Repurchase Agreement, FSSL Finance BB Seller has made certain representations and warranties and is required to comply with various covenants, reporting requirements and other customary requirements for similar transactions. The Repurchase Agreement contains events of default customary for similar financing transactions, including, without limitation: (a) failure to pay the repurchase price upon the applicable payment dates; (b) failure to pay the financing fees and make-whole amounts when due; (c) failure to post collateral as required; (d) occurrence of an event of default under the Indenture, (e) occurrence of insolvency events with respect to FSSL Finance BB Seller; (f) cross default by the Company with respect to its indebtedness above a certain threshold amount and (g) financial covenant breach by the Company. As of March 31, 2024, Notes in an aggregate principal amount of $400,000 had been purchased by FSSL Finance BB Seller from FSSL Finance BB AssetCo and subsequently sold to Barclays under the Barclays Facility for aggregate proceeds of $394,953. The carrying amount outstanding under the Barclays Facility approximates its fair value. The Company funded the purchase of Notes by FSSL Finance BB Seller through a capital contribution to FSSL Finance BB Seller. The Notes issued by FSSL Finance BB AssetCo and purchased by FSSL Finance BB Seller eliminate in consolidation on the Company's financial statements. The Company incurred costs of $6,199 in connection with obtaining the Barclays Facility, which the Company has recorded as deferred financing costs on its consolidated balance sheet and amortizes to interest expense over the life of the Barclays Facility. As of March 31, 2024, $5,047 of such deferred financing costs had yet to be amortized to interest expense. JPMorgan Facility On August 16, 2018, the Company entered into that certain Senior Secured Credit Agreement, by and among the Company, the lenders party thereto, JPMorgan Chase Bank, N.A., or JPMorgan, as administrative agent and collateral agent, and the other parties signatory thereto, or as amended, the JPMorgan Facility. On February 14, 2023, the Company repaid and terminated the JPMorgan Facility. Prior to the termination of the JPMorgan Facility, $305,676 aggregate principal amount of loans were outstanding to the Company and such loans accrued interest at a rate equal to LIBOR (subject to a 0.00% floor) plus 3.00% per annum. The Company incurred certain customary costs and expenses in connection with the termination of the JPMorgan Facility. 7.500% Senior Secured Notes due 2023 On August 16, 2018, the Company, U.S. Bank National Association, or U.S Bank, as trustee, and certain subsidiaries of the Company, entered into an Indenture relating to the Company’s issuance of $500,000 aggregate principal amount of its 7.500% Senior Secured Notes due 2023, or the Senior Secured Notes. On May 15, 2023, the Company redeemed 100% of the issued and outstanding Senior Secured Notes at a price equal to 100% of the aggregate principal amount, plus the accrued but unpaid interest through to, but excluding, May 15, 2023. The Company incurred certain customary costs and expenses in connection with the redemption of the Senior Secured Notes.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
Commitments and Contingencies	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies The Company enters into contracts that contain a variety of indemnification provisions. The Company’s maximum exposure under these arrangements is unknown; however, the Company has not had prior claims or losses pursuant to these contracts. FS/EIG Advisor has reviewed the Company’s existing contracts and expects the risk of loss to the Company to be remote. The Company is not currently subject to any material legal proceedings and, to the Company’s knowledge, no material legal proceedings are threatened against the Company. From time to time, the Company may be a party to certain legal proceedings in the ordinary course of business, including proceedings relating to the enforcement of the Company’s rights under contracts with its portfolio companies. While the outcome of any legal proceedings cannot be predicted with certainty, the Company does not expect that any such proceedings will have a material effect upon its financial condition or results of operations. See Note 4 for a discussion of the Company’s commitments to FS/EIG Advisor and its affiliates (including FS Investments) and Note 7 for a discussion of the Company’s unfunded commitments.

Financial Highlights

Financial Highlights	3 Months Ended
Financial Highlights	Mar. 31, 2024
Investment Company [Abstract]
Financial Highlights	Financial Highlights The following is a schedule of financial highlights of the Company for the three months ended March 31, 2024 and the year ended December 31, 2023: Three Months Ended (Unaudited) Year Ended December 31, 2023 Per Share Data: (1) Net asset value, beginning of period $ 3.43 $ 3.88 Results of operations (2) Net investment income 0.10 0.18 Net realized gain (loss) and unrealized appreciation (depreciation) (0.06) (0.44) Net increase (decrease) in net assets resulting from operations 0.04 (0.26) Shareholder distributions (3) Distributions from net investment income (0.00) (0.19) Net decrease in net assets resulting from shareholder distributions (0.00) (0.19) Capital share transactions Issuance of common shares (4) — — Net increase (decrease) in net assets resulting from capital share transactions — — Net asset value, end of period $ 3.47 $ 3.43 Shares outstanding, end of period 455,506,155 455,506,155 Total return (5) 1.27 % (6.89) % Total return (without assuming reinvestment of distributions) (5) 1.17 % (6.70) % Ratio/Supplemental Data: Net assets, end of period $ 1,578,617 $ 1,562,055 Ratio of net investment income to average net assets (6)(7) 11.80 % 4.77 % Ratio of total operating expenses to average net assets (6) 5.80 % 4.50 % Ratio of management fee offset to average net assets (6) — (0.02) % Ratio of net operating expenses to average net assets (6) 5.80 % 4.48 % Ratio of interest expense to average net assets (6) 2.31 % 1.39 % Portfolio turnover (8) 7.94 % 45.84 % Total amount of senior securities outstanding, exclusive of treasury securities $ 400,000 $ 400,000 Asset coverage per unit (9) $ 4,947 $ 4,905 Asset coverage ratio (9) 4.95 4.91 _________________________ (1) Per share data may be rounded in order to recompute the ending net asset value per share. (2) The per share data was derived by using the weighted average shares outstanding during the applicable period. (3) The per share data for distributions reflects the actual amount of distributions paid per share during the applicable period. (4) The issuance of common shares on a per share basis reflects the incremental net asset value changes as a result of the issuance of common shares pursuant to the Company’s distribution reinvestment plan. The issuance of common shares at a price that is greater than the net asset value per share results in an increase in net asset value per share. (5) The total return for each period presented was calculated based on the change in net asset value during the applicable period, including the impact of distributions reinvested in accordance with the Company’s distribution reinvestment plan. Following the termination of the Company’s distribution reinvestment plan effective September 15, 2023, the total return for each period presented subsequent to the effective date was calculated based on the change in net asset value during the applicable period, assuming the reinvestment of all distributions at the Company’s net asset value per share as of the end of the applicable period. The total return (without assuming reinvestment of distributions) for each period presented was calculated by taking the net asset value per share as of the end of the applicable period, adding the cash distributions per share which were declared during the applicable period and dividing the total by the net asset value per share at the beginning of the applicable period. The total returns do not consider the effect of any sales commissions or charges that may be incurred in connection with the sale of the Company’s common shares. The total returns include the effect of the issuance of common shares at a net offering price that is greater than net asset value per share, which causes an increase in net asset value per share. The historical calculations of total returns in the table should not be considered representations of the Company’s future total returns, which may be greater or less than the returns shown in the table due to a number of factors, including the Company’s ability or inability to make investments in companies that meet its investment criteria, the interest rates payable on the debt securities the Company acquires, the level of the Company’s expenses, variations in and the timing of the recognition of realized and unrealized gains or losses, the degree to which the Company encounters competition in its markets and general economic conditions. As a result of these factors, results for any previous period should not be relied upon as being indicative of performance in future periods. The total return calculations set forth above represent the total returns on the Company’s investment portfolio during the applicable period and do not represent actual returns to shareholders. (6) Weighted average net assets during the applicable period are used for this calculation. Ratios for the three months ended March 31, 2024 are annualized. Annualized ratios for the three months ended March 31, 2024 are not necessarily indicative of the ratios that may be expected for the year ending December 31, 2024. (7) If FS/EIG Advisor had not agreed to offset the amount of any structuring, upfront or certain other fees it or its members received against the management fee payable by the Company, the ratio of net investment income to average net assets would have been 11.80% and 4.75% for the three months ended March 31, 2024 and the year ended December 31, 2023, respectively. See Note 4 for a discussion of the management fee offset with FS/EIG Advisor. (8) Portfolio turnover for the three months ended March 31, 2024 is not annualized. (9) Asset coverage per unit is the ratio of the carrying value of the Company’s total consolidated assets, less liabilities and indebtedness not represented by senior securities, to the aggregate amount of senior securities representing indebtedness. Asset coverage per unit is expressed in terms of dollar amounts per $1,000 of indebtedness.

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net increase (decrease) in net assets resulting from operations	$ 18,111	$ (32,554)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Mar. 31, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

N-2

N-2 - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
N-2 - USD ($) $ / shares in Units, $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Cover [Abstract]
Entity Central Index Key	0001501729
Amendment Flag	false
Securities Act File Number	814-00841
Document Type	10-Q
Entity Registrant Name	FS Specialty Lending Fund
Entity Address, Address Line One	201 Rouse Boulevard
Entity Address, City or Town	Philadelphia
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	19112
City Area Code	215
Local Phone Number	495-1150
Entity Emerging Growth Company	false
Financial Highlights [Abstract]
Senior Securities Amount	$ 400,000	$ 400,000
Senior Securities Coverage per Unit	$ 4,947	$ 4,905
General Description of Registrant [Abstract]
Investment Objectives and Practices [Text Block]	May 2023, we announced that our board of trustees approved our transition from an investment policy of investing primarily in Energy companies to a diversified credit investment policy of investing across private and public credit in a broader set of industries, sectors and sub-sectors. We commenced transitioning our portfolio holdings away from Energy investments in May 2023, while remaining in compliance with our then-current investment policy. Following a shareholder notice period, the new policy became effective on September 29, 2023. Our allocation to Energy investments is expected to decline over time through the natural course of maturities, repayments and sales activity and by growing the total size of the portfolio through leverage facilities. The pace of the portfolio rotation is dependent upon a number of factors, including the turnover of concentrated illiquid Energy investments, performance of underlying portfolio companies, high yield and energy market conditions, our access to borrowings and the amount and pace of the payment of enhanced distributions to shareholders, among others. Our current investment policy is to invest primarily in a portfolio of secured and unsecured floating and fixed rate loans, bonds and other types of credit instruments, which, under normal circumstances, will represent at least 80% of our total assets. This investment policy may not be changed without at least 60 days’ prior notice to holders of our common shares of any such change. Our current investment objectives are to generate current income and, to a lesser extent, long-term capital appreciation. We intend to pursue our investment objectives by investing in both direct originations and broadly syndicated investments of secured and unsecured floating and fixed rate loans, bonds and other types of credit instruments. Investing in both direct originations and broadly syndicated investments allows us to be dynamic in our pursuit of opportunities across changing economic and credit cycles. We intend to focus on the following investment categories in an effort to generate returns for our investors with an acceptable level of risk. • Direct Originations : Direct lending and innovative capital structure solutions to both sponsored and non-sponsored companies, typically based in the U.S. and operating within the middle market. These investments may include both debt and equity components. • Broadly Syndicated Loan and Bond Transactions : Opportunistic investments into primary and secondary markets, broadly syndicated loans and bonds. Broadly syndicated loans and bonds are generally more liquid than our directly originated investments and provide a complement to our less liquid strategies. In the case of broadly syndicated investments, we generally intend to capitalize on market inefficiencies by investing in loans, bonds, and other asset classes where the market price of such investment reflects a lower value than we believe is warranted based on our fundamental analysis, providing us with an opportunity to earn an attractive return on our investment. However, we may pursue other investment opportunities if we believe they are in our best interests and consistent with our investment objectives. Prior to September 29, 2023, our investment policy was to invest, under normal circumstances, at least 80% of our total assets in securities of Energy companies and our investment objectives were to generate current income and long-term capital appreciation. We pursued our previous investment objectives by focusing on the following seven investment themes: (i) basin-on-basin competition in U.S. shale, (ii) globalization of natural gas, (iii) coal retirements and the evolving energy generation mix, (iv) renewables focused on power grid parity, (v) export infrastructure for emerging U.S. producers, (vi) market liberalization opening new markets and (vii) midstream infrastructure connecting new supplies. However, we could pursue other investment opportunities if we believed they were in our best interests and consistent with our then-current investment objectives. The majority of our portfolio is comprised of income-oriented securities, which principally refers to debt securities and other income-producing investments, of privately-held companies within the United States. Historically, our portfolio has largely been invested in Energy companies, although we expect our portfolio to continue to shift away from investments in Energy companies as we pursue a diversified credit strategy. Generally, in the long-term we expect to weight our investments more heavily towards directly originated investments, as this will provide us with the ability to tailor investments to best match a project’s or company’s needs with our investment objectives. However, our current investment policy enables FS/EIG Advisor to opportunistically invest in broadly syndicated investments and dynamically adjust allocations between private and public markets depending on where the risk-adjusted returns are most attractive. We intend to weight our portfolio towards senior secured debt, which we believe offers opportunities for superior risk-adjusted returns and income generation. Our debt investments may take the form of corporate or project loans or bonds, may be secured or unsecured and may, in some cases, be accompanied by yield enhancements. These yield enhancements are typically expected to include warrants, options, net profits interests, cash flow participations or other forms of equity participation that can provide additional consideration or “upside” in a transaction. Our current preferred equity investments are generally directly originated and may take the form of perpetual or redeemable securities, typically with a current income component and minimum base returns. In addition, certain income-oriented preferred or common equity interests may include interests in master limited partnerships, or MLPs. MLPs are entities that (i) are structured as limited partnerships or limited liability companies, (ii) are publicly traded, (iii) satisfy certain requirements to be treated as partnerships for U.S. federal income tax purposes and (iv) primarily own and operate midstream and upstream Energy companies. A portion of our portfolio may be comprised of derivatives, including the use of total return swaps, credit default swaps and other swap contracts. In connection with certain of our debt investments or any restructuring of these debt investments, we may on occasion receive equity interests, including warrants or options, as additional consideration or otherwise in connection with a restructuring. FS/EIG Advisor will seek to tailor our investment focus as market conditions evolve. Our future financial condition, results of operations and cash flows may be impacted by the transition to a new investment policy.
NAV Per Share	$ 3.47	$ 3.43	$ 3.88

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
Summary of Significant Accounting Policies (Policies)	Mar. 31, 2024
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation: The accompanying unaudited consolidated financial statements of the Company have been prepared in accordance with accounting principles generally accepted in the United States of America, or GAAP, for interim financial information and with the instructions for Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included. For a more complete discussion of significant accounting policies and certain other information, the Company’s interim unaudited consolidated financial statements should be read in conjunction with its audited consolidated financial statements as of and for the year ended December 31, 2023 included in the Company’s annual report on Form 10-K. Operating results for the three months ended March 31, 2024 are not necessarily indicative of the results that may be expected for the year ending December 31, 2024. The December 31, 2023 consolidated balance sheet and consolidated schedule of investments are derived from the Company's audited consolidated financial statements as of and for the year ended December 31, 2023. The Company is considered an investment company under GAAP and follows the accounting and reporting guidance applicable to investment companies under Accounting Standards Codification Topic 946, Financial Services—Investment Companies. The Company has evaluated the impact of subsequent events through the date the unaudited consolidated financial statements were issued and filed with the Securities and Exchange Commission, or the SEC.
Use of Estimates	Use of Estimates: The preparation of the unaudited consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Many of the amounts have been rounded, and all amounts are in thousands, except share and per share amounts.
Capital Gains Incentive Fee and Subordinated Income Incentive Fee	Capital Gains Incentive Fee: Subordinated Income Incentive Fee:
Reclassifications	Reclassifications:
Revenue Recognition	Revenue Recognition: Security transactions are accounted for on the trade date. The Company records interest income on an accrual basis to the extent that it expects to collect such amounts. The Company records dividend income on the ex-dividend date. Distributions received from limited liability company, or LLC, and limited partnership, or LP, investments are evaluated to determine if the distribution should be recorded as dividend income or a return of capital. The Company does not accrue as a receivable interest or dividends on loans and securities if it has reason to doubt its ability to collect such income. The Company’s policy is to place investments on non-accrual status when there is reasonable doubt that interest income will be collected. The Company considers many factors relevant to an investment when placing it on or removing it from non-accrual status including, but not limited to, the delinquency status of the investment, economic and business conditions, the overall financial condition of the underlying investment, the value of the underlying collateral, bankruptcy status, if any, and any other facts or circumstances relevant to the investment. If there is reasonable doubt that the Company will receive any previously accrued interest, then the accrued interest will be written-off. Payments received on non-accrual investments may be recognized as income or applied to principal depending upon the collectability of the remaining principal and interest. Non-accrual investments may be restored to accrual status when principal and interest become current and are likely to remain current based on the Company’s judgment. Loan origination fees, original issue discount and market discount are capitalized and the Company amortizes such amounts as interest income over the respective term of the loan or security. Upon the prepayment of a loan or security, any unamortized loan origination fees and original issue discount are recorded as interest income. Structuring and other non-recurring upfront fees are recorded as fee income when earned. The Company records prepayment premiums on loans and securities as fee income when it earns
Derivative Instruments	Derivative Instruments: The Company’s derivative instruments may include fixed price swaps and equity total return swaps. The Company recognizes all derivative instruments as assets or liabilities at fair value in its consolidated financial statements. Derivative contracts entered into by the Company are not designated as hedging instruments for accounting purposes, and as a result, the Company presents changes in fair value through net change in unrealized appreciation (depreciation) on swap contracts in the consolidated statements of operations. Realized gains and losses of the derivative instruments are included in net realized gain (loss) on swap contracts in the consolidated statements of operations.
Collateralized Loan Obligation	Collateralized Loan Obligation – Warehouses: A Collateralized Loan Obligation Warehouse, or CLO Warehouse, is an entity organized for the purpose of holding syndicated bank loans, also known as leveraged loans, prior to the issuance of securities from that same vehicle. During the warehouse period, a CLO Warehouse will secure investments and build a portfolio of primarily leveraged loans and other debt obligations. The warehouse period terminates when the collateralized loan obligation vehicle issues various tranches of securities to the market. At this time, financing through the issuance of debt securities and subordinated notes is used to repay the bank financing. The fair value of the Company’s investment in the CLO Warehouse is determined by adding the excess spread (accrued interest plus interest received less financing cost) to the Company’s initial investment in the CLO Warehouse. Consistent with Accounting Standards Codification Topic 820, Fair Value Measurements and Disclosure
Recent Accounting Pronouncements	Recent Accounting Pronouncements: In June 2022, the FASB issued Accounting Standards Update No. 2022-03, Fair Value Measurement (Topic 820): Fair Value Measurement of Equity Securities Subject to Contractual Sale Restrictions , or ASU 2022-03, which clarifies guidance for fair value measurement of an equity security subject to a contractual sale restriction and establishes new disclosure requirements for such equity securities. ASU 2022-03 is effective for fiscal years beginning after December 15, 2023 and for interim periods within those fiscal years, with early adoption permitted. The Company has concluded that this guidance did not have a material impact on its consolidated financial statements.

Share Transactions (Tables)

Share Transactions (Tables)	3 Months Ended
Share Transactions (Tables)	Mar. 31, 2024
Equity [Abstract]
Schedule of Common Stock Transactions	Below is a summary of transactions with respect to the Company’s common shares during the three months ended March 31, 2024 and 2023: Three Months Ended 2024 2023 Shares Amount Shares Amount Reinvestment of Distributions (1) — $ — 1,321,335 $ 5,218 Proceeds from Share Transactions — $ — 1,321,335 $ 5,218 ______________ (1) On September 15, 2023, the Company's second amended and restated distribution reinvestment plan terminated.

Related Party Transactions (Tab

Related Party Transactions (Tables)	3 Months Ended
Related Party Transactions (Tables)	Mar. 31, 2024
Related Party Transactions [Abstract]
Schedule of the Fees and Expenses Accrued Under Investment Advisory Agreement	The following table describes the fees and expenses accrued under the FS/EIG investment advisory agreement during the three months ended March 31, 2024 and 2023: Three Months Ended Related Party Source Agreement Description 2024 2023 FS/EIG Advisor FS/EIG investment advisory agreement Base Management Fee (1) $ 9,112 $ 10,219 FS/EIG Advisor FS/EIG investment advisory agreement Administrative Services Expenses (2) $ 1,535 $ 1,320 _________________________ (1) During the three months ended March 31, 2024 and 2023, $8,416 and $11,185, respectively, in base management fees were paid to FS/EIG Advisor. The base management fee amount shown in the table above is shown net of $255 in structuring, upfront or certain other fees received by FS/EIG Advisor or its members and offset against base management fees for the three months ended March 31, 2023. There were no fees offset during the three months ended March 31, 2024. As of March 31, 2024 , $9,112 in base management fees were payable to FS/EIG Advisor. (2) During the three months ended March 31, 2024 and 2023, $733 and $645, respectively, of the accrued administrative services expenses related to the allocation of costs of administrative personnel for services rendered to the Company by FS/EIG Advisor and the remainder related to other reimbursable expenses. The Company paid $1,149 and $1,458 in administrative services expenses to FS/EIG Advisor, or its affiliates, during the three months ended March 31, 2024 and 2023, respectively.

Distributions (Tables)

Distributions (Tables)	3 Months Ended
Distributions (Tables)	Mar. 31, 2024
Income Tax Disclosure [Abstract]
Schedule of Cash Distributions Paid on Common Stock Including Tax Basis	The following table reflects the cash distributions per share that the Company declared on its common shares during the three months ended March 31, 2024 and 2023: Distribution For the Three Months Ended Per Share Amount Fiscal 2023 March 31, 2023 $ 0.0300 $ 13,584 Fiscal 2024 March 31, 2024 (1) $ 0.0034 $ 1,549 _________________________ (1) For the quarter ended December 31, 2023, the distribution amount per share was $0.0643, comprised of an initial distribution per share of $0.0609 declared in December 2023 and the remaining distribution per share of $0.0034 declared in January 2024, collectively representing an annualized distribution rate to shareholders of 7.5%. The following table reflects the sources of the cash distributions on a tax basis that the Company declared on its common shares during the three months ended March 31, 2024 and 2023: Three Months Ended 2024 2023 Source of Distribution Distribution Amount Percentage Distribution Amount Percentage Net investment income (1) $ 1,549 100 % $ 13,584 100 % Short-term capital gains proceeds from the sale of assets — — — — Long-term capital gains proceeds from the sale of assets — — — — Total $ 1,549 100 % $ 13,584 100 % _________________________ (1) During the three months ended March 31, 2024 and 2023, 94.5% and 86.6%, respectively, of the Company's gross investment income was attributable to cash income earned, 2.4% and 10.5%, respectively, was attributable to paid-in-kind, or PIK, interest and 3.1% and 2.9%, respectively, was attributable to non-cash accretion of discount.

Financial Instruments (Tables)

Financial Instruments (Tables)	3 Months Ended
Financial Instruments (Tables)	Mar. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Fixed Price Swap Positions	The following table presents the fair value of open swap contracts (which are not considered to be hedging instruments for accounting purposes) as of March 31, 2024 and December 31, 2023: March 31, 2024 December 31, 2023 Instrument Asset (1) Liability Asset Liability Nomura Total Return Swap $ — $ — $ — $ — BNP Paribas Total Return Swap 196 — — — Total $ 196 $ — $ — $ — ______________ (1) Reflected on the Company's consolidated balance sheets as: Unrealized appreciation on swap contracts.
Schedule of Realized and Unrealized Gain (Loss) on Derivative Instruments	The effect of swap contracts (which are not considered to be hedging instruments for accounting purposes) on the Company's statements of operations for the three months ended March 31, 2024 and 2023 were as follows: Net Realized Gains (Losses) (1) Net Change in Unrealized (2) Three Months Ended Three Months Ended Instrument 2024 2023 2024 2023 Commodity Fixed Price Swaps—Crude Oil $ — $ (100) $ — $ 733 Commodity Fixed Price Swaps—Natural Gas — 112 — 344 Nomura Total Return Swap 2,302 — — — BNP Paribas Total Return Swap 25 — 196 — Total $ 2,327 $ 12 $ 196 $ 1,077 ______________ (1) Reflected on the Company's consolidated statements of operations as: Net realized gain (loss) on swap contracts. (2) Reflected on the Company's consolidated statements of operations as: Net change in unrealized appreciation (depreciation) on swap contracts.
Schedule of Offsetting Liabilities	The following table presents the Company’s derivative assets and liabilities by counterparty, net of amounts available for offset under a master netting agreement and net of any collateral received or pledged by the Company for such assets and liabilities as of March 31, 2024: As of March 31, 2024 Counterparty Derivative Assets Derivative Liabilities Net Value of Derivatives Non-Cash Collateral (Received) Pledged (1) Cash Collateral (Received) Pledged (1) Net Amount of Derivative Assets (Liabilities) (2) BNP Paribas $ 196 — $ 196 — — $ 196 ______________ (1) In some instances, the actual amount of the collateral received and/or pledged may be more than the amount shown due to overcollateralization. (2) Net amount of derivative assets and liabilities represents the net amount due from the counterparty to the Company and the net amount due from the Company to the counterparty, respectively, in the event of default.
Schedule of Offsetting Assets	The following table presents the Company’s derivative assets and liabilities by counterparty, net of amounts available for offset under a master netting agreement and net of any collateral received or pledged by the Company for such assets and liabilities as of March 31, 2024: As of March 31, 2024 Counterparty Derivative Assets Derivative Liabilities Net Value of Derivatives Non-Cash Collateral (Received) Pledged (1) Cash Collateral (Received) Pledged (1) Net Amount of Derivative Assets (Liabilities) (2) BNP Paribas $ 196 — $ 196 — — $ 196 ______________ (1) In some instances, the actual amount of the collateral received and/or pledged may be more than the amount shown due to overcollateralization. (2) Net amount of derivative assets and liabilities represents the net amount due from the counterparty to the Company and the net amount due from the Company to the counterparty, respectively, in the event of default.

Investment Portfolio (Tables)

Investment Portfolio (Tables)	3 Months Ended
Investment Portfolio (Tables)	Mar. 31, 2024
Schedule of Investments [Abstract]
Schedule of Investments	The following table summarizes the composition of the Company’s investment portfolio at cost and fair value as of March 31, 2024 and December 31, 2023: March 31, 2024 December 31, 2023 Amortized Cost (1) Fair Value Percentage Amortized Cost (1) Fair Value Percentage Senior Secured Loans—First Lien $ 1,031,295 $ 962,663 53 % $ 878,013 $ 825,158 54 % Senior Secured Loans—Second Lien 81,646 81,936 5 % 55,064 54,424 4 % Senior Secured Bonds 96,035 98,436 6 % 82,793 84,468 5 % Asset Based Finance 20,329 20,329 1 % — — — Preferred Equity 246,345 324,731 18 % 252,450 259,990 17 % Sustainable Infrastructure Investments, LLC 43,150 40,830 2 % 43,150 39,427 3 % Equity/Other 211,451 145,522 8 % 211,461 238,729 16 % Short-Term Investments 126,763 126,825 7 % 20,994 21,000 1 % Total $ 1,857,014 $ 1,801,272 100 % $ 1,543,925 $ 1,523,196 100 % ______________ (1) Amortized cost represents the original cost adjusted for the amortization of premiums and/or accretion of discounts, as applicable, on investments. The table below describes investments by industry classification and enumerates the percentage, by fair value, of the total portfolio assets in such industries as of March 31, 2024 and December 31, 2023: March 31, 2024 December 31, 2023 Industry Classification Fair Value Percentage Fair Value Percentage Energy—Midstream $ 354,759 20 % $ 303,175 20 % Energy—Upstream 214,120 12 % 309,456 20 % Consumer Services 190,829 11 % 156,089 10 % Capital Goods 140,295 8 % 116,454 8 % U.S. Treasury 126,825 7 % 21,000 1 % Commercial & Professional Services (1) 100,700 6 % 62,036 4 % Financial Services 90,663 5 % 83,197 6 % Health Care Equipment & Services 90,338 5 % 73,105 5 % Consumer Discretionary Distribution & Retail 67,022 4 % 37,428 3 % Energy—Power 58,581 3 % 69,696 5 % Materials 55,906 3 % 49,653 3 % Automobiles & Components 49,639 3 % 39,521 3 % Transportation 42,092 2 % 30,157 2 % Household & Personal Products 26,081 1 % 20,858 1 % Insurance 25,269 1 % 20,251 1 % Consumer Durables & Apparel 24,404 1 % — — Consumer Staples Distribution & Retail 24,337 1 % 18,830 1 % Telecommunication Services 19,400 1 % — — Pharmaceuticals, Biotechnology & Life Sciences 19,352 1 % 19,300 1 % Technology Hardware & Equipment 13,685 1 % — — Energy—Service & Equipment (1) 13,629 1 % 33,734 2 % Media & Entertainment 12,516 1 % 19,829 1 % Sustainable Infrastructure Investments, LLC (2) 40,830 2 % 39,427 3 % Total $ 1,801,272 100 % $ 1,523,196 100 % _____________________ (1) FS/EIG Advisor monitors the industry classification of the Company’s investments and may from time to time reclassify such investments if it determines such reclassification is appropriate. During the year ended December 31, 2023, two investments had their industry re-classified from Energy—Industrials to Commercial & Professional Services, and one investment had its industry re-classified from Energy—Service & Equipment to Commercial & Professional Services. (2) Sustainable Infrastructure Investments, LLC is generally comprised of midstream and renewables assets in the Energy sector.
Schedule of Nonconsolidated Subsidiary Portfolio	Below is a summary of SIIJV's portfolio, followed by a listing of the individual loans in SIIJV's portfolio as of March 31, 2024 and December 31, 2023: March 31, 2024 December 31, 2023 Total investments (1) $ 153,837 $ 170,083 Weighted average current interest rate on debt investments (2) 7.41 % 7.45 % Number of portfolio assets in SIIJV 5 6 Largest investment in a single portfolio company (1) $ 57,227 $ 57,227 _____________________ (1) At cost. (2) Computed as the (a) annual stated interest rate on accruing debt, divided by (b) total debt at par amount. Sustainable Infrastructure Investments, LLC Portfolio As of March 31, 2024 (Unaudited) Portfolio Company (a)(b) Energy Industry Rate (c) Maturity Principal Amortized Fair (d) Senior Secured Loans—First Lien—100.0% Blue Heron Intermediate Holdco I, LLC Midstream S+188 4/22/24 $ 30,343 $ 30,343 $ 30,389 Copper Mountain Solar 3, LLC Renewables S+188 5/31/25 16,104 16,104 16,217 FLNG Liquefaction 2, LLC Midstream S+150 12/31/26 26,164 26,164 26,335 NES Hercules Class B Member, LLC Renewables S+163 1/31/28 23,999 23,999 24,473 ST EIP Holdco LLC Midstream S+250 11/5/24 57,227 57,227 57,226 Total Senior Secured Loans—First Lien 153,837 154,640 TOTAL INVESTMENTS—100.0% $ 153,837 $ 154,640 Sustainable Infrastructure Investments, LLC Portfolio As of December 31, 2023 Portfolio Company (a)(b) Energy Industry Rate (c) Maturity Principal Amortized Fair (d) Senior Secured Loans—First Lien—100.0% Blue Heron Intermediate Holdco I, LLC Midstream S+188 4/22/24 $ 30,661 $ 30,661 $ 30,692 Copper Mountain Solar 3, LLC Renewables S+188 5/31/25 16,104 16,104 16,172 FLNG Liquefaction 2, LLC Midstream S+150 12/31/26 26,567 26,567 26,557 NES Hercules Class B Member, LLC Renewables S+163 1/31/28 24,176 24,176 24,769 ST EIP Holdco LLC Midstream S+250 11/5/24 57,227 57,227 57,143 Top of the World Wind Energy LLC Renewables S+213 12/1/28 15,348 15,348 15,616 Total Senior Secured Loans—First Lien 170,083 170,949 TOTAL INVESTMENTS—100.0% $ 170,083 $ 170,949 _____________________ Percentages are shown as a percentage of total investments. (a) Security may be an obligation of one or more entities affiliated with the named company. (b) Security or portion thereof is held within Seine Funding and is pledged as collateral supporting the amounts outstanding under the Seine Funding Facility. (c) Certain variable rate securities in SIIJV's portfolio bear interest at a rate determined by a publicly disclosed base rate plus a basis point spread. As of March 31, 2024 and December 31, 2023, the three-month SOFR, or S, was 5.30% and 5.33%, respectively. SOFR based contracts may include a credit spread adjustment that is charged in addition to the base rate and basis point spread. (d) Security is classified as Level 3 and fair value is determined in accordance with SIIJV’s valuation process. Below is selected balance sheet information for SIIJV as of March 31, 2024 and December 31, 2023: March 31, 2024 December 31, 2023 Selected Balance Sheet Information Total investments, at fair value $ 154,640 $ 170,949 Cash and other assets 20,017 29,089 Total assets $ 174,657 $ 200,038 Debt $ 121,041 $ 145,483 Other liabilities 1,900 3,406 Total liabilities 122,941 148,889 Members' equity $ 51,716 $ 51,149 Below is selected statement of operations information for SIIJV for the three months ended March 31, 2024 and 2023: Three Months Ended 2024 2023 Selected Statement of Operations Information Total investment income $ 3,210 $ 4,798 Expenses Interest expense 2,090 3,141 Administrative services 32 43 Custodian and accounting fees 46 45 Professional services 38 50 Other 10 10 Total expenses 2,216 3,289 Net investment income 994 1,509 Net realized and unrealized gain (loss) (427) 1,946 Net increase (decrease) in net assets resulting from operations $ 567 $ 3,455

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	3 Months Ended
Fair Value of Financial Instruments (Tables)	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Schedule of Fair Value Hierarchy of Investments	As of March 31, 2024 and December 31, 2023, the Company’s investments were categorized as follows in the fair value hierarchy: Valuation Inputs March 31, 2024 December 31, 2023 Level 1—Price quotations in active markets $ — $ — Level 2—Significant other observable inputs 957,057 683,716 Level 3—Significant unobservable inputs 844,215 839,480 Total $ 1,801,272 $ 1,523,196
Schedule of Fair Value Hierarchy of Assets and Liabilities	As of March 31, 2024 and December 31, 2023, the Company’s swap contracts were categorized as follows in the fair value hierarchy: March 31, 2024 December 31, 2023 Valuation Inputs Assets Liabilities Assets Liabilities Level 1—Price quotations in active markets $ — $ — $ — $ — Level 2—Significant other observable inputs 196 — — — Level 3—Significant unobservable inputs — — — — Total $ 196 $ — $ — $ —
Schedule of Fair Value of Assets Rollforward	The following is a reconciliation for the three months ended March 31, 2024 and 2023 of investments for which significant unobservable inputs (Level 3) were used in determining fair value: For the Three Months Ended March 31, 2024 Senior Secured Loans—First Lien Senior Secured Loans—Second Lien Senior Secured Bonds Asset Based Finance Preferred Equity Sustainable Infrastructure Investments, LLC Equity/Other Total Fair value at beginning of period $ 237,307 $ 54,424 $ 9,874 $ — $ 259,990 $ 39,427 $ 238,458 $ 839,480 Accretion of discount (amortization of premium) 363 13 14 — 100 — — 490 Net realized gain (loss) 942 — 2 — 1,016 — — 1,960 Net change in unrealized appreciation (depreciation) (18,394) 930 (66) — 70,846 1,403 (93,197) (38,478) Purchases 28,839 26,540 — 20,000 46 — 685 76,110 Paid-in-kind interest 291 1,029 — 329 — — — 1,649 Sales and repayments (28,252) (1,000) (53) — (7,267) — (695) (37,267) Transfers into Level 3 (1) — — — — — — 271 271 Transfers out of Level 3 — — — — — — — — Fair value at end of period $ 221,096 $ 81,936 $ 9,771 $ 20,329 $ 324,731 $ 40,830 $ 145,522 $ 844,215 The amount of total gains or losses for the period included in changes in net assets attributable to the change in unrealized gains or losses relating to investments still held at the reporting date $ (17,988) $ 930 $ (66) $ — $ 70,846 $ 1,403 $ (93,197) $ (38,072) For the Three Months Ended March 31, 2023 Senior Secured Loans—First Lien Senior Secured Loans—Second Lien Senior Secured Bonds Unsecured Debt Preferred Equity Sustainable Infrastructure Equity/Other Total Fair value at beginning of period $ 443,245 $ 143,270 $ 10,074 $ 54,374 $ 400,414 $ 51,098 $ 491,730 $ 1,594,205 Accretion of discount (amortization of premium) 349 81 12 29 579 — — 1,050 Net realized gain (loss) (2,806) 9 — 5 — — (15,008) (17,800) Net change in unrealized appreciation (depreciation) (5,939) 228 78 28 13,706 1,839 (47,355) (37,415) Purchases 24,949 — — — — — 83 25,032 Paid-in-kind interest 2,395 — — 2,107 — — — 4,502 Sales and repayments (8,110) (15,545) — (500) — — (37,826) (61,981) Transfers into Level 3 (1) — — — — — — 810 810 Transfers out of Level 3 — — — — — — — — Fair value at end of period $ 454,083 $ 128,043 $ 10,164 $ 56,043 $ 414,699 $ 52,937 $ 392,434 $ 1,508,403 The amount of total gains or losses for the period included in changes in net assets attributable to the change in unrealized gains or losses relating to investments still held at the reporting date $ (8,789) $ 228 $ 78 $ 28 $ 13,706 $ 1,839 $ (57,832) $ (50,742) ______________ (1) Changes in inputs or methodologies used for valuing investments may result in transfers into or out of levels within the fair value hierarchy. Transfers between levels of the fair value hierarchy are deemed to have occurred at the beginning of the reporting period. For the three months ended March 31, 2024 and 2023, transfers into Level 3 were due to decreased price transparency.
Schedule of Valuation Techniques and Significant Unobservable Inputs Used in Recurring Level 3 Fair Value	The valuation techniques and significant unobservable inputs used in recurring Level 3 fair value measurements as of March 31, 2024 and December 31, 2023 were as follows: Type of Investment Fair Value at March 31, 2024 (Unaudited) Valuation Technique (1) Unobservable Input Range Weighted Senior Secured Loans—First Lien $ 168,409 Market Comparables Market Yield (%) 8.4%-20.5% 14.0% EBITDA Multiples (x) 2.5x-3.5x 3.0x 2,388 Discounted Cash Flow Discount Rate (%) 9.0%-11.0% 10.0% 50,299 Other (2) Senior Secured Loans—Second Lien 53,887 Market Comparables Market Yield (%) 12.0%-14.3% 13.0% 28,049 Other (2) Senior Secured Bonds 9,771 Market Comparables Market Yield (%) 7.5%-9.0% 8.3% Asset Based Finance 20,329 Income (3) Excess Spread (3) 1.6%-1.6% 1.6% Preferred Equity 319,022 Market Comparables Market Yield (%) 11.3%-18.5% 16.0% Net Aircraft Book Value Multiple (x) 1.0x-1.1x 1.0x 5,709 Other (2) Sustainable Infrastructure Investments, LLC 40,830 Discounted Cash Flow Discount Rate (%) 7.5%-10.0% 8.8% Equity/Other 44,650 Market Comparables EBITDA Multiples (x) 2.5x-9.3x 6.3x Production Multiples (MMcfe/d) $2,750.0-$3,350.0 $3,050.0 Proved Reserves Multiples (Bcfe) 0.7x-0.7x 0.7x PV-10 Multiples (x) 1.5x-1.7x 1.6x 80,339 Discounted Cash Flow Discount Rate (%) 8.0%-12.0% 10.0% 6,529 Option Valuation Model Volatility (%) 50.0%-60.0% 55.0% 14,004 Other (2) Total $ 844,215 Type of Investment Fair Value at Valuation Technique (1) Unobservable Input Range Weighted Senior Secured Loans—First Lien $ 212,250 Market Comparables Market Yield (%) 8.2%-20.5% 13.6% EBITDA Multiples (x) 3.9x-4.6x 4.4x 4,807 Discounted Cash Flow Discount Rate (%) 9.0%-13.0% 10.8% 20,250 Other (2) Senior Secured Loans—Second Lien 54,424 Market Comparables Market Yield (%) 12.5%-14.0% 13.1% Senior Secured Bonds 9,874 Market Comparables Market Yield (%) 7.5%-8.5% 8.0% Preferred Equity 259,990 Market Comparables Market Yield (%) 10.0%-23.0% 17.5% EBITDA Multiples (x) 12.0x-13.0x 12.5x Net Aircraft Book Value Multiple (x) 1.0x-1.1x 1.0x Sustainable Infrastructure Investments, LLC 39,427 Discounted Cash Flow Discount Rate (%) 8.0%-10.0% 9.0% Equity/Other 51,160 Market Comparables EBITDA Multiples (x) 2.7x-13.0x 6.0x Production Multiples (MMcfe/d) $3,000.0-$3,600.0 $3,300.0 Proved Reserves Multiples (Bcfe) 0.7x-0.7x 0.7x PV-10 Multiples (x) 0.3x-0.4x 0.3x 166,946 Discounted Cash Flow Discount Rate (%) 8.0%-17.1% 16.5% 7,121 Option Valuation Model Volatility (%) 55.0%-65.0% 60.0% 13,231 Other (2) Total $ 839,480 ______________ (1) For investments utilizing a market comparables valuation technique, a significant increase (decrease) in the market yield, in isolation, would result in a significantly lower (higher) fair value measurement, and a significant increase (decrease) in any of the valuation multiples, in isolation, would result in a significantly higher (lower) fair value measurement. For investments utilizing a discounted cash flow valuation technique, a significant increase (decrease) in the discount rate, in isolation, would result in a significantly lower (higher) fair value measurement. For investments utilizing an option valuation model valuation technique, a significant increase (decrease) in the volatility, in isolation, would result in a significantly higher (lower) fair value measurement. (2) Fair valued based on expected outcome of proposed corporate transactions, the expected value of the liquidation preference of the investment or other factors. (3) Fair value of the CLO Warehouse is based on cost plus the excess spread (accrued interest plus interest received less financing cost).

Financing Arrangement (Tables)

Financing Arrangement (Tables)	3 Months Ended
Financing Arrangement (Tables)	Mar. 31, 2024
Debt Disclosure [Abstract]
Schedule of Outstanding Financing Arrangements	The following tables present a summary of information with respect to the Company’s outstanding financing arrangement as of March 31, 2024 and December 31, 2023. For additional information regarding the financing arrangement, see the notes to the Company’s audited consolidated financial statements contained in its annual report on Form 10-K for the year ended December 31, 2023. Any significant changes to the Company’s financing arrangement during the three months ended March 31, 2024 are discussed below. As of March 31, 2024 Arrangement (1) Type of Arrangement Rate (2) Amount Amount Maturity Date Barclays Facility Repurchase Term SOFR+3.00% $ 400,000 $ 100,000 September 6, 2026 As of December 31, 2023 Arrangement (1) Type of Arrangement Rate (2) Amount Amount Maturity Date Barclays Facility Repurchase Term SOFR+3.00% $ 400,000 $ 100,000 September 6, 2026 ______________________ (1) The carrying amount outstanding under the facility approximates its fair value, unless otherwise noted. (2) The financing fee under the Barclays Facility is based on three-month term SOFR (with a floor of 0.00%) plus a facility margin calculated monthly as the weighted average of the individual margin of the collateral obligations (subject to a floor, in the aggregate, of 3.00%).
Schedule of Interest Expense	For the three months ended March 31, 2024 and 2023, the components of total interest expense for the Company's financing arrangements were as follows: Three Months Ended 2024 2023 Arrangement (1) Direct Interest Expense (2) Amortization of Deferred Financing Costs Total Interest Expense Direct Interest Expense (2) Amortization of Deferred Financing Costs and Discount Total Interest Expense Barclays Facility $ 8,568 $ 516 $ 9,084 $ — $ — $ — JPMorgan Facility (3) — — — 2,790 238 3,028 Senior Secured Notes (4) — — — 8,570 1,000 9,570 Total $ 8,568 $ 516 $ 9,084 $ 11,360 $ 1,238 $ 12,598 ___________________ (1) Borrowings of each of the Company's wholly-owned special-purpose financing subsidiaries are considered borrowings of the Company for purposes of complying with the asset coverage requirements applicable to BDCs under the 1940 Act. (2) Direct interest expense includes the effect of non-usage fees, administration fees and make-whole fees, if any. (3) On February 14, 2023, the Company repaid and terminated the JPMorgan Facility. (4) On May 15, 2023, the Company redeemed 100% of the issued and outstanding Senior Secured Notes at a price equal to 100% of the aggregate principal amount, plus the accrued but unpaid interest through to, but excluding, May 15, 2023.

Financial Highlights (Tables)

Financial Highlights (Tables)	3 Months Ended
Financial Highlights (Tables)	Mar. 31, 2024
Investment Company [Abstract]
Schedule of Financial Highlights	The following is a schedule of financial highlights of the Company for the three months ended March 31, 2024 and the year ended December 31, 2023: Three Months Ended (Unaudited) Year Ended December 31, 2023 Per Share Data: (1) Net asset value, beginning of period $ 3.43 $ 3.88 Results of operations (2) Net investment income 0.10 0.18 Net realized gain (loss) and unrealized appreciation (depreciation) (0.06) (0.44) Net increase (decrease) in net assets resulting from operations 0.04 (0.26) Shareholder distributions (3) Distributions from net investment income (0.00) (0.19) Net decrease in net assets resulting from shareholder distributions (0.00) (0.19) Capital share transactions Issuance of common shares (4) — — Net increase (decrease) in net assets resulting from capital share transactions — — Net asset value, end of period $ 3.47 $ 3.43 Shares outstanding, end of period 455,506,155 455,506,155 Total return (5) 1.27 % (6.89) % Total return (without assuming reinvestment of distributions) (5) 1.17 % (6.70) % Ratio/Supplemental Data: Net assets, end of period $ 1,578,617 $ 1,562,055 Ratio of net investment income to average net assets (6)(7) 11.80 % 4.77 % Ratio of total operating expenses to average net assets (6) 5.80 % 4.50 % Ratio of management fee offset to average net assets (6) — (0.02) % Ratio of net operating expenses to average net assets (6) 5.80 % 4.48 % Ratio of interest expense to average net assets (6) 2.31 % 1.39 % Portfolio turnover (8) 7.94 % 45.84 % Total amount of senior securities outstanding, exclusive of treasury securities $ 400,000 $ 400,000 Asset coverage per unit (9) $ 4,947 $ 4,905 Asset coverage ratio (9) 4.95 4.91 _________________________ (1) Per share data may be rounded in order to recompute the ending net asset value per share. (2) The per share data was derived by using the weighted average shares outstanding during the applicable period. (3) The per share data for distributions reflects the actual amount of distributions paid per share during the applicable period. (4) The issuance of common shares on a per share basis reflects the incremental net asset value changes as a result of the issuance of common shares pursuant to the Company’s distribution reinvestment plan. The issuance of common shares at a price that is greater than the net asset value per share results in an increase in net asset value per share. (5) The total return for each period presented was calculated based on the change in net asset value during the applicable period, including the impact of distributions reinvested in accordance with the Company’s distribution reinvestment plan. Following the termination of the Company’s distribution reinvestment plan effective September 15, 2023, the total return for each period presented subsequent to the effective date was calculated based on the change in net asset value during the applicable period, assuming the reinvestment of all distributions at the Company’s net asset value per share as of the end of the applicable period. The total return (without assuming reinvestment of distributions) for each period presented was calculated by taking the net asset value per share as of the end of the applicable period, adding the cash distributions per share which were declared during the applicable period and dividing the total by the net asset value per share at the beginning of the applicable period. The total returns do not consider the effect of any sales commissions or charges that may be incurred in connection with the sale of the Company’s common shares. The total returns include the effect of the issuance of common shares at a net offering price that is greater than net asset value per share, which causes an increase in net asset value per share. The historical calculations of total returns in the table should not be considered representations of the Company’s future total returns, which may be greater or less than the returns shown in the table due to a number of factors, including the Company’s ability or inability to make investments in companies that meet its investment criteria, the interest rates payable on the debt securities the Company acquires, the level of the Company’s expenses, variations in and the timing of the recognition of realized and unrealized gains or losses, the degree to which the Company encounters competition in its markets and general economic conditions. As a result of these factors, results for any previous period should not be relied upon as being indicative of performance in future periods. The total return calculations set forth above represent the total returns on the Company’s investment portfolio during the applicable period and do not represent actual returns to shareholders. (6) Weighted average net assets during the applicable period are used for this calculation. Ratios for the three months ended March 31, 2024 are annualized. Annualized ratios for the three months ended March 31, 2024 are not necessarily indicative of the ratios that may be expected for the year ending December 31, 2024. (7) If FS/EIG Advisor had not agreed to offset the amount of any structuring, upfront or certain other fees it or its members received against the management fee payable by the Company, the ratio of net investment income to average net assets would have been 11.80% and 4.75% for the three months ended March 31, 2024 and the year ended December 31, 2023, respectively. See Note 4 for a discussion of the management fee offset with FS/EIG Advisor. (8) Portfolio turnover for the three months ended March 31, 2024 is not annualized. (9) Asset coverage per unit is the ratio of the carrying value of the Company’s total consolidated assets, less liabilities and indebtedness not represented by senior securities, to the aggregate amount of senior securities representing indebtedness. Asset coverage per unit is expressed in terms of dollar amounts per $1,000 of indebtedness.

Principal Business and Organi_2

Principal Business and Organization (Details)	Sep. 29, 2023	Sep. 28, 2023
Debt and Other Credit Investments
Schedule of Investments [Line Items]
Percentage of investments total assets	80%
Energy Investment
Schedule of Investments [Line Items]
Percentage of investments total assets		80%

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Related Party Transaction [Line Items]
Fee income	$ 0	$ 0
Investment Advisory Agreement - Incentive Rate, Realized Capital Gains \| Related Party
Related Party Transaction [Line Items]
Incentive fee (in percent)	20%
Investment Advisory Agreement - Incentive Rate, Quarterly In Arrears Catch-up Threshold \| Related Party
Related Party Transaction [Line Items]
Incentive fee (in percent)	20%
Investment Advisory Agreement - Incentive Rate, Quarterly Catch-up Threshold \| Related Party
Related Party Transaction [Line Items]
Incentive fee (in percent)	1.625%
Investment Advisory Agreement - Incentive Rate, Annualized Hurdle Rate \| Related Party
Related Party Transaction [Line Items]
Incentive fee (in percent)	6.50%
Investment Advisory Agreement - Incentive Rate, Pre-Incentive Fee Net Investment Income Below Catch-Up Threshold \| Related Party
Related Party Transaction [Line Items]
Incentive fee (in percent)	2.031%
Investment Advisory Agreement - Incentive Rate, Annualized Catch-Up Threshold \| Related Party
Related Party Transaction [Line Items]
Incentive fee (in percent)	8.125%

Share Transactions - Schedule o

Share Transactions - Schedule of Common Stock Transactions (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
Equity [Abstract]
Reinvestment of Distributions (in shares)		0	1,321,335
Reinvestment of Distributions	[1]	$ 0	$ 5,218
Proceeds from Share Transactions (in shares)		0	1,321,335
Proceeds from Share Transactions		$ 0	$ 5,218

[1] See Note 3 for a discussion of the Company's common share transactions.

Share Transactions - Narrative

Share Transactions - Narrative (Details) - Distribution Reinvestment Plan - USD ($) $ in Thousands		3 Months Ended
	May 05, 2017	Mar. 31, 2024	Mar. 31, 2023
Class of Stock [Line Items]
Distribution reinvestment plan term	12 months
Distribution reinvestment plan term expiree	3 months
Weighted average number of common shares outstanding in prior year	10%
Weighted average number of common shares outstanding	2.50%
Share distribution not more than net asset value per common share		2.50%
Termination period		30 days
Number of treasury shares repurchased (in shares)		0	0
Minimum investment threshold		$ 5
Written notice period		30 days

Related Party Transactions - Na

Related Party Transactions - Narrative (Details) - USD ($)			2 Months Ended	3 Months Ended
Related Party Transactions - Narrative (Details) - USD ($)		Apr. 18, 2024	Mar. 31, 2024	Mar. 31, 2024	Mar. 31, 2023	Apr. 26, 2024
Related Party Transaction [Line Items]
Investment company, contractual fee waived	[1]			$ 0	$ 255,000
Related Party \| Bridge Street Warehouse CLO IV Ltd.
Related Party Transaction [Line Items]
Unfunded commitments			$ 20,000,000	20,000,000
Interest income				$ 329,000
Related Party \| Bridge Street Warehouse CLO IV Ltd. \| Subsequent Event
Related Party Transaction [Line Items]
Principal amount						$ 354,700,000
Related Party \| Bridge Street Warehouse CLO IV Ltd. \| Subsequent Event \| Subordinated Debt
Related Party Transaction [Line Items]
Principal amount						$ 23,700,000
Related Party \| Bridge Street Warehouse CLO IV Ltd. \| Reported Value Measurement
Related Party Transaction [Line Items]
Aggregate sustainable infrastructure investments			20,000,000
Related Party \| Bridge Street Warehouse CLO IV Ltd. \| Reported Value Measurement \| Subsequent Event
Related Party Transaction [Line Items]
Aggregate sustainable infrastructure investments		$ 2,000,000
Related Party \| Bridge Street Warehouse CLO IV Ltd. \| Estimate of Fair Value Measurement
Related Party Transaction [Line Items]
Aggregate sustainable infrastructure investments			$ 20,329,000
Investment Advisory Agreement \| Related Party
Related Party Transaction [Line Items]
Management and service fees, base rate				1.75%
Investment company, contractual fee waived				$ 0	$ 255,000

[1]See Note 4 for a discussion of the offset by FS/EIG Advisor, LLC, the Company's investment adviser, of certain management fees to which it was otherwise entitled during the applicable period.

Related Party Transactions - Sc

Related Party Transactions - Schedule of the Fees and Expenses Accrued (Details) - USD ($)		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Related Party Transaction [Line Items]
Administrative services expenses		$ 1,535,000	$ 1,320,000
Management fees		9,112,000	10,474,000
Investment company, contractual fee waived	[1]	0	255,000
Management fees payable		9,112,000		$ 8,416,000
Related Party \| Investment Advisory Agreement
Related Party Transaction [Line Items]
Base management fee		9,112,000	10,219,000
Administrative services expenses		1,535,000	1,320,000
Management fees		8,416,000	11,185,000
Investment company, contractual fee waived		0	255,000
Management fees payable		9,112,000
Accounting and administrative fees		733,000	645,000
Payment for administrative services expenses		$ 1,149,000	$ 1,458,000

[1]See Note 4 for a discussion of the offset by FS/EIG Advisor, LLC, the Company's investment adviser, of certain management fees to which it was otherwise entitled during the applicable period.

Distributions - Cash Distributi

Distributions - Cash Distributions (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended		3 Months Ended			12 Months Ended
		Jan. 31, 2024	Dec. 31, 2023	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Distributions (in USD per share)				$ 0.0034		$ 0.0300	$ 0.19
Amount	[1]			$ 1,549		$ 13,584
Distribution to shareholders (in dollars per share)		$ 0.0034	$ 0.0609		$ 0.0643
Annualized distribution rate (percent)					7.50%

[1] See Note 5 for a discussion of the sources of distributions paid by the Company.

Distributions - Narrative (Deta

Distributions - Narrative (Details) - USD ($)		1 Months Ended		3 Months Ended		12 Months Ended
Distributions - Narrative (Details) - USD ($)	Apr. 18, 2024	Jan. 31, 2024	Dec. 31, 2023	Mar. 31, 2024	Dec. 31, 2023	Dec. 31, 2023	Dec. 31, 2022
Investment Company, Changes in Net Assets [Line Items]
Distribution to shareholders (in dollars per share)		$ 0.0034	$ 0.0609		$ 0.0643
Annualized distribution rate (percent)					7.50%
Net asset value per common share at period end (in USD per share)			$ 3.43	$ 3.47	$ 3.43	$ 3.43	$ 3.88
Net asset value common share percentage				2.50%
Short-term and long-term capital loss carryforwards			$ 1,518,431,000	$ 73,711,000	$ 1,518,431,000	$ 1,518,431,000
Unrealized gain			148,817,000	135,476,000	148,817,000	148,817,000
Unrealized loss			213,339,000	235,643,000	213,339,000	213,339,000
Income tax purposes			1,587,709,000	1,901,617,000	1,587,709,000	1,587,709,000
Net unrealized appreciation (depreciation)			(64,513,000)	(100,345,000)	(64,513,000)	(64,513,000)
Subsidiaries
Investment Company, Changes in Net Assets [Line Items]
Deferred tax asset			142,608,000	161,094,000	142,608,000	142,608,000
Deferred tax liability			2,595,000	0	2,595,000	2,595,000
Valuation allowances on deferred tax assets			$ 140,013,000	161,094,000	$ 140,013,000	140,013,000
Current income tax				$ 0		$ 0
Subsequent Event
Investment Company, Changes in Net Assets [Line Items]
Distribution to shareholders (in dollars per share)	$ 0.0866
Annualized distribution rate (percent)	10%
Maximum cap on annualized distribution rate (percent)	15%

Distributions - Cash Distribu_2

Distributions - Cash Distributions on Common Stock (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
Distribution Amount
Net investment income		$ 1,549	$ 13,584
Short-term capital gains proceeds from the sale of assets		0	0
Long-term capital gains proceeds from the sale of assets		0	0
Total	[1]	$ 1,549	$ 13,584
Percentage
Net investment income		100%	100%
Short-term capital gains proceeds from the sale of assets		0%	0%
Long-term capital gains proceeds from the sale of assets		0%	0%
Total		100%	100%
Gross investment income attributable to cash income earned		94.50%	86.60%
Gross investment income attributable to paid-in-kind interest		2.40%	10.50%
Gross investment income attributable to non-cash accretion of discount		3.10%	2.90%

[1] See Note 5 for a discussion of the sources of distributions paid by the Company.

Financial Instruments - Narrati

Financial Instruments - Narrative (Details) - USD ($) $ in Thousands		3 Months Ended
	Feb. 15, 2024	Mar. 31, 2024
Loan Total Return Swap Financing \| Loans Payable
Derivative [Line Items]
Utilization fee (percent)	0.85%
Minimum usage threshold amount	$ 100,000
Loan Total Return Swap Financing \| Loans Payable \| Secured Overnight Financing Rate (SOFR)
Derivative [Line Items]
Basis spread on variable rate (percent)	1.65%
Nomura Total Return Swap
Derivative [Line Items]
Term of contract		3 years
Nomura Total Return Swap \| Nomura Global Financial Products, Inc.
Derivative [Line Items]
Average monthly notional amount		$ 38,984
Nomura Total Return Swap \| BNPP TRS
Derivative [Line Items]
Average monthly notional amount		$ 52,462

Financial Instruments - Fair Va

Financial Instruments - Fair Value of Open Swap Contracts (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Derivative [Line Items]
Derivative Assets	$ 196	$ 0
Derivative Liabilities	0	0
BNP Paribas
Derivative [Line Items]
Derivative Assets	196
Derivative Liabilities	0
Nomura Total Return Swap \| Nomura Global Financial Products, Inc.
Derivative [Line Items]
Derivative Assets	0	0
Derivative Liabilities	0	0
Nomura Total Return Swap \| BNP Paribas
Derivative [Line Items]
Derivative Assets	196	0
Derivative Liabilities	$ 0	$ 0

Financial Instruments - Stateme

Financial Instruments - Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Net Realized Gains (Losses)	$ 2,327	$ 12
Net Change in Unrealized  Appreciation (Depreciation)	196	1,077
Commodity Fixed Price Swaps—Crude Oil
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Net Realized Gains (Losses)	0	(100)
Net Change in Unrealized  Appreciation (Depreciation)	0	733
Commodity Fixed Price Swaps—Natural Gas
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Net Realized Gains (Losses)	0	112
Net Change in Unrealized  Appreciation (Depreciation)	0	344
Nomura Total Return Swap \| Nomura Global Financial Products, Inc.
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Net Realized Gains (Losses)	2,302	0
Net Change in Unrealized  Appreciation (Depreciation)	0	0
Nomura Total Return Swap \| BNP Paribas
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Net Realized Gains (Losses)	25	0
Net Change in Unrealized  Appreciation (Depreciation)	$ 196	$ 0

Financial Instruments - Derivat

Financial Instruments - Derivative Assets and Liabilities by Counterparty (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Derivatives, Fair Value [Line Items]
Derivative Assets	$ 196	$ 0
Derivative Liabilities	0	$ 0
BNP Paribas
Derivatives, Fair Value [Line Items]
Derivative Assets	196
Derivative Liabilities	0
Net Value of Derivatives	196
Non-Cash Collateral (Received) Pledged	0
Cash Collateral (Received) Pledged	0
Net Amount of Derivative Assets (Liabilities)	$ 196

Investment Portfolio - Schedule

Investment Portfolio - Schedule Of Investment Portfolio At Cost And Fair Value (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2024		Dec. 31, 2023
Schedule of Investments [Line Items]
Amortized Cost	$ 1,857,014	[1]	$ 1,543,925	[2]
Fair Value	1,801,272	[1],[3]	1,523,196	[2],[4]
Net Senior Secured Loans—First Lien
Schedule of Investments [Line Items]
Amortized Cost	1,031,295	[1]	878,013	[2]
Fair Value	962,663	[1],[3]	825,158	[2],[4]
Net Senior Secured Loans—Second Lien
Schedule of Investments [Line Items]
Amortized Cost	81,646	[1]	55,064
Fair Value	81,936	[1],[3]	54,424
Senior Secured Bonds
Schedule of Investments [Line Items]
Amortized Cost	96,035	[1]	82,793
Fair Value	98,436	[1],[3]	84,468	[4]
Unsecured Debt
Schedule of Investments [Line Items]
Amortized Cost	20,329		0
Fair Value	20,329		0
Preferred Equity
Schedule of Investments [Line Items]
Amortized Cost	246,345	[1],[5]	252,450	[2],[6]
Fair Value	324,731	[1],[3],[5]	259,990	[2],[4],[6]
Sustainable Infrastructure Investments, LLC
Schedule of Investments [Line Items]
Amortized Cost	43,150	[1]	43,150	[2]
Fair Value	40,830	[1],[3]	39,427	[2],[4]
Equity/Other
Schedule of Investments [Line Items]
Amortized Cost	211,451		211,461
Fair Value	145,522		238,729
Short-Term Investments
Schedule of Investments [Line Items]
Amortized Cost	126,763	[1]	20,994	[2]
Fair Value	$ 126,825	[1],[3]	$ 21,000	[2],[4]
Percentage of Portfolio \| Customer Concentration Risk \| Net Senior Secured Loans—First Lien
Schedule of Investments [Line Items]
Percentage of Portfolio	53%		54%
Percentage of Portfolio \| Customer Concentration Risk \| Net Senior Secured Loans—Second Lien
Schedule of Investments [Line Items]
Percentage of Portfolio	5%		4%
Percentage of Portfolio \| Customer Concentration Risk \| Senior Secured Bonds
Schedule of Investments [Line Items]
Percentage of Portfolio	6%		5%
Percentage of Portfolio \| Customer Concentration Risk \| Unsecured Debt
Schedule of Investments [Line Items]
Percentage of Portfolio	1%		0%
Percentage of Portfolio \| Customer Concentration Risk \| Preferred Equity
Schedule of Investments [Line Items]
Percentage of Portfolio	18%		17%
Percentage of Portfolio \| Customer Concentration Risk \| Sustainable Infrastructure Investments, LLC
Schedule of Investments [Line Items]
Percentage of Portfolio	2%		3%
Percentage of Portfolio \| Customer Concentration Risk \| Equity/Other
Schedule of Investments [Line Items]
Percentage of Portfolio	8%		16%
Percentage of Portfolio \| Customer Concentration Risk \| Short-Term Investments
Schedule of Investments [Line Items]
Percentage of Portfolio	7%		1%
Percentage of Portfolio \| Customer Concentration Risk \| Total Investments
Schedule of Investments [Line Items]
Percentage of Portfolio	100%		100%

[1]Security may be an obligation of one or more entities affiliated with the named company.[2]Security may be an obligation of one or more entities affiliated with the named company.[3]See Note 8 for additional information regarding the fair value of the Company’s financial instruments.[4]See Note 8 for additional information regarding the fair value of the Company’s financial instruments.[5]Includes $59,698 held in Allspring Government Money Market Fund with a 7-day yield of 5.2% as of March 31, 2024.[6]Security held within EP Northern Investments, LLC, a wholly-owned subsidiary of the Company.

Investment Portfolio - Narrativ

Investment Portfolio - Narrative (Details) $ in Thousands, $ in Thousands				3 Months Ended
		Jan. 02, 2020 USD ($)	Jan. 02, 2020 CAD ($)	Mar. 31, 2024 USD ($) company investment		Mar. 31, 2024 CAD ($) company investment		Dec. 31, 2023 USD ($) investment company		Dec. 31, 2023 CAD ($) investment company
Investment, Identifier [Axis]: AI Aqua Merger Sub, Inc., Capital Goods 1
Schedule of Investments [Line Items]
Principal amount				$ 17,948	[1],[2]			$ 16,522	[3],[4],[5]
Floor rate				0.50%	[2],[6]	0.50%	[2],[6]	0.50%	[4],[5],[7]	0.50%	[4],[5],[7]
Variable rate (percent)				4.25%	[2],[6]	4.25%	[2],[6]	4.25%	[4],[5],[7]	4.25%	[4],[5],[7]
Investment, Identifier [Axis]: AI Aqua Merger Sub, Inc., Capital Goods 2
Schedule of Investments [Line Items]
Principal amount				$ 2,052	[1],[8]			$ 3,478	[3],[5],[9]
Floor rate				0.50%	[6],[8]	0.50%	[6],[8]	0.50%	[5],[7],[9]	0.50%	[5],[7],[9]
Variable rate (percent)				4.25%	[6],[8]	4.25%	[6],[8]	4.25%	[5],[7],[9]	4.25%	[5],[7],[9]
Investment, Identifier [Axis]: AIRRO (Mauritius) Holdings II, Energy—Power
Schedule of Investments [Line Items]
Principal amount				$ 14,865	[1],[10],[11],[12]			$ 22,856	[3],[13],[14],[15]
Floor rate				1.50%	[6],[10],[11],[12]	1.50%	[6],[10],[11],[12]	1.50%	[7],[13],[14],[15]	1.50%	[7],[13],[14],[15]
Variable rate (percent)				4%	[6],[10],[11],[12]	4%	[6],[10],[11],[12]	4%	[7],[13],[14],[15]	4%	[7],[13],[14],[15]
Investment, Identifier [Axis]: Acrisure, LLC, Insurance
Schedule of Investments [Line Items]
Principal amount				$ 25,112	[1],[2]			$ 20,175	[3],[4]
Variable rate (percent)				4.50%	[2],[6]	4.50%	[2],[6]	4.50%	[4],[7]	4.50%	[4],[7]
Investment, Identifier [Axis]: Aimbridge Acquisition Co. Inc., Consumer Services
Schedule of Investments [Line Items]
Principal amount				$ 26,735	[1],[2]			$ 21,805	[3],[4]
Variable rate (percent)				3.75%	[2],[6]	3.75%	[2],[6]	3.75%	[4],[7]	3.75%	[4],[7]
Investment, Identifier [Axis]: Allegiant Travel Co., Transportation
Schedule of Investments [Line Items]
Principal amount				$ 10,601	[1],[12]			$ 10,601	[3],[15]
Investment, Identifier [Axis]: Allied Universal Holdco LLC, Consumer Services 1
Schedule of Investments [Line Items]
Principal amount				$ 14,420	[1],[2]			$ 9,975	[3],[4]
Floor rate				0.50%	[2],[6]	0.50%	[2],[6]	0.50%	[4],[7]	0.50%	[4],[7]
Variable rate (percent)				4.75%	[2],[6]	4.75%	[2],[6]	4.75%	[4],[7]	4.75%	[4],[7]
Investment, Identifier [Axis]: Allied Universal Holdco LLC, Consumer Services 2
Schedule of Investments [Line Items]
Principal amount				$ 9,904	[1],[2]			$ 9,929	[3],[4]
Floor rate				0.50%	[2],[6]	0.50%	[2],[6]	0.50%	[4],[7]	0.50%	[4],[7]
Variable rate (percent)				3.75%	[2],[6]	3.75%	[2],[6]	3.75%	[4],[7]	3.75%	[4],[7]
Investment, Identifier [Axis]: Allied Wireline Services, LLC, Energy—Service & Equipment
Schedule of Investments [Line Items]
Principal amount				$ 70,277	[1],[10],[16],[17],[18]			$ 70,277	[3],[13],[19],[20],[21]
Investment, Identifier [Axis]: American Auto Auction Group, LLC, Capital Goods
Schedule of Investments [Line Items]
Principal amount				$ 23,913	[1],[2],[22]			$ 9,975	[3],[4]
Floor rate				0.80%	[2],[6],[22]	0.80%	[2],[6],[22]	0.80%	[4],[7]	0.80%	[4],[7]
Variable rate (percent)				5%	[2],[6],[22]	5%	[2],[6],[22]	5%	[4],[7]	5%	[4],[7]
Investment, Identifier [Axis]: Aretec Escrow Issuer Inc., Financial Services
Schedule of Investments [Line Items]
Principal amount				$ 7,000	[1],[2]			$ 7,000	[3],[4]
Investment, Identifier [Axis]: Aretec Group, Inc., Financial Services
Schedule of Investments [Line Items]
Principal amount				$ 6,834	[1],[2],[22]			$ 9,352	[3],[4],[5]
Variable rate (percent)				4.50%	[2],[6],[22]	4.50%	[2],[6],[22]	4.50%	[4],[5],[7]	4.50%	[4],[5],[7]
Investment, Identifier [Axis]: Auris Luxembourg III S.a r.l, Health Care Equipment & Services
Schedule of Investments [Line Items]
Principal amount				$ 20,234	[1],[2],[12]			$ 20,287	[3],[4],[15]
Variable rate (percent)				3.75%	[2],[6],[12]	3.75%	[2],[6],[12]	3.75%	[4],[7],[15]	3.75%	[4],[7],[15]
Investment, Identifier [Axis]: Aveanna Healthcare LLC, Health Care Equipment & Services
Schedule of Investments [Line Items]
Principal amount				$ 20,855	[1],[2]			$ 15,909	[3],[4]
Floor rate				0.50%	[2],[6]	0.50%	[2],[6]	0.50%	[4],[7]	0.50%	[4],[7]
Variable rate (percent)				3.75%	[2],[6]	3.75%	[2],[6]	3.75%	[4],[7]	3.75%	[4],[7]
Investment, Identifier [Axis]: BCPE Empire Holdings, Inc., Consumer Services
Schedule of Investments [Line Items]
Principal amount				$ 22,400	[1],[2],[22]			$ 24,900	[3],[4]
Floor rate				0.50%	[2],[6],[22]	0.50%	[2],[6],[22]	0.50%	[4],[7]	0.50%	[4],[7]
Variable rate (percent)				4%	[2],[6],[22]	4%	[2],[6],[22]	4.75%	[4],[7]	4.75%	[4],[7]
Investment, Identifier [Axis]: Bridge Street Warehouse CLO IV Ltd., Financial Services
Schedule of Investments [Line Items]
Principal amount	[1],[10],[12],[23],[24]			$ 20,000
Investment, Identifier [Axis]: CCS-CMGC Holdings, Inc., Health Care Equipment & Services
Schedule of Investments [Line Items]
Principal amount				$ 27,768	[1],[2]			$ 21,465	[3],[4]
Variable rate (percent)				5.50%	[2],[6]	5.50%	[2],[6]	5.50%	[4],[7]	5.50%	[4],[7]
Investment, Identifier [Axis]: CPM Holdings, Inc., Capital Goods
Schedule of Investments [Line Items]
Principal amount				$ 24,938	[1],[2]			$ 20,000	[3],[4]
Floor rate				0.50%	[2],[6]	0.50%	[2],[6]	0.50%	[4],[7]	0.50%	[4],[7]
Variable rate (percent)				4.50%	[2],[6]	4.50%	[2],[6]	4.50%	[4],[7]	4.50%	[4],[7]
Investment, Identifier [Axis]: CT Technologies Intermediate Holdings, Inc., Health Care Equipment & Services
Schedule of Investments [Line Items]
Principal amount	[1],[2]			$ 9,974
Floor rate	[2],[6]			0.80%		0.80%
Variable rate (percent)	[2],[6]			4.25%		4.25%
Investment, Identifier [Axis]: Charlotte Buyer, Inc., Health Care Equipment & Services
Schedule of Investments [Line Items]
Principal amount				$ 17,800	[1],[2]			$ 19,845	[3],[4],[5]
Floor rate				0.50%	[2],[6]	0.50%	[2],[6]	0.50%	[4],[5],[7]	0.50%	[4],[5],[7]
Variable rate (percent)				5.25%	[2],[6]	5.25%	[2],[6]	5.25%	[4],[5],[7]	5.25%	[4],[5],[7]
Investment, Identifier [Axis]: CircusTrix Holdings, LLC, Consumer Services 1
Schedule of Investments [Line Items]
Principal amount				$ 20,863	[1],[2],[10]			$ 20,915	[3],[4],[13]
Floor rate				1%	[2],[6],[10]	1%	[2],[6],[10]	1%	[4],[7],[13]	1%	[4],[7],[13]
Variable rate (percent)				6.50%	[2],[6],[10]	6.50%	[2],[6],[10]	6.75%	[4],[7],[13]	6.75%	[4],[7],[13]
Investment, Identifier [Axis]: CircusTrix Holdings, LLC, Consumer Services 2
Schedule of Investments [Line Items]
Principal amount				$ 2,688	[1],[8],[10]			$ 2,688	[3],[9],[13]
Floor rate				1%	[6],[8],[10]	1%	[6],[8],[10]	1%	[7],[9],[13]	1%	[7],[9],[13]
Variable rate (percent)				6.50%	[6],[8],[10]	6.50%	[6],[8],[10]	6.75%	[7],[9],[13]	6.75%	[7],[9],[13]
Investment, Identifier [Axis]: CircusTrix Holdings, LLC, Consumer Services 3
Schedule of Investments [Line Items]
Principal amount				$ 1,344	[1],[8],[10]			$ 1,344	[3],[9],[13]
Floor rate				1%	[6],[8],[10]	1%	[6],[8],[10]	1%	[7],[9],[13]	1%	[7],[9],[13]
Variable rate (percent)				6.50%	[6],[8],[10]	6.50%	[6],[8],[10]	6.75%	[7],[9],[13]	6.75%	[7],[9],[13]
Investment, Identifier [Axis]: Cirque Du Soleil Holding USA Newco, Inc., Financial Services
Schedule of Investments [Line Items]
Principal amount				$ 8,365	[1],[2]			$ 6,387	[3],[4],[5]
Floor rate				0.50%	[2],[6]	0.50%	[2],[6]	0.50%	[4],[5],[7]	0.50%	[4],[5],[7]
Variable rate (percent)				4.25%	[2],[6]	4.25%	[2],[6]	4.25%	[4],[5],[7]	4.25%	[4],[5],[7]
Investment, Identifier [Axis]: Citizen Energy Operating, LLC, Energy—Upstream
Schedule of Investments [Line Items]
Principal amount				$ 34,000	[1],[2],[10]			$ 35,000	[3],[4],[13]
Floor rate				1%	[2],[6],[10]	1%	[2],[6],[10]	1%	[4],[7],[13]	1%	[4],[7],[13]
Variable rate (percent)				7.65%	[2],[6],[10]	7.65%	[2],[6],[10]	7.65%	[4],[7],[13]	7.65%	[4],[7],[13]
Investment, Identifier [Axis]: Clear Channel Outdoor Holdings, Inc., Media & Entertainment
Schedule of Investments [Line Items]
Principal amount				$ 12,500	[1],[2],[12]			$ 20,000	[3],[4],[15]
Variable rate (percent)				4%	[2],[6],[12]	4%	[2],[6],[12]	3.50%	[4],[7],[15]	3.50%	[4],[7],[15]
Investment, Identifier [Axis]: Clydesdale Acquisition Holdings Inc., Financial Services
Schedule of Investments [Line Items]
Principal amount	[1],[2]			$ 17,405
Floor rate	[2],[6]			0.50%		0.50%
Variable rate (percent)	[2],[6]			3.75%		3.75%
Investment, Identifier [Axis]: Clydesdale Acquisition Holdings Inc., Financials Services
Schedule of Investments [Line Items]
Principal amount	[3],[4]							$ 19,949
Floor rate	[4],[7]							0.50%		0.50%
Variable rate (percent)	[4],[7]							4.18%		4.18%
Investment, Identifier [Axis]: Cox Oil Offshore, LLC, Volumetric Production Payments, Energy—Upstream
Schedule of Investments [Line Items]
Principal amount	[3],[13],[25],[26]							$ 100,000
Investment, Identifier [Axis]: Crown SubSea Communication Holding, Inc., Capital Goods
Schedule of Investments [Line Items]
Principal amount	[1],[2]			$ 6,000
Floor rate	[2],[6]			0.80%		0.80%
Variable rate (percent)	[2],[6]			4.75%		4.75%
Investment, Identifier [Axis]: Crown SubSea Communications Holding, Inc., Capital Goods 1
Schedule of Investments [Line Items]
Principal amount	[3],[4],[5]							$ 4,500
Floor rate	[4],[5],[7]							0.80%		0.80%
Variable rate (percent)	[4],[5],[7]							5%		5%
Investment, Identifier [Axis]: Crown SubSea Communications Holding, Inc., Capital Goods 2
Schedule of Investments [Line Items]
Principal amount	[3],[4],[5]							$ 5,430
Floor rate	[4],[5],[7]							0.80%		0.80%
Variable rate (percent)	[4],[5],[7]							5.25%		5.25%
Investment, Identifier [Axis]: Delivery Hero Finco LLC, Consumer Services
Schedule of Investments [Line Items]
Principal amount	[1],[12],[22]			$ 20,000
Floor rate	[6],[12],[22]			0.50%		0.50%
Variable rate (percent)	[6],[12],[22]			5%		5%
Investment, Identifier [Axis]: Digicel International Finance Ltd., Telecommunication Services
Schedule of Investments [Line Items]
Principal amount	[1],[2]			$ 20,000
Floor rate	[2],[6]			0.50%		0.50%
Variable rate (percent)	[2],[6]			5.15%		5.15%
Investment, Identifier [Axis]: Engineered Machinery Holdings, Inc., Capital Goods
Schedule of Investments [Line Items]
Principal amount				$ 24,860	[1],[2]			$ 19,924	[3],[4]
Floor rate				0.80%	[2],[6]	0.80%	[2],[6]	0.80%	[4],[7]	0.80%	[4],[7]
Variable rate (percent)				3.75%	[2],[6]	3.75%	[2],[6]	3.50%	[4],[7]	3.50%	[4],[7]
Investment, Identifier [Axis]: FR XIII PAA Holdings HoldCo, LLC, Energy—Midstream
Schedule of Investments [Line Items]
Principal amount	[3],[4],[13]							$ 17,047
Floor rate	[4],[7],[13]							0.50%		0.50%
Variable rate (percent)	[4],[7],[13]							7.50%		7.50%
Investment, Identifier [Axis]: First Brands Group, LLC, Automobiles & Components
Schedule of Investments [Line Items]
Principal amount				$ 24,841	[1],[2]			$ 19,905	[3],[4]
Floor rate				1%	[2],[6]	1%	[2],[6]	1%	[4],[7]	1%	[4],[7]
Variable rate (percent)				5%	[2],[6]	5%	[2],[6]	5%	[4],[7]	5%	[4],[7]
Investment, Identifier [Axis]: Full House Resorts, Inc., Consumer Services
Schedule of Investments [Line Items]
Principal amount				$ 25,742	[1],[2]			$ 20,742	[3],[4]
Investment, Identifier [Axis]: GasLog Ltd., Energy—Midstream
Schedule of Investments [Line Items]
Principal amount				$ 13,951	[1],[10],[12]			13,951	[3],[13],[15]
Variable rate (percent)	[6],[10],[12]			7.80%		7.80%
Investment, Identifier [Axis]: Global Tel Link Corp., Technology Hardware & Equipment
Schedule of Investments [Line Items]
Principal amount	[1],[2],[22]			$ 14,031
Variable rate (percent)	[2],[6],[22]			4.25%		4.25%
Investment, Identifier [Axis]: Gold Rush Amusements, Inc., Consumer Services
Schedule of Investments [Line Items]
Principal amount				$ 30,596	[1],[2],[10]			$ 30,673	[3],[4],[13]
Floor rate				2%	[2],[6],[10]	2%	[2],[6],[10]	2%	[4],[7],[13]	2%	[4],[7],[13]
Variable rate (percent)				7.50%	[2],[6],[10]	7.50%	[2],[6],[10]	7.50%	[4],[7],[13]	7.50%	[4],[7],[13]
Investment, Identifier [Axis]: Goodnight Water Solutions, LLC, Energy—Midstream
Schedule of Investments [Line Items]
Principal amount				$ 14,328	[1],[2],[10]			$ 14,516	[3],[4],[13]
Floor rate				0.50%	[2],[6],[10]	0.50%	[2],[6],[10]	0.50%	[4],[7],[13]	0.50%	[4],[7],[13]
Variable rate (percent)				7%	[2],[6],[10]	7%	[2],[6],[10]	7%	[4],[7],[13]	7%	[4],[7],[13]
Investment, Identifier [Axis]: Guardian US Holdco, LLC, Financial Services
Schedule of Investments [Line Items]
Principal amount				$ 24,863	[1],[2]			$ 19,925	[3],[4]
Floor rate				0.50%	[2],[6]	0.50%	[2],[6]	0.50%	[4],[7]	0.50%	[4],[7]
Variable rate (percent)				3.50%	[2],[6]	3.50%	[2],[6]	4%	[4],[7]	4%	[4],[7]
Investment, Identifier [Axis]: Guitar Center, Inc., Consumer Discretionary Distribution & Retail
Schedule of Investments [Line Items]
Principal amount				$ 23,568	[1],[2]			$ 20,000	[3],[4]
Investment, Identifier [Axis]: Knowlton Development Corporation Inc., Household & Personal Products
Schedule of Investments [Line Items]
Principal amount				$ 26,000	[1],[2]			$ 21,000	[3],[4]
Variable rate (percent)				5%	[2],[6]	5%	[2],[6]	5%	[4],[7]	5%	[4],[7]
Investment, Identifier [Axis]: LABL, Inc., Commercial & Professional Services
Schedule of Investments [Line Items]
Principal amount	[1],[2]			$ 24,801
Floor rate	[2],[6]			0.50%		0.50%
Variable rate (percent)	[2],[6]			5%		5%
Investment, Identifier [Axis]: LABL, Inc., Commerical & Professional Services
Schedule of Investments [Line Items]
Principal amount	[3],[4]							$ 19,864
Floor rate	[4],[7]							0.50%		0.50%
Variable rate (percent)	[4],[7]							5%		5%
Investment, Identifier [Axis]: LaserShip, Inc., Transportation
Schedule of Investments [Line Items]
Principal amount	[1],[2]			$ 6,982
Floor rate	[2],[6]			0.80%		0.80%
Variable rate (percent)	[2],[6]			4.50%		4.50%
Investment, Identifier [Axis]: Learning Care Group No. 2 Inc., Consumer Services
Schedule of Investments [Line Items]
Principal amount				$ 21,895	[1],[2]			$ 19,950	[3],[4]
Floor rate				0.50%	[2],[6]	0.50%	[2],[6]	0.50%	[4],[7]	0.50%	[4],[7]
Variable rate (percent)				4.75%	[2],[6]	4.75%	[2],[6]	4.75%	[4],[7]	4.75%	[4],[7]
Investment, Identifier [Axis]: MBS Services Holdings, LLC, Commercial & Professional Services
Schedule of Investments [Line Items]
Principal amount	[1],[10]			$ 28,622
Investment, Identifier [Axis]: Mavis Tire Express Services TopCo, L.P., Consumer Discretionary Distribution & Retail
Schedule of Investments [Line Items]
Principal amount				$ 17,349	[1],[2]			$ 19,893	[3],[4]
Floor rate				0.80%	[2],[6]	0.80%	[2],[6]	0.80%	[4],[7]	0.80%	[4],[7]
Variable rate (percent)				3.75%	[2],[6]	3.75%	[2],[6]	4%	[4],[7]	4%	[4],[7]
Investment, Identifier [Axis]: Navios Logistics Finance, Inc., Transportation
Schedule of Investments [Line Items]
Principal amount				$ 25,000	[1],[2],[12]			$ 20,000	[3],[4],[15]
Investment, Identifier [Axis]: Nephron Pharmaceuticals Corp., Pharmaceuticals, Biotechnology & Life Sciences
Schedule of Investments [Line Items]
Principal amount				$ 19,925	[1],[10]			$ 20,000	[3],[13]
Floor rate				1.50%	[6],[10]	1.50%	[6],[10]	1.50%	[7],[13]	1.50%	[7],[13]
Variable rate (percent)				9%	[6],[10]	9%	[6],[10]	9%	[7],[13]	9%	[7],[13]
Investment, Identifier [Axis]: Osaic Holdings, Inc., Financial Services
Schedule of Investments [Line Items]
Principal amount	[1],[2],[22]			$ 4,988
Variable rate (percent)	[2],[6],[22]			4.50%		4.50%
Investment, Identifier [Axis]: Permian Production Holdings, LLC, Energy—Upstream
Schedule of Investments [Line Items]
Principal amount				$ 4,060	[1],[10],[24]			$ 4,864	[3],[13],[27]
Investment, Identifier [Axis]: Phoenix Guarantor Inc., Financial Services
Schedule of Investments [Line Items]
Principal amount	[3],[4],[5]							$ 19,923
Variable rate (percent)	[4],[5],[7]							3.50%		3.50%
Investment, Identifier [Axis]: Plainfield Renewable Energy Holdings LLC, Energy—Power 2
Schedule of Investments [Line Items]
Principal amount	[1],[10],[16],[17]			4,218
Investment, Identifier [Axis]: Plainfield Renewable Energy Holdings LLC, Energy—Power 1
Schedule of Investments [Line Items]
Principal amount				13,936	[1],[10],[16],[17]			$ 13,297	[3],[13],[19],[20]
Investment, Identifier [Axis]: Plainfield Renewable Energy Holdings LLC, Energy—Power 2
Schedule of Investments [Line Items]
Principal amount	[3],[13],[19],[20]							4,015
Investment, Identifier [Axis]: Plainfield Renewable Energy Holdings LLC, Letter of Credit, Energy—Power
Schedule of Investments [Line Items]
Principal amount				2,709	[1],[8],[10]			2,709	[3],[9],[13]
Investment, Identifier [Axis]: Pretium PKG Holdings, Inc., Materials
Schedule of Investments [Line Items]
Principal amount				$ 32,378	[1],[2]			$ 30,118	[3],[4]
Floor rate				1%	[2],[6]	1%	[2],[6]	1%	[4],[7]	1%	[4],[7]
Variable rate (percent)				2.50%	[2],[6]	2.50%	[2],[6]	5%	[4],[7]	5%	[4],[7]
Investment, Identifier [Axis]: Pro Mach Group, Inc., Capital Goods
Schedule of Investments [Line Items]
Principal amount				$ 17,424	[1],[2]			$ 19,924	[3],[4]
Floor rate				1%	[2],[6]	1%	[2],[6]	1%	[4],[7]	1%	[4],[7]
Variable rate (percent)				3.75%	[2],[6]	3.75%	[2],[6]	4%	[4],[7]	4%	[4],[7]
Investment, Identifier [Axis]: Proampac PG Borrower LLC, Materials
Schedule of Investments [Line Items]
Principal amount				$ 22,942	[1],[2]			$ 20,000	[3],[4]
Floor rate				0.80%	[2],[6]	0.80%	[2],[6]	0.80%	[4],[7]	0.80%	[4],[7]
Variable rate (percent)				4.50%	[2],[6]	4.50%	[2],[6]	4.50%	[4],[7]	4.50%	[4],[7]
Investment, Identifier [Axis]: RealTruck Group, Inc., Automobiles & Components
Schedule of Investments [Line Items]
Principal amount	[1],[2]			$ 24,885
Floor rate	[2],[6]			0.80%		0.80%
Variable rate (percent)	[2],[6]			3.50%		3.50%
Investment, Identifier [Axis]: Realtruck Group, Inc., Automobiles & Components
Schedule of Investments [Line Items]
Principal amount	[3],[4],[5]							$ 19,956
Floor rate	[4],[5],[7]							0.80%		0.80%
Variable rate (percent)	[4],[5],[7]							3.50%		3.50%
Investment, Identifier [Axis]: Ryan, LLC, Commercial & Professional Services 1
Schedule of Investments [Line Items]
Principal amount	[1],[2]			$ 9,844
Floor rate	[2],[6]			0.50%		0.50%
Variable rate (percent)	[2],[6]			4.50%		4.50%
Investment, Identifier [Axis]: Ryan, LLC, Commercial & Professional Services 2
Schedule of Investments [Line Items]
Principal amount	[1],[8]			$ 1,036
Floor rate	[6],[8]			0.50%		0.50%
Variable rate (percent)	[6],[8]			4.50%		4.50%
Investment, Identifier [Axis]: Ryan, LLC, Commerical & Professional Services 1
Schedule of Investments [Line Items]
Principal amount	[3],[4],[5]							$ 9,844
Floor rate	[4],[5],[7]							0.50%		0.50%
Variable rate (percent)	[4],[5],[7]							4.50%		4.50%
Investment, Identifier [Axis]: Ryan, LLC, Commerical & Professional Services 2
Schedule of Investments [Line Items]
Principal amount	[3],[5],[9]							$ 1,036
Floor rate	[5],[7],[9]							0.50%		0.50%
Variable rate (percent)	[5],[7],[9]							4.50%		4.50%
Investment, Identifier [Axis]: SRS Distribution Inc., Capital Goods
Schedule of Investments [Line Items]
Principal amount				$ 24,860	[1],[2]			$ 19,924	[3],[4],[5]
Floor rate				0.50%	[2],[6]	0.50%	[2],[6]	0.50%	[4],[5],[7]	0.50%	[4],[5],[7]
Variable rate (percent)				3.50%	[2],[6]	3.50%	[2],[6]	3.50%	[4],[5],[7]	3.50%	[4],[5],[7]
Investment, Identifier [Axis]: ST EIP Holdings Inc., Energy—Midstream
Schedule of Investments [Line Items]
Principal amount				$ 10,311	[1],[2],[10]			$ 10,365	[3],[4],[13]
Investment, Identifier [Axis]: Sustainable Infrastructure Investments, LLC, Energy—Power
Schedule of Investments [Line Items]
Principal amount				60,603	[1],[10],[12],[18]			60,603	[13],[15],[21]
Investment, Identifier [Axis]: TKC Holdings, Inc., Consumer Staples Distribution & Retail
Schedule of Investments [Line Items]
Principal amount				$ 24,536	[1],[2]			$ 19,650	[3],[4]
Floor rate				1%	[2],[6]	1%	[2],[6]	1%	[4],[7]	1%	[4],[7]
Variable rate (percent)				5.50%	[2],[6]	5.50%	[2],[6]	5.50%	[4],[7]	5.50%	[4],[7]
Investment, Identifier [Axis]: Tenrgys, LLC, Energy—Upstream
Schedule of Investments [Line Items]
Principal amount				$ 20,537	[1],[2],[10]			$ 20,537	[3],[4],[13]
Floor rate				1%	[2],[6],[10]	1%	[2],[6],[10]	1%	[4],[7],[13]	1%	[4],[7],[13]
Variable rate (percent)				7.50%	[2],[6],[10]	7.50%	[2],[6],[10]	7.50%	[4],[7],[13]	7.50%	[4],[7],[13]
Investment, Identifier [Axis]: TruGreen, LP, Commercial & Professional Services
Schedule of Investments [Line Items]
Principal amount				$ 24,846	[1],[2]			$ 19,910	[3],[4]
Floor rate				0.80%	[2],[6]	0.80%	[2],[6]	0.80%	[4],[7]	0.80%	[4],[7]
Variable rate (percent)				4%	[2],[6]	4%	[2],[6]	4%	[4],[7]	4%	[4],[7]
Investment, Identifier [Axis]: U.S. Treasury Bills, U.S. Treasury 1
Schedule of Investments [Line Items]
Principal amount	[28],[29]			$ 100,000
Investment, Identifier [Axis]: U.S. Treasury Bills, U.S. Treasury 2
Schedule of Investments [Line Items]
Principal amount	[28],[29]			27,000
Investment, Identifier [Axis]: U.S. Treasury Bills, U.S. Treasury Bills
Schedule of Investments [Line Items]
Principal amount	[30]							$ 21,000
Investment, Identifier [Axis]: WMK, LLC, Consumer Discretionary Distribution & Retail 1
Schedule of Investments [Line Items]
Principal amount	[1],[2],[10]			$ 29,833
Floor rate	[2],[6],[10]			3%		3%
Variable rate (percent)	[2],[6],[10]			6.50%		6.50%
Investment, Identifier [Axis]: WMK, LLC, Consumer Discretionary Distribution & Retail 2
Schedule of Investments [Line Items]
Principal amount	[1],[8],[10]			$ 5,167
Floor rate	[6],[8],[10]			3%		3%
Variable rate (percent)	[6],[8],[10]			6.50%		6.50%
Investment, Identifier [Axis]: Warren Resources, Inc., Energy—Upstream
Schedule of Investments [Line Items]
Principal amount				$ 23,883	[1],[2],[10],[18]			$ 23,823	[3],[4],[13],[21]
Floor rate				1%	[2],[6],[10],[18]	1%	[2],[6],[10],[18]	1%	[4],[7],[13],[21]	1%	[4],[7],[13],[21]
Variable rate (percent)				9%	[2],[6],[10],[18]	9%	[2],[6],[10],[18]	9%	[4],[7],[13],[21]	9%	[4],[7],[13],[21]
Investment, Identifier [Axis]: Wattbridge Inc., Energy—Power
Schedule of Investments [Line Items]
Principal amount				$ 42,938	[1],[2],[10]			$ 42,938	[3],[4],[13]
Floor rate				1.80%	[2],[6],[10]	1.80%	[2],[6],[10]	1.80%	[4],[7],[13]	1.80%	[4],[7],[13]
Variable rate (percent)				9.85%	[2],[6],[10]	9.85%	[2],[6],[10]	9.85%	[4],[7],[13]	9.85%	[4],[7],[13]
Investment, Identifier [Axis]: Weber-Stephen Products LLC, Consumer Durables & Apparel
Schedule of Investments [Line Items]
Principal amount	[1],[2],[22]			$ 26,285
Floor rate	[2],[6],[22]			0.80%		0.80%
Variable rate (percent)	[2],[6],[22]			3.25%		3.25%
Sustainable Infrastructure Investments, LLC
Schedule of Investments [Line Items]
Aggregate sustainable infrastructure investments		$ 67,629	$ 5,430
Contributed capital to committed capital ratio		87.50%	87.50%
Percentage of voting control		50%	50%
Amount funded to joint venture				$ 43,150
Principal amount				153,837				$ 170,083
Debt				121,041				145,483
Sustainable Infrastructure Investments, LLC \| Investment, Identifier [Axis]: Blue Heron Intermediate Holdco I, LLC, Midstream
Schedule of Investments [Line Items]
Principal amount				$ 30,343				$ 30,661
Variable rate (percent)				1.88%		1.88%		1.88%		1.88%
Sustainable Infrastructure Investments, LLC \| Investment, Identifier [Axis]: Copper Mountain Solar 3, LLC, Renewables
Schedule of Investments [Line Items]
Principal amount				$ 16,104				$ 16,104
Variable rate (percent)				1.88%		1.88%		1.88%		1.88%
Sustainable Infrastructure Investments, LLC \| Investment, Identifier [Axis]: FLNG Liquefaction 2, LLC, Midstream
Schedule of Investments [Line Items]
Principal amount				$ 26,164				$ 26,567
Variable rate (percent)				1.50%		1.50%		1.50%		1.50%
Sustainable Infrastructure Investments, LLC \| Investment, Identifier [Axis]: Largest Portfolio Company Investment
Schedule of Investments [Line Items]
Principal amount				$ 57,227				$ 57,227
Sustainable Infrastructure Investments, LLC \| Investment, Identifier [Axis]: NES Hercules Class B Member, LLC, Renewables
Schedule of Investments [Line Items]
Principal amount				$ 23,999				$ 24,176
Variable rate (percent)				1.63%		1.63%		1.63%		1.63%
Sustainable Infrastructure Investments, LLC \| Investment, Identifier [Axis]: ST EIP Holdco LLC, Midstream
Schedule of Investments [Line Items]
Principal amount				$ 57,227				$ 57,227
Variable rate (percent)				2.50%		2.50%		2.50%		2.50%
Sustainable Infrastructure Investments, LLC \| Investment, Identifier [Axis]: Seine Funding, LLC
Schedule of Investments [Line Items]
Principal amount		$ 634,103
Floor rate		0%
Variable rate (percent)		1.20%
Sustainable Infrastructure Investments, LLC \| Investment, Identifier [Axis]: Top of the World Wind Energy LLC, Renewables
Schedule of Investments [Line Items]
Principal amount								$ 15,348
Variable rate (percent)								2.13%		2.13%
Sustainable Infrastructure Investments, LLC \| Imperial
Schedule of Investments [Line Items]
Contributed capital to committed capital ratio		12.50%	12.50%
Percentage of voting control		50%	50%
Sustainable Infrastructure Investments, LLC \| FS Energy And Power Fund
Schedule of Investments [Line Items]
Sustainable infrastructure investments, LLC entitled to a fee percentage		0.25%	0.25%
Sustainable Infrastructure Investments, LLC \| FS Specialty Lending Fund And Imperial Sustainable Infrustructure Investments, LLC
Schedule of Investments [Line Items]
Amount funded to joint venture				$ 49,313
Senior Secured Loan
Schedule of Investments [Line Items]
Number of senior secured loan investments \| investment				6		6		5		5
Unfunded commitment with amortized cost				$ 14,996				$ 11,232
Partnership Interest \| Sustainable Infrastructure Investments, LLC
Schedule of Investments [Line Items]
Unfunded commitment with amortized cost				$ 18,989		$ 858		$ 18,989		$ 858
Non-Controlled/Affiliated
Schedule of Investments [Line Items]
Number of investments in portfolio companies \| company				5		5		4		4
Controlled/affiliated
Schedule of Investments [Line Items]
Number of investments in portfolio companies \| company				3		3		3		3

[1]Denominated in U.S. dollars, unless otherwise noted.[2]Security or portion thereof held within FSSL Finance BB AssetCo LLC, a wholly-owned subsidiary of the Company, and is pledged as collateral supporting the obligations outstanding under the repurchase facility with Barclays Bank PLC (see Note 9).[3]Denominated in U.S. dollars, unless otherwise noted.[4]Security or portion thereof held within FSSL Finance BB AssetCo LLC, a wholly-owned subsidiary of the Company, and is pledged as collateral supporting the obligations outstanding under the repurchase facility with Barclays Bank PLC (see Note 9).[5]Security or portion thereof unsettled as of December 31, 2023.[6]Certain variable rate securities in the Company’s portfolio bear interest at a rate determined by a publicly disclosed base rate plus a basis point spread. As of March 31, 2024, the one-month and three-month Secured Overnight Financing Rate, or SOFR, or S, was 5.33% and 5.30%, respectively, and the Overnight Bank Funding Rate, or OBFR, was 5.33%. SOFR based contracts may include a credit spread adjustment that is charged in addition to the base rate and basis point spread. PIK means paid-in-kind. PIK income accruals may be adjusted based on the fair value of the underlying investment. Variable rate securities with no floor rate use the respective benchmark rate in all cases.[7]Certain variable rate securities in the Company’s portfolio bear interest at a rate determined by a publicly disclosed base rate plus a basis point spread. As of December 31, 2023, the one-month and three-month Secured Overnight Financing Rate, or SOFR, or S, was 5.35% and 5.33%, respectively, and the Overnight Bank Funding Rate, or OBFR, was 5.32%. SOFR based contracts may include a credit spread adjustment that is charged in addition to the base rate and basis point spread. PIK means paid-in-kind. PIK income accruals may be adjusted based on the fair value of the underlying investment. Variable rate securities with no floor rate use the respective benchmark rate in all cases.[8]Security is an unfunded commitment. The stated rate reflects the spread disclosed at the time of commitment and may not indicate the actual rate received upon funding.[9]Security is an unfunded commitment. The stated rate reflects the spread disclosed at the time of commitment and may not indicate the actual rate received upon funding.[10]Security is classified as Level 3 in the Company’s fair value hierarchy (see Note 8).[11]Security or portion thereof held within FS Power Investments II, LLC, a wholly-owned subsidiary of the Company.[12]The investment is not a qualifying asset under the Investment Company Act of 1940, as amended, or the 1940 Act. A business development company may not acquire any asset other than a qualifying asset, unless, at the time the acquisition is made, qualifying assets represent at least 70% of the business development company’s total assets. As of March 31, 2024, 75.7% of the Company’s total assets represented qualifying assets.[13]Security is classified as Level 3 in the Company’s fair value hierarchy (see Note 8).[14]Security or portion thereof held within FS Power Investments II, LLC, a wholly-owned subsidiary of the Company.[15]The investment is not a qualifying asset under the Investment Company Act of 1940, as amended, or the 1940 Act. A business development company may not acquire any asset other than a qualifying asset, unless, at the time the acquisition is made, qualifying assets represent at least 70% of the business development company’s total assets. As of December 31, 2023, 80.8% of the Company’s total assets represented qualifying assets.[16]Security is non-income producing.[17]Security was on non-accrual status as of March 31, 2024.[18]Under the 1940 Act, the Company generally is deemed to “control” a portfolio company if it owns more than 25% of the portfolio company’s voting securities or it has the power to exercise control over the management or policies of such portfolio company. As of March 31, 2024, the Company held investments in portfolio companies of which it is deemed to be an “affiliated person” of and deemed to “control.” The following table presents certain information with respect to investments in portfolio companies of which the Company was deemed to be an affiliated person and deemed to control as of March 31, 2024: Portfolio Company Fair Value at December 31, 2023 Gross Additions (1) Gross Reductions (2) Net Realized Gain (Loss) Net Change in Unrealized Appreciation (Depreciation) Fair Value at March 31, 2024 Interest Income (3) PIK Income (3) Senior Secured Loans—First Lien Allied Wireline Services, LLC $ 22,200 $ — $ — $ — $ (14,965) $ 7,235 $ — $ — Warren Resources, Inc. 23,823 60 — — — 23,883 881 60 Sustainable Infrastructure Investments, LLC Sustainable Infrastructure Investments, LLC 39,427 — — — 1,403 40,830 — — Equity/Other Allied Wireline Services, LLC, Common Equity — — — — — — — — Allied Wireline Services, LLC, Warrants — — — — — — — — Warren Resources, Inc., Common Equity 15,566 127 — — (1,276) 14,417 — — $ 101,016 $ 187 $ — $ — $ (14,838) $ 86,365 $ 881 $ 60 _____________ (1) Gross additions may include increases in the cost basis of investments resulting from new portfolio investments, PIK interest, the amortization of unearned income, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company into this category from a different category. (2) Gross reductions may include decreases in the cost basis of investments resulting from principal collections related to investment repayments or sales, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company out of this category into a different category. (3) Interest and PIK income presented for the three months ended March 31, 2024. Portfolio Company Fair Value at December 31, 2022 Gross Additions (1) Gross Reductions (2) Net Realized Gain (Loss) Net Change in Unrealized Appreciation (Depreciation) Fair Value at December 31, 2023 Interest Income (3) PIK Income (3) Dividend Income (3) Senior Secured Loans—First Lien Allied Downhole Technologies, LLC $ 8,436 $ 138 $ (8,574) $ — $ — $ — $ 256 $ 139 $ — Allied Wireline Services, LLC 63,888 6,389 — — (48,077) 22,200 — 2,910 — Warren Resources, Inc. 23,584 239 — — — 23,823 3,464 179 — Sustainable Infrastructure Investments, LLC Sustainable Infrastructure Investments, LLC 51,098 — (11,364) — (307) 39,427 — — 8,324 Equity/Other Allied Wireline Services, LLC, Common Equity 10,463 — — — (10,463) — — — — Allied Wireline Services, LLC, Warrants — — — — — — — — — Warren Resources, Inc., Common Equity 36,982 — — — (21,416) 15,566 — — — $ 194,451 $ 6,766 $ (19,938) $ — $ (80,263) $ 101,016 $ 3,720 $ 3,228 $ 8,324 _____________ (1) Gross additions may include increases in the cost basis of investments resulting from new portfolio investments, PIK interest, the amortization of unearned income, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company into this category from a different category. (2) Gross reductions may include decreases in the cost basis of investments resulting from principal collections related to investment repayments or sales, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company out of this category into a different category. (3) Interest, PIK and dividend income presented for the year ended December 31, 2023. Portfolio Company Fair Value at December 31, 2023 Gross Additions (1) Gross Reductions (2) Net Realized Gain (Loss) Net Change in Unrealized Appreciation (Depreciation) Fair Value at March 31, 2024 Interest Income (3) PIK Income (3) Senior Secured Loans—First Lien Permian Production Holdings, LLC $ 4,816 $ 58 $ (828) $ 71 $ (67) $ 4,050 $ 160 $ 23 Asset Based Finance Bridge Street Warehouse CLO IV Ltd. — 20,329 — — — 20,329 — 329 Equity/Other GWP Midstream Holdco, LLC, Common Equity 1,661 — — — 541 2,202 — — Harvest Oil & Gas Corp., Common Equity 271 — — — 73 344 — — Permian Production Holdings, LLC, Common Equity 748 — — — 295 1,043 — — Telpico, LLC, Common Equity — — — — — — — — $ 7,496 $ 20,387 $ (828) $ 71 $ 842 $ 27,968 $ 160 $ 352 _____________ (1) Gross additions may include increases in the cost basis of investments resulting from new portfolio investments, PIK interest, the amortization of unearned income, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company into this category from a different category. (2) Gross reductions may include decreases in the cost basis of investments resulting from principal collections related to investment repayments or sales, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company out of this category into a different category. (3) Interest and PIK income presented for the three months ended March 31, 2024. Portfolio Company Fair Value at December 31, 2022 Gross Additions (1) Gross Reductions (2) Net Realized Gain (Loss) Net Change in Unrealized Appreciation (Depreciation) Fair Value at December 31, 2023 Interest Income (3) PIK Income (3) Senior Secured Loans—First Lien Permian Production Holdings, LLC $ 4,767 $ 231 $ — $ — $ (182) $ 4,816 $ 675 $ 97 Equity/Other GWP Midstream Holdco, LLC, Common Equity 5,044 — (3,112) 3,112 (3,383) 1,661 — — Harvest Oil & Gas Corp., Common Equity 810 — (641) — 102 271 — — Limetree Bay Energy, LLC, Class A Units 1,885 246 — (21,704) 19,573 — — — Permian Production Holdings, LLC, Common Equity 11,420 — — — (10,672) 748 — — Ridgeback Resources Inc., Common Equity 41,851 — (35,240) (11,359) 4,748 — — — Telpico, LLC, Common Equity — — — — — — — — $ 65,777 $ 477 $ (38,993) $ (29,951) $ 10,186 $ 7,496 $ 675 $ 97 _____________ (1) Gross additions may include increases in the cost basis of investments resulting from new portfolio investments, PIK interest, the amortization of unearned income, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company into this category from a different category. (2) Gross reductions may include decreases in the cost basis of investments resulting from principal collections related to investment repayments or sales, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company out of this category into a different category. (3) Interest and PIK income presented for the year ended December 31, 2023.

Investment Portfolio - Schedu_2

Investment Portfolio - Schedule of Investment Portfolio, at Fair Value and Percentage (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2024		Dec. 31, 2023
Schedule of Investments [Line Items]
Investments, at fair value	$ 1,801,272	[1],[2]	$ 1,523,196	[3],[4]
All Industries \| Percentage of Portfolio \| Industry Concentration Risk
Schedule of Investments [Line Items]
Percentage of Portfolio	100%		100%
Energy—Midstream
Schedule of Investments [Line Items]
Investments, at fair value	$ 354,759		$ 303,175
Energy—Midstream \| Percentage of Portfolio \| Industry Concentration Risk
Schedule of Investments [Line Items]
Percentage of Portfolio	20%		20%
Energy—Upstream
Schedule of Investments [Line Items]
Investments, at fair value	$ 214,120		$ 309,456
Energy—Upstream \| Percentage of Portfolio \| Industry Concentration Risk
Schedule of Investments [Line Items]
Percentage of Portfolio	12%		20%
Consumer Services
Schedule of Investments [Line Items]
Investments, at fair value	$ 190,829		$ 156,089
Consumer Services \| Percentage of Portfolio \| Industry Concentration Risk
Schedule of Investments [Line Items]
Percentage of Portfolio	11%		10%
Capital Goods
Schedule of Investments [Line Items]
Investments, at fair value	$ 140,295		$ 116,454
Capital Goods \| Percentage of Portfolio \| Industry Concentration Risk
Schedule of Investments [Line Items]
Percentage of Portfolio	8%		8%
U.S. Treasury
Schedule of Investments [Line Items]
Investments, at fair value	$ 126,825		$ 21,000
U.S. Treasury \| Percentage of Portfolio \| Industry Concentration Risk
Schedule of Investments [Line Items]
Percentage of Portfolio	7%		1%
Commercial & Professional Services
Schedule of Investments [Line Items]
Investments, at fair value	$ 100,700		$ 62,036
Commercial & Professional Services \| Percentage of Portfolio \| Industry Concentration Risk
Schedule of Investments [Line Items]
Percentage of Portfolio	6%		4%
Financial Services
Schedule of Investments [Line Items]
Investments, at fair value	$ 90,663		$ 83,197
Financial Services \| Percentage of Portfolio \| Industry Concentration Risk
Schedule of Investments [Line Items]
Percentage of Portfolio	5%		6%
Health Care Equipment & Services
Schedule of Investments [Line Items]
Investments, at fair value	$ 90,338		$ 73,105
Health Care Equipment & Services \| Percentage of Portfolio \| Industry Concentration Risk
Schedule of Investments [Line Items]
Percentage of Portfolio	5%		5%
Consumer Discretionary Distribution & Retail
Schedule of Investments [Line Items]
Investments, at fair value	$ 67,022		$ 37,428
Consumer Discretionary Distribution & Retail \| Percentage of Portfolio \| Industry Concentration Risk
Schedule of Investments [Line Items]
Percentage of Portfolio	4%		3%
Energy—Power
Schedule of Investments [Line Items]
Investments, at fair value	$ 58,581		$ 69,696
Energy—Power \| Percentage of Portfolio \| Industry Concentration Risk
Schedule of Investments [Line Items]
Percentage of Portfolio	3%		5%
Materials
Schedule of Investments [Line Items]
Investments, at fair value	$ 55,906		$ 49,653
Materials \| Percentage of Portfolio \| Industry Concentration Risk
Schedule of Investments [Line Items]
Percentage of Portfolio	3%		3%
Automobiles & Components
Schedule of Investments [Line Items]
Investments, at fair value	$ 49,639		$ 39,521
Automobiles & Components \| Percentage of Portfolio \| Industry Concentration Risk
Schedule of Investments [Line Items]
Percentage of Portfolio	3%		3%
Transportation
Schedule of Investments [Line Items]
Investments, at fair value	$ 42,092		$ 30,157
Transportation \| Percentage of Portfolio \| Industry Concentration Risk
Schedule of Investments [Line Items]
Percentage of Portfolio	2%		2%
Household & Personal Products
Schedule of Investments [Line Items]
Investments, at fair value	$ 26,081		$ 20,858
Household & Personal Products \| Percentage of Portfolio \| Industry Concentration Risk
Schedule of Investments [Line Items]
Percentage of Portfolio	1%		1%
Insurance
Schedule of Investments [Line Items]
Investments, at fair value	$ 25,269		$ 20,251
Insurance \| Percentage of Portfolio \| Industry Concentration Risk
Schedule of Investments [Line Items]
Percentage of Portfolio	1%		1%
Consumer Durables & Apparel
Schedule of Investments [Line Items]
Investments, at fair value	$ 24,404		$ 0
Consumer Durables & Apparel \| Percentage of Portfolio \| Industry Concentration Risk
Schedule of Investments [Line Items]
Percentage of Portfolio	1%		0%
Consumer Staples Distribution & Retail
Schedule of Investments [Line Items]
Investments, at fair value	$ 24,337		$ 18,830
Consumer Staples Distribution & Retail \| Percentage of Portfolio \| Industry Concentration Risk
Schedule of Investments [Line Items]
Percentage of Portfolio	1%		1%
Telecommunication Services
Schedule of Investments [Line Items]
Investments, at fair value	$ 19,400		$ 0
Telecommunication Services \| Percentage of Portfolio \| Industry Concentration Risk
Schedule of Investments [Line Items]
Percentage of Portfolio	1%		0%
Pharmaceuticals, Biotechnology & Life Sciences
Schedule of Investments [Line Items]
Investments, at fair value	$ 19,352		$ 19,300
Pharmaceuticals, Biotechnology & Life Sciences \| Percentage of Portfolio \| Industry Concentration Risk
Schedule of Investments [Line Items]
Percentage of Portfolio	1%		1%
Technology Hardware & Equipment
Schedule of Investments [Line Items]
Investments, at fair value	$ 13,685		$ 0
Technology Hardware & Equipment \| Percentage of Portfolio \| Industry Concentration Risk
Schedule of Investments [Line Items]
Percentage of Portfolio	1%		0%
Energy—Service & Equipment
Schedule of Investments [Line Items]
Investments, at fair value	$ 13,629		$ 33,734
Energy—Service & Equipment \| Percentage of Portfolio \| Industry Concentration Risk
Schedule of Investments [Line Items]
Percentage of Portfolio	1%		2%
Media & Entertainment
Schedule of Investments [Line Items]
Investments, at fair value	$ 12,516		$ 19,829
Media & Entertainment \| Percentage of Portfolio \| Industry Concentration Risk
Schedule of Investments [Line Items]
Percentage of Portfolio	1%		1%
Sustainable Infrastructure Investments, LLC
Schedule of Investments [Line Items]
Investments, at fair value	$ 40,830		$ 39,427
Sustainable Infrastructure Investments, LLC \| Percentage of Portfolio \| Industry Concentration Risk
Schedule of Investments [Line Items]
Percentage of Portfolio	2%		3%

[1]Security may be an obligation of one or more entities affiliated with the named company.[2]See Note 8 for additional information regarding the fair value of the Company’s financial instruments.[3]Security may be an obligation of one or more entities affiliated with the named company.[4]See Note 8 for additional information regarding the fair value of the Company’s financial instruments.

Investment Portfolio - Individu

Investment Portfolio - Individual Loans in SIIJV’s portfolio (Details) $ in Thousands		Mar. 31, 2024 USD ($) portfolio_asset		Dec. 31, 2023 USD ($) portfolio_asset		Jan. 02, 2020 USD ($)
Investment, Identifier [Axis]: AI Aqua Merger Sub, Inc., Capital Goods 1
Schedule of Investments [Line Items]
Principal  Amount		$ 17,948	[1],[2]	$ 16,522	[3],[4],[5]
Investment, Identifier [Axis]: AI Aqua Merger Sub, Inc., Capital Goods 2
Schedule of Investments [Line Items]
Principal  Amount		2,052	[1],[6]	3,478	[3],[5],[7]
Investment, Identifier [Axis]: AIRRO (Mauritius) Holdings II, Energy—Power
Schedule of Investments [Line Items]
Principal  Amount		14,865	[1],[8],[9],[10]	22,856	[3],[11],[12],[13]
Investment, Identifier [Axis]: Acrisure, LLC, Insurance
Schedule of Investments [Line Items]
Principal  Amount		25,112	[1],[2]	20,175	[3],[4]
Investment, Identifier [Axis]: Aimbridge Acquisition Co. Inc., Consumer Services
Schedule of Investments [Line Items]
Principal  Amount		26,735	[1],[2]	21,805	[3],[4]
Investment, Identifier [Axis]: Allegiant Travel Co., Transportation
Schedule of Investments [Line Items]
Principal  Amount		$ 10,601	[1],[10]	$ 10,601	[3],[13]
Weighted average current interest rate on debt investments		7.30%	[10],[14]	7.30%	[13],[15]
Investment, Identifier [Axis]: Allied Universal Holdco LLC, Consumer Services 1
Schedule of Investments [Line Items]
Principal  Amount		$ 14,420	[1],[2]	$ 9,975	[3],[4]
Investment, Identifier [Axis]: Allied Universal Holdco LLC, Consumer Services 2
Schedule of Investments [Line Items]
Principal  Amount		9,904	[1],[2]	9,929	[3],[4]
Investment, Identifier [Axis]: Allied Wireline Services, LLC, Energy—Service & Equipment
Schedule of Investments [Line Items]
Principal  Amount		$ 70,277	[1],[8],[16],[17],[18]	$ 70,277	[3],[11],[19],[20],[21]
Investment, Identifier [Axis]: Allspring Government Money Market Fund - Select Class, Money Market Fund
Schedule of Investments [Line Items]
Weighted average current interest rate on debt investments		5.20%		5.30%
Investment, Identifier [Axis]: American Auto Auction Group, LLC, Capital Goods
Schedule of Investments [Line Items]
Principal  Amount		$ 23,913	[1],[2],[22]	$ 9,975	[3],[4]
Investment, Identifier [Axis]: Aretec Escrow Issuer Inc., Financial Services
Schedule of Investments [Line Items]
Principal  Amount		$ 7,000	[1],[2]	$ 7,000	[3],[4]
Weighted average current interest rate on debt investments		10%	[2],[14]	10%	[4],[15]
Investment, Identifier [Axis]: Aretec Group, Inc., Financial Services
Schedule of Investments [Line Items]
Principal  Amount		$ 6,834	[1],[2],[22]	$ 9,352	[3],[4],[5]
Investment, Identifier [Axis]: Auris Luxembourg III S.a r.l, Health Care Equipment & Services
Schedule of Investments [Line Items]
Principal  Amount		20,234	[1],[2],[10]	20,287	[3],[4],[13]
Investment, Identifier [Axis]: Aveanna Healthcare LLC, Health Care Equipment & Services
Schedule of Investments [Line Items]
Principal  Amount		20,855	[1],[2]	15,909	[3],[4]
Investment, Identifier [Axis]: BCPE Empire Holdings, Inc., Consumer Services
Schedule of Investments [Line Items]
Principal  Amount		22,400	[1],[2],[22]	24,900	[3],[4]
Investment, Identifier [Axis]: Bridge Street Warehouse CLO IV Ltd., Financial Services
Schedule of Investments [Line Items]
Principal  Amount	[1],[8],[10],[23],[24]	$ 20,000
Weighted average current interest rate on debt investments	[8],[10],[14],[23],[24]	1.60%
Investment, Identifier [Axis]: CCS-CMGC Holdings, Inc., Health Care Equipment & Services
Schedule of Investments [Line Items]
Principal  Amount		$ 27,768	[1],[2]	21,465	[3],[4]
Investment, Identifier [Axis]: CPM Holdings, Inc., Capital Goods
Schedule of Investments [Line Items]
Principal  Amount		24,938	[1],[2]	20,000	[3],[4]
Investment, Identifier [Axis]: CT Technologies Intermediate Holdings, Inc., Health Care Equipment & Services
Schedule of Investments [Line Items]
Principal  Amount	[1],[2]	9,974
Investment, Identifier [Axis]: Charlotte Buyer, Inc., Health Care Equipment & Services
Schedule of Investments [Line Items]
Principal  Amount		17,800	[1],[2]	19,845	[3],[4],[5]
Investment, Identifier [Axis]: CircusTrix Holdings, LLC, Consumer Services 1
Schedule of Investments [Line Items]
Principal  Amount		20,863	[1],[2],[8]	20,915	[3],[4],[11]
Investment, Identifier [Axis]: CircusTrix Holdings, LLC, Consumer Services 2
Schedule of Investments [Line Items]
Principal  Amount		2,688	[1],[6],[8]	2,688	[3],[7],[11]
Investment, Identifier [Axis]: CircusTrix Holdings, LLC, Consumer Services 3
Schedule of Investments [Line Items]
Principal  Amount		1,344	[1],[6],[8]	1,344	[3],[7],[11]
Investment, Identifier [Axis]: Cirque Du Soleil Holding USA Newco, Inc., Financial Services
Schedule of Investments [Line Items]
Principal  Amount		8,365	[1],[2]	6,387	[3],[4],[5]
Investment, Identifier [Axis]: Citizen Energy Operating, LLC, Energy—Upstream
Schedule of Investments [Line Items]
Principal  Amount		34,000	[1],[2],[8]	35,000	[3],[4],[11]
Investment, Identifier [Axis]: Clear Channel Outdoor Holdings, Inc., Media & Entertainment
Schedule of Investments [Line Items]
Principal  Amount		12,500	[1],[2],[10]	20,000	[3],[4],[13]
Investment, Identifier [Axis]: Clydesdale Acquisition Holdings Inc., Financial Services
Schedule of Investments [Line Items]
Principal  Amount	[1],[2]	17,405
Investment, Identifier [Axis]: Clydesdale Acquisition Holdings Inc., Financials Services
Schedule of Investments [Line Items]
Principal  Amount	[3],[4]			19,949
Investment, Identifier [Axis]: Cox Oil Offshore, LLC, Volumetric Production Payments, Energy—Upstream
Schedule of Investments [Line Items]
Principal  Amount	[3],[11],[25],[26]			$ 100,000
Weighted average current interest rate on debt investments	[11],[15],[25],[26]			12.90%
Investment, Identifier [Axis]: Crown SubSea Communication Holding, Inc., Capital Goods
Schedule of Investments [Line Items]
Principal  Amount	[1],[2]	6,000
Investment, Identifier [Axis]: Crown SubSea Communications Holding, Inc., Capital Goods 1
Schedule of Investments [Line Items]
Principal  Amount	[3],[4],[5]			$ 4,500
Investment, Identifier [Axis]: Crown SubSea Communications Holding, Inc., Capital Goods 2
Schedule of Investments [Line Items]
Principal  Amount	[3],[4],[5]			5,430
Investment, Identifier [Axis]: Delivery Hero Finco LLC, Consumer Services
Schedule of Investments [Line Items]
Principal  Amount	[1],[10],[22]	20,000
Investment, Identifier [Axis]: Digicel International Finance Ltd., Telecommunication Services
Schedule of Investments [Line Items]
Principal  Amount	[1],[2]	20,000
Investment, Identifier [Axis]: Engineered Machinery Holdings, Inc., Capital Goods
Schedule of Investments [Line Items]
Principal  Amount		24,860	[1],[2]	19,924	[3],[4]
Investment, Identifier [Axis]: FR XIII PAA Holdings HoldCo, LLC, Energy—Midstream
Schedule of Investments [Line Items]
Principal  Amount	[3],[4],[11]			17,047
Investment, Identifier [Axis]: First Brands Group, LLC, Automobiles & Components
Schedule of Investments [Line Items]
Principal  Amount		24,841	[1],[2]	19,905	[3],[4]
Investment, Identifier [Axis]: Full House Resorts, Inc., Consumer Services
Schedule of Investments [Line Items]
Principal  Amount		$ 25,742	[1],[2]	$ 20,742	[3],[4]
Weighted average current interest rate on debt investments		8.30%	[2],[14]	8.30%	[4],[15]
Investment, Identifier [Axis]: GasLog Ltd., Energy—Midstream
Schedule of Investments [Line Items]
Principal  Amount		$ 13,951	[1],[8],[10]	$ 13,951	[3],[11],[13]
Weighted average current interest rate on debt investments	[11],[13],[15]			7.80%
Investment, Identifier [Axis]: Global Jet Capital Holdings, LP, Preferred Equity, Commercial & Professional Services 2
Schedule of Investments [Line Items]
Weighted average current interest rate on debt investments	[8],[14],[16],[17],[27]	9%
Investment, Identifier [Axis]: Global Tel Link Corp., Technology Hardware & Equipment
Schedule of Investments [Line Items]
Principal  Amount	[1],[2],[22]	$ 14,031
Investment, Identifier [Axis]: Gold Rush Amusements, Inc., Consumer Services
Schedule of Investments [Line Items]
Principal  Amount		30,596	[1],[2],[8]	$ 30,673	[3],[4],[11]
Investment, Identifier [Axis]: Goodnight Water Solutions, LLC, Energy—Midstream
Schedule of Investments [Line Items]
Principal  Amount		14,328	[1],[2],[8]	14,516	[3],[4],[11]
Investment, Identifier [Axis]: Guardian US Holdco, LLC, Financial Services
Schedule of Investments [Line Items]
Principal  Amount		24,863	[1],[2]	19,925	[3],[4]
Investment, Identifier [Axis]: Guitar Center, Inc., Consumer Discretionary Distribution & Retail
Schedule of Investments [Line Items]
Principal  Amount		$ 23,568	[1],[2]	$ 20,000	[3],[4]
Weighted average current interest rate on debt investments		8.50%	[2],[14]	8.50%	[4],[15]
Investment, Identifier [Axis]: Knowlton Development Corporation Inc., Household & Personal Products
Schedule of Investments [Line Items]
Principal  Amount		$ 26,000	[1],[2]	$ 21,000	[3],[4]
Investment, Identifier [Axis]: LABL, Inc., Commercial & Professional Services
Schedule of Investments [Line Items]
Principal  Amount	[1],[2]	24,801
Investment, Identifier [Axis]: LABL, Inc., Commerical & Professional Services
Schedule of Investments [Line Items]
Principal  Amount	[3],[4]			19,864
Investment, Identifier [Axis]: LaserShip, Inc., Transportation
Schedule of Investments [Line Items]
Principal  Amount	[1],[2]	6,982
Investment, Identifier [Axis]: Learning Care Group No. 2 Inc., Consumer Services
Schedule of Investments [Line Items]
Principal  Amount		21,895	[1],[2]	19,950	[3],[4]
Investment, Identifier [Axis]: MBS Services Holdings, LLC, Commercial & Professional Services
Schedule of Investments [Line Items]
Principal  Amount	[1],[8]	$ 28,622
Weighted average current interest rate on debt investments	[8],[14]	15%
Investment, Identifier [Axis]: Mavis Tire Express Services TopCo, L.P., Consumer Discretionary Distribution & Retail
Schedule of Investments [Line Items]
Principal  Amount		$ 17,349	[1],[2]	$ 19,893	[3],[4]
Investment, Identifier [Axis]: NGL Energy Partners, LP, Preferred Equity, Energy—Midstream
Schedule of Investments [Line Items]
Weighted average current interest rate on debt investments		14.20%	[2],[8],[10],[14],[17],[27]	14.20%	[4],[11],[13],[15],[19],[20]
Investment, Identifier [Axis]: Navios Logistics Finance, Inc., Transportation
Schedule of Investments [Line Items]
Principal  Amount		$ 25,000	[1],[2],[10]	$ 20,000	[3],[4],[13]
Weighted average current interest rate on debt investments		10.80%	[2],[10],[14]	10.80%	[4],[13],[15]
Investment, Identifier [Axis]: Nephron Pharmaceuticals Corp., Pharmaceuticals, Biotechnology & Life Sciences
Schedule of Investments [Line Items]
Principal  Amount		$ 19,925	[1],[8]	$ 20,000	[3],[11]
Investment, Identifier [Axis]: Osaic Holdings, Inc., Financial Services
Schedule of Investments [Line Items]
Principal  Amount	[1],[2],[22]	4,988
Investment, Identifier [Axis]: Permian Production Holdings, LLC, Energy—Upstream
Schedule of Investments [Line Items]
Principal  Amount		$ 4,060	[1],[8],[24]	$ 4,864	[3],[11],[28]
Weighted average current interest rate on debt investments		7%	[8],[14],[24]	7%	[11],[15],[28]
Investment, Identifier [Axis]: Phoenix Guarantor Inc., Financial Services
Schedule of Investments [Line Items]
Principal  Amount	[3],[4],[5]			$ 19,923
Investment, Identifier [Axis]: Plainfield Renewable Energy Holdings LLC, Energy—Power 2
Schedule of Investments [Line Items]
Principal  Amount	[1],[8],[16],[17]	$ 4,218
Investment, Identifier [Axis]: Plainfield Renewable Energy Holdings LLC, Energy—Power 1
Schedule of Investments [Line Items]
Principal  Amount		$ 13,936	[1],[8],[16],[17]	$ 13,297	[3],[11],[19],[20]
Weighted average current interest rate on debt investments		6%	[8],[14],[16],[17]	6%	[11],[15],[19],[20]
Investment, Identifier [Axis]: Plainfield Renewable Energy Holdings LLC, Energy—Power 2
Schedule of Investments [Line Items]
Principal  Amount	[3],[11],[19],[20]			$ 4,015
Investment, Identifier [Axis]: Plainfield Renewable Energy Holdings LLC, Letter of Credit, Energy—Power
Schedule of Investments [Line Items]
Principal  Amount		$ 2,709	[1],[6],[8]	$ 2,709	[3],[7],[11]
Weighted average current interest rate on debt investments		10%	[6],[8],[14]	10%	[7],[11],[15]
Investment, Identifier [Axis]: Pretium PKG Holdings, Inc., Materials
Schedule of Investments [Line Items]
Principal  Amount		$ 32,378	[1],[2]	$ 30,118	[3],[4]
Investment, Identifier [Axis]: Pro Mach Group, Inc., Capital Goods
Schedule of Investments [Line Items]
Principal  Amount		17,424	[1],[2]	19,924	[3],[4]
Investment, Identifier [Axis]: Proampac PG Borrower LLC, Materials
Schedule of Investments [Line Items]
Principal  Amount		22,942	[1],[2]	20,000	[3],[4]
Investment, Identifier [Axis]: RealTruck Group, Inc., Automobiles & Components
Schedule of Investments [Line Items]
Principal  Amount	[1],[2]	24,885
Investment, Identifier [Axis]: Realtruck Group, Inc., Automobiles & Components
Schedule of Investments [Line Items]
Principal  Amount	[3],[4],[5]			19,956
Investment, Identifier [Axis]: Ryan, LLC, Commercial & Professional Services 1
Schedule of Investments [Line Items]
Principal  Amount	[1],[2]	9,844
Investment, Identifier [Axis]: Ryan, LLC, Commercial & Professional Services 2
Schedule of Investments [Line Items]
Principal  Amount	[1],[6]	1,036
Investment, Identifier [Axis]: Ryan, LLC, Commerical & Professional Services 1
Schedule of Investments [Line Items]
Principal  Amount	[3],[4],[5]			9,844
Investment, Identifier [Axis]: Ryan, LLC, Commerical & Professional Services 2
Schedule of Investments [Line Items]
Principal  Amount	[3],[5],[7]			1,036
Investment, Identifier [Axis]: SRS Distribution Inc., Capital Goods
Schedule of Investments [Line Items]
Principal  Amount		24,860	[1],[2]	19,924	[3],[4],[5]
Investment, Identifier [Axis]: ST EIP Holdings Inc., Energy—Midstream
Schedule of Investments [Line Items]
Principal  Amount		$ 10,311	[1],[2],[8]	$ 10,365	[3],[4],[11]
Weighted average current interest rate on debt investments		6.30%	[2],[8],[14]	6.30%	[4],[11],[15]
Investment, Identifier [Axis]: Sustainable Infrastructure Investments, LLC, Energy—Power
Schedule of Investments [Line Items]
Principal  Amount		$ 60,603	[1],[8],[10],[18]	$ 60,603	[11],[13],[21]
Investment, Identifier [Axis]: TKC Holdings, Inc., Consumer Staples Distribution & Retail
Schedule of Investments [Line Items]
Principal  Amount		24,536	[1],[2]	19,650	[3],[4]
Investment, Identifier [Axis]: Tenrgys, LLC, Energy—Upstream
Schedule of Investments [Line Items]
Principal  Amount		20,537	[1],[2],[8]	20,537	[3],[4],[11]
Investment, Identifier [Axis]: TruGreen, LP, Commercial & Professional Services
Schedule of Investments [Line Items]
Principal  Amount		24,846	[1],[2]	19,910	[3],[4]
Investment, Identifier [Axis]: U.S. Treasury Bills, U.S. Treasury 1
Schedule of Investments [Line Items]
Principal  Amount	[29],[30]	100,000
Investment, Identifier [Axis]: U.S. Treasury Bills, U.S. Treasury 2
Schedule of Investments [Line Items]
Principal  Amount	[29],[30]	$ 27,000
Investment, Identifier [Axis]: U.S. Treasury Bills, U.S. Treasury Bills
Schedule of Investments [Line Items]
Principal  Amount	[31]			$ 21,000
Investment, Identifier [Axis]: USA Compression Partners, LP, Preferred Equity, Energy—Midstream
Schedule of Investments [Line Items]
Weighted average current interest rate on debt investments		9.80%	[2],[8],[10],[14],[27]	9.80%	[4],[11],[13],[15]
Investment, Identifier [Axis]: WMK, LLC, Consumer Discretionary Distribution & Retail 1
Schedule of Investments [Line Items]
Principal  Amount	[1],[2],[8]	$ 29,833
Investment, Identifier [Axis]: WMK, LLC, Consumer Discretionary Distribution & Retail 2
Schedule of Investments [Line Items]
Principal  Amount	[1],[6],[8]	5,167
Investment, Identifier [Axis]: Warren Resources, Inc., Energy—Upstream
Schedule of Investments [Line Items]
Principal  Amount		23,883	[1],[2],[8],[18]	$ 23,823	[3],[4],[11],[21]
Investment, Identifier [Axis]: Wattbridge Inc., Energy—Power
Schedule of Investments [Line Items]
Principal  Amount		42,938	[1],[2],[8]	42,938	[3],[4],[11]
Investment, Identifier [Axis]: Weber-Stephen Products LLC, Consumer Durables & Apparel
Schedule of Investments [Line Items]
Principal  Amount	[1],[2],[22]	26,285
Sustainable Infrastructure Investments, LLC
Schedule of Investments [Line Items]
Principal  Amount		$ 153,837		$ 170,083
Number of portfolio assets in SIIJV \| portfolio_asset		5		6
Sustainable Infrastructure Investments, LLC \| Investment, Identifier [Axis]: Blue Heron Intermediate Holdco I, LLC, Midstream
Schedule of Investments [Line Items]
Principal  Amount		$ 30,343		$ 30,661
Sustainable Infrastructure Investments, LLC \| Investment, Identifier [Axis]: Copper Mountain Solar 3, LLC, Renewables
Schedule of Investments [Line Items]
Principal  Amount		16,104		16,104
Sustainable Infrastructure Investments, LLC \| Investment, Identifier [Axis]: FLNG Liquefaction 2, LLC, Midstream
Schedule of Investments [Line Items]
Principal  Amount		26,164		26,567
Sustainable Infrastructure Investments, LLC \| Investment, Identifier [Axis]: Largest Portfolio Company Investment
Schedule of Investments [Line Items]
Principal  Amount		57,227		57,227
Sustainable Infrastructure Investments, LLC \| Investment, Identifier [Axis]: NES Hercules Class B Member, LLC, Renewables
Schedule of Investments [Line Items]
Principal  Amount		23,999		24,176
Sustainable Infrastructure Investments, LLC \| Investment, Identifier [Axis]: ST EIP Holdco LLC, Midstream
Schedule of Investments [Line Items]
Principal  Amount		$ 57,227		57,227
Sustainable Infrastructure Investments, LLC \| Investment, Identifier [Axis]: Seine Funding, LLC
Schedule of Investments [Line Items]
Principal  Amount						$ 634,103
Sustainable Infrastructure Investments, LLC \| Investment, Identifier [Axis]: Top of the World Wind Energy LLC, Renewables
Schedule of Investments [Line Items]
Principal  Amount				$ 15,348
Sustainable Infrastructure Investments, LLC \| Weighted Average
Schedule of Investments [Line Items]
Weighted average current interest rate on debt investments		7.41%		7.45%

[1]Denominated in U.S. dollars, unless otherwise noted.[2]Security or portion thereof held within FSSL Finance BB AssetCo LLC, a wholly-owned subsidiary of the Company, and is pledged as collateral supporting the obligations outstanding under the repurchase facility with Barclays Bank PLC (see Note 9).[3]Denominated in U.S. dollars, unless otherwise noted.[4]Security or portion thereof held within FSSL Finance BB AssetCo LLC, a wholly-owned subsidiary of the Company, and is pledged as collateral supporting the obligations outstanding under the repurchase facility with Barclays Bank PLC (see Note 9).[5]Security or portion thereof unsettled as of December 31, 2023.[6]Security is an unfunded commitment. The stated rate reflects the spread disclosed at the time of commitment and may not indicate the actual rate received upon funding.[7]Security is an unfunded commitment. The stated rate reflects the spread disclosed at the time of commitment and may not indicate the actual rate received upon funding.[8]Security is classified as Level 3 in the Company’s fair value hierarchy (see Note 8).[9]Security or portion thereof held within FS Power Investments II, LLC, a wholly-owned subsidiary of the Company.[10]The investment is not a qualifying asset under the Investment Company Act of 1940, as amended, or the 1940 Act. A business development company may not acquire any asset other than a qualifying asset, unless, at the time the acquisition is made, qualifying assets represent at least 70% of the business development company’s total assets. As of March 31, 2024, 75.7% of the Company’s total assets represented qualifying assets.[11]Security is classified as Level 3 in the Company’s fair value hierarchy (see Note 8).[12]Security or portion thereof held within FS Power Investments II, LLC, a wholly-owned subsidiary of the Company.[13]The investment is not a qualifying asset under the Investment Company Act of 1940, as amended, or the 1940 Act. A business development company may not acquire any asset other than a qualifying asset, unless, at the time the acquisition is made, qualifying assets represent at least 70% of the business development company’s total assets. As of December 31, 2023, 80.8% of the Company’s total assets represented qualifying assets.[14]Certain variable rate securities in the Company’s portfolio bear interest at a rate determined by a publicly disclosed base rate plus a basis point spread. As of March 31, 2024, the one-month and three-month Secured Overnight Financing Rate, or SOFR, or S, was 5.33% and 5.30%, respectively, and the Overnight Bank Funding Rate, or OBFR, was 5.33%. SOFR based contracts may include a credit spread adjustment that is charged in addition to the base rate and basis point spread. PIK means paid-in-kind. PIK income accruals may be adjusted based on the fair value of the underlying investment. Variable rate securities with no floor rate use the respective benchmark rate in all cases.[15]Certain variable rate securities in the Company’s portfolio bear interest at a rate determined by a publicly disclosed base rate plus a basis point spread. As of December 31, 2023, the one-month and three-month Secured Overnight Financing Rate, or SOFR, or S, was 5.35% and 5.33%, respectively, and the Overnight Bank Funding Rate, or OBFR, was 5.32%. SOFR based contracts may include a credit spread adjustment that is charged in addition to the base rate and basis point spread. PIK means paid-in-kind. PIK income accruals may be adjusted based on the fair value of the underlying investment. Variable rate securities with no floor rate use the respective benchmark rate in all cases.[16]Security is non-income producing.[17]Security was on non-accrual status as of March 31, 2024.[18]Under the 1940 Act, the Company generally is deemed to “control” a portfolio company if it owns more than 25% of the portfolio company’s voting securities or it has the power to exercise control over the management or policies of such portfolio company. As of March 31, 2024, the Company held investments in portfolio companies of which it is deemed to be an “affiliated person” of and deemed to “control.” The following table presents certain information with respect to investments in portfolio companies of which the Company was deemed to be an affiliated person and deemed to control as of March 31, 2024: Portfolio Company Fair Value at December 31, 2023 Gross Additions (1) Gross Reductions (2) Net Realized Gain (Loss) Net Change in Unrealized Appreciation (Depreciation) Fair Value at March 31, 2024 Interest Income (3) PIK Income (3) Senior Secured Loans—First Lien Allied Wireline Services, LLC $ 22,200 $ — $ — $ — $ (14,965) $ 7,235 $ — $ — Warren Resources, Inc. 23,823 60 — — — 23,883 881 60 Sustainable Infrastructure Investments, LLC Sustainable Infrastructure Investments, LLC 39,427 — — — 1,403 40,830 — — Equity/Other Allied Wireline Services, LLC, Common Equity — — — — — — — — Allied Wireline Services, LLC, Warrants — — — — — — — — Warren Resources, Inc., Common Equity 15,566 127 — — (1,276) 14,417 — — $ 101,016 $ 187 $ — $ — $ (14,838) $ 86,365 $ 881 $ 60 _____________ (1) Gross additions may include increases in the cost basis of investments resulting from new portfolio investments, PIK interest, the amortization of unearned income, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company into this category from a different category. (2) Gross reductions may include decreases in the cost basis of investments resulting from principal collections related to investment repayments or sales, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company out of this category into a different category. (3) Interest and PIK income presented for the three months ended March 31, 2024. Portfolio Company Fair Value at December 31, 2022 Gross Additions (1) Gross Reductions (2) Net Realized Gain (Loss) Net Change in Unrealized Appreciation (Depreciation) Fair Value at December 31, 2023 Interest Income (3) PIK Income (3) Dividend Income (3) Senior Secured Loans—First Lien Allied Downhole Technologies, LLC $ 8,436 $ 138 $ (8,574) $ — $ — $ — $ 256 $ 139 $ — Allied Wireline Services, LLC 63,888 6,389 — — (48,077) 22,200 — 2,910 — Warren Resources, Inc. 23,584 239 — — — 23,823 3,464 179 — Sustainable Infrastructure Investments, LLC Sustainable Infrastructure Investments, LLC 51,098 — (11,364) — (307) 39,427 — — 8,324 Equity/Other Allied Wireline Services, LLC, Common Equity 10,463 — — — (10,463) — — — — Allied Wireline Services, LLC, Warrants — — — — — — — — — Warren Resources, Inc., Common Equity 36,982 — — — (21,416) 15,566 — — — $ 194,451 $ 6,766 $ (19,938) $ — $ (80,263) $ 101,016 $ 3,720 $ 3,228 $ 8,324 _____________ (1) Gross additions may include increases in the cost basis of investments resulting from new portfolio investments, PIK interest, the amortization of unearned income, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company into this category from a different category. (2) Gross reductions may include decreases in the cost basis of investments resulting from principal collections related to investment repayments or sales, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company out of this category into a different category. (3) Interest, PIK and dividend income presented for the year ended December 31, 2023. Portfolio Company Fair Value at December 31, 2023 Gross Additions (1) Gross Reductions (2) Net Realized Gain (Loss) Net Change in Unrealized Appreciation (Depreciation) Fair Value at March 31, 2024 Interest Income (3) PIK Income (3) Senior Secured Loans—First Lien Permian Production Holdings, LLC $ 4,816 $ 58 $ (828) $ 71 $ (67) $ 4,050 $ 160 $ 23 Asset Based Finance Bridge Street Warehouse CLO IV Ltd. — 20,329 — — — 20,329 — 329 Equity/Other GWP Midstream Holdco, LLC, Common Equity 1,661 — — — 541 2,202 — — Harvest Oil & Gas Corp., Common Equity 271 — — — 73 344 — — Permian Production Holdings, LLC, Common Equity 748 — — — 295 1,043 — — Telpico, LLC, Common Equity — — — — — — — — $ 7,496 $ 20,387 $ (828) $ 71 $ 842 $ 27,968 $ 160 $ 352 _____________ (1) Gross additions may include increases in the cost basis of investments resulting from new portfolio investments, PIK interest, the amortization of unearned income, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company into this category from a different category. (2) Gross reductions may include decreases in the cost basis of investments resulting from principal collections related to investment repayments or sales, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company out of this category into a different category. (3) Interest and PIK income presented for the three months ended March 31, 2024. Portfolio Company Fair Value at December 31, 2022 Gross Additions (1) Gross Reductions (2) Net Realized Gain (Loss) Net Change in Unrealized Appreciation (Depreciation) Fair Value at December 31, 2023 Interest Income (3) PIK Income (3) Senior Secured Loans—First Lien Permian Production Holdings, LLC $ 4,767 $ 231 $ — $ — $ (182) $ 4,816 $ 675 $ 97 Equity/Other GWP Midstream Holdco, LLC, Common Equity 5,044 — (3,112) 3,112 (3,383) 1,661 — — Harvest Oil & Gas Corp., Common Equity 810 — (641) — 102 271 — — Limetree Bay Energy, LLC, Class A Units 1,885 246 — (21,704) 19,573 — — — Permian Production Holdings, LLC, Common Equity 11,420 — — — (10,672) 748 — — Ridgeback Resources Inc., Common Equity 41,851 — (35,240) (11,359) 4,748 — — — Telpico, LLC, Common Equity — — — — — — — — $ 65,777 $ 477 $ (38,993) $ (29,951) $ 10,186 $ 7,496 $ 675 $ 97 _____________ (1) Gross additions may include increases in the cost basis of investments resulting from new portfolio investments, PIK interest, the amortization of unearned income, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company into this category from a different category. (2) Gross reductions may include decreases in the cost basis of investments resulting from principal collections related to investment repayments or sales, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company out of this category into a different category. (3) Interest and PIK income presented for the year ended December 31, 2023.

Investment Portfolio - Sustaina

Investment Portfolio - Sustainable Infrastructure Investments, LLC Portfolio (Details) - USD ($) $ in Thousands		Mar. 31, 2024		Dec. 31, 2023		Dec. 31, 2022	Jan. 02, 2020
Schedule of Investments [Line Items]
Amortized Cost		$ 1,857,014	[1]	$ 1,543,925	[2]
Investments, at fair value		$ 1,801,272	[1],[3]	$ 1,523,196	[2],[4]
Percent of net assets		114.10%	[1]	97.50%	[2]
Net Senior Secured Loans—First Lien
Schedule of Investments [Line Items]
Amortized Cost		$ 1,031,295	[1]	$ 878,013	[2]
Investments, at fair value		$ 962,663	[1],[3]	$ 825,158	[2],[4]
Percent of net assets		61%	[1]	52.90%	[2]
Investment, Identifier [Axis]: AI Aqua Merger Sub, Inc., Capital Goods 1
Schedule of Investments [Line Items]
Variable rate		4.25%	[5],[6]	4.25%	[7],[8],[9]
Principal  Amount		$ 17,948	[6],[10]	$ 16,522	[8],[9],[11]
Amortized Cost		17,804	[6]	16,398	[8],[9]
Investments, at fair value		$ 18,051	[3],[6]	$ 16,625	[4],[8],[9]
Investment, Identifier [Axis]: AI Aqua Merger Sub, Inc., Capital Goods 2
Schedule of Investments [Line Items]
Variable rate		4.25%	[5],[12]	4.25%	[7],[9],[13]
Principal  Amount		$ 2,052	[10],[12]	$ 3,478	[9],[11],[13]
Amortized Cost		2,052	[12]	3,452	[9],[13]
Investments, at fair value		$ 2,064	[3],[12]	$ 3,500	[4],[9],[13]
Investment, Identifier [Axis]: AIRRO (Mauritius) Holdings II, Energy—Power
Schedule of Investments [Line Items]
Variable rate		4%	[5],[14],[15],[16]	4%	[7],[17],[18],[19]
Principal  Amount		$ 14,865	[10],[14],[15],[16]	$ 22,856	[11],[17],[18],[19]
Amortized Cost		13,405	[14],[15],[16]	20,779	[17],[18],[19]
Investments, at fair value		14,832	[3],[14],[15],[16]	23,050	[4],[17],[18],[19]
Investment, Identifier [Axis]: AIRRO (Mauritius) Holdings II, Warrants, Strike, Energy—Power
Schedule of Investments [Line Items]
Amortized Cost	[14],[15],[16],[20]	2,652
Investments, at fair value	[3],[14],[15],[16],[20]	0
Investment, Identifier [Axis]: AIRRO (Mauritius) Holdings II, Warrants, Strike: $1.00, Energy—Power
Schedule of Investments [Line Items]
Amortized Cost	[17],[18],[19],[21]			2,652
Investments, at fair value	[4],[17],[18],[19],[21]			0
Investment, Identifier [Axis]: Abaco Energy Technologies LLC, Common Equity, Energy—Service & Equipment
Schedule of Investments [Line Items]
Amortized Cost		6,980	[14],[20]	6,944	[17],[21]
Investments, at fair value		685	[3],[14],[20]	1,375	[4],[17],[21]
Investment, Identifier [Axis]: Abaco Energy Technologies LLC, Preferred Equity, Energy—Service & Equipment
Schedule of Investments [Line Items]
Amortized Cost		1,447	[14],[20],[22]	1,447	[17],[21]
Investments, at fair value		$ 5,709	[3],[14],[20],[22]	$ 10,159	[4],[17],[21]
Investment, Identifier [Axis]: Acrisure, LLC, Insurance
Schedule of Investments [Line Items]
Variable rate		4.50%	[5],[6]	4.50%	[7],[8]
Principal  Amount		$ 25,112	[6],[10]	$ 20,175	[8],[11]
Amortized Cost		25,016	[6]	20,033	[8]
Investments, at fair value		$ 25,269	[3],[6]	$ 20,251	[4],[8]
Investment, Identifier [Axis]: Aimbridge Acquisition Co. Inc., Consumer Services
Schedule of Investments [Line Items]
Variable rate		3.75%	[5],[6]	3.75%	[7],[8]
Principal  Amount		$ 26,735	[6],[10]	$ 21,805	[8],[11]
Amortized Cost		25,778	[6]	21,036	[8]
Investments, at fair value		25,921	[3],[6]	20,380	[4],[8]
Investment, Identifier [Axis]: AirSwift Holdings, Ltd., Common Equity, Commercial & Professional Services
Schedule of Investments [Line Items]
Amortized Cost		6,029	[14],[16],[20]	6,029	[17],[19],[21]
Investments, at fair value		3,806	[3],[14],[16],[20]	3,413	[4],[17],[19],[21]
Investment, Identifier [Axis]: Allegiant Travel Co., Transportation
Schedule of Investments [Line Items]
Principal  Amount		10,601	[10],[16]	10,601	[11],[19]
Amortized Cost		9,677	[16]	9,614	[19]
Investments, at fair value		$ 10,556	[3],[16]	10,385	[4],[19]
Investment, Identifier [Axis]: Allied Downhole Technologies, LLC
Schedule of Investments [Line Items]
Investments, at fair value				$ 0		$ 8,436
Investment, Identifier [Axis]: Allied Universal Holdco LLC, Consumer Services 1
Schedule of Investments [Line Items]
Variable rate		4.75%	[5],[6]	4.75%	[7],[8]
Principal  Amount		$ 14,420	[6],[10]	$ 9,975	[8],[11]
Amortized Cost		14,302	[6]	9,841	[8]
Investments, at fair value		$ 14,479	[3],[6]	$ 9,998	[4],[8]
Investment, Identifier [Axis]: Allied Universal Holdco LLC, Consumer Services 2
Schedule of Investments [Line Items]
Variable rate		3.75%	[5],[6]	3.75%	[7],[8]
Principal  Amount		$ 9,904	[6],[10]	$ 9,929	[8],[11]
Amortized Cost		9,615	[6]	9,627	[8]
Investments, at fair value		9,902	[3],[6]	9,903	[4],[8]
Investment, Identifier [Axis]: Allied Wireline Services, LLC
Schedule of Investments [Line Items]
Investments, at fair value		7,235		22,200		63,888
Investment, Identifier [Axis]: Allied Wireline Services, LLC, Common Equity
Schedule of Investments [Line Items]
Investments, at fair value		0		0		10,463
Investment, Identifier [Axis]: Allied Wireline Services, LLC, Common Equity, Energy—Service & Equipment
Schedule of Investments [Line Items]
Amortized Cost		1,527	[14],[20],[23],[24]	1,527	[17],[21],[25],[26]
Investments, at fair value		0	[3],[14],[20],[23],[24]	0	[4],[17],[21],[25],[26]
Investment, Identifier [Axis]: Allied Wireline Services, LLC, Energy—Service & Equipment
Schedule of Investments [Line Items]
Principal  Amount		70,277	[10],[14],[20],[24],[27]	70,277	[11],[17],[21],[26],[28]
Amortized Cost		70,277	[14],[20],[24],[27]	70,277	[17],[21],[26],[28]
Investments, at fair value		7,235	[3],[14],[20],[24],[27]	22,200	[4],[17],[21],[26],[28]
Investment, Identifier [Axis]: Allied Wireline Services, LLC, Warrants
Schedule of Investments [Line Items]
Investments, at fair value		0		0		0
Investment, Identifier [Axis]: Allied Wireline Services, LLC, Warrants, Energy—Service & Equipment
Schedule of Investments [Line Items]
Amortized Cost		0	[14],[20],[23],[24]	0	[17],[21],[25],[26]
Investments, at fair value		0	[3],[14],[20],[23],[24]	0	[4],[17],[21],[25],[26]
Investment, Identifier [Axis]: Allspring Government Money Market Fund - Select Class, Money Market Fund
Schedule of Investments [Line Items]
Investments, at fair value		$ 59,698		$ 23,098
Investment, Identifier [Axis]: American Auto Auction Group, LLC, Capital Goods
Schedule of Investments [Line Items]
Variable rate		5%	[5],[6],[29]	5%	[7],[8]
Principal  Amount		$ 23,913	[6],[10],[29]	$ 9,975	[8],[11]
Amortized Cost		23,634	[6],[29]	9,752	[8]
Investments, at fair value		23,816	[3],[6],[29]	9,858	[4],[8]
Investment, Identifier [Axis]: Arena Energy, LP, Contingent Value Rights, Energy—Upstream
Schedule of Investments [Line Items]
Amortized Cost		351	[14]	351	[17],[21]
Investments, at fair value		351	[3],[14]	571	[4],[17],[21]
Investment, Identifier [Axis]: Aretec Escrow Issuer Inc., Financial Services
Schedule of Investments [Line Items]
Principal  Amount		7,000	[6],[10]	7,000	[8],[11]
Amortized Cost		7,000	[6]	7,000	[8]
Investments, at fair value		$ 7,655	[3],[6]	$ 7,447	[4],[8]
Investment, Identifier [Axis]: Aretec Group, Inc., Financial Services
Schedule of Investments [Line Items]
Variable rate		4.50%	[5],[6],[29]	4.50%	[7],[8],[9]
Principal  Amount		$ 6,834	[6],[10],[29]	$ 9,352	[8],[9],[11]
Amortized Cost		6,804	[6],[29]	9,071	[8],[9]
Investments, at fair value		6,881	[3],[6],[29]	9,358	[4],[8],[9]
Investment, Identifier [Axis]: Ascent Resources Utica Holdings, LLC, Common Equity, Energy—Upstream
Schedule of Investments [Line Items]
Amortized Cost		43,878	[14],[20],[23]	44,573	[17],[21],[25]
Investments, at fair value		$ 36,354	[3],[14],[20],[23]	$ 39,545	[4],[17],[21],[25]
Investment, Identifier [Axis]: Auris Luxembourg III S.a r.l, Health Care Equipment & Services
Schedule of Investments [Line Items]
Variable rate		3.75%	[5],[6],[16]	3.75%	[7],[8],[19]
Principal  Amount		$ 20,234	[6],[10],[16]	$ 20,287	[8],[11],[19]
Amortized Cost		19,897	[6],[16]	19,912	[8],[19]
Investments, at fair value		$ 20,303	[3],[6],[16]	$ 20,079	[4],[8],[19]
Investment, Identifier [Axis]: Aveanna Healthcare LLC, Health Care Equipment & Services
Schedule of Investments [Line Items]
Variable rate		3.75%	[5],[6]	3.75%	[7],[8]
Principal  Amount		$ 20,855	[6],[10]	$ 15,909	[8],[11]
Amortized Cost		18,746	[6]	14,054	[8]
Investments, at fair value		$ 20,106	[3],[6]	$ 14,852	[4],[8]
Investment, Identifier [Axis]: BCPE Empire Holdings, Inc., Consumer Services
Schedule of Investments [Line Items]
Variable rate		4%	[5],[6],[29]	4.75%	[7],[8]
Principal  Amount		$ 22,400	[6],[10],[29]	$ 24,900	[8],[11]
Amortized Cost		22,477	[6],[29]	24,983	[8]
Investments, at fair value		22,450	[3],[6],[29]	24,998	[4],[8]
Investment, Identifier [Axis]: Bridge Street Warehouse CLO IV Ltd., Financial Services
Schedule of Investments [Line Items]
Principal  Amount	[10],[14],[16],[30],[31]	20,000
Amortized Cost	[14],[16],[30],[31]	20,329
Investments, at fair value	[3],[14],[16],[30],[31]	20,329
Investment, Identifier [Axis]: Bridge Street Warehouse CLO IV, Ltd.
Schedule of Investments [Line Items]
Investments, at fair value		$ 20,329		$ 0
Investment, Identifier [Axis]: CCS-CMGC Holdings, Inc., Health Care Equipment & Services
Schedule of Investments [Line Items]
Variable rate		5.50%	[5],[6]	5.50%	[7],[8]
Principal  Amount		$ 27,768	[6],[10]	$ 21,465	[8],[11]
Amortized Cost		24,052	[6]	18,225	[8]
Investments, at fair value		$ 22,081	[3],[6]	$ 18,222	[4],[8]
Investment, Identifier [Axis]: CPM Holdings, Inc., Capital Goods
Schedule of Investments [Line Items]
Variable rate		4.50%	[5],[6]	4.50%	[7],[8]
Principal  Amount		$ 24,938	[6],[10]	$ 20,000	[8],[11]
Amortized Cost		25,010	[6]	20,038	[8]
Investments, at fair value		$ 25,002	[3],[6]	$ 20,092	[4],[8]
Investment, Identifier [Axis]: CT Technologies Intermediate Holdings, Inc., Health Care Equipment & Services
Schedule of Investments [Line Items]
Variable rate	[5],[6]	4.25%
Principal  Amount	[6],[10]	$ 9,974
Amortized Cost	[6]	9,862
Investments, at fair value	[3],[6]	$ 9,968
Investment, Identifier [Axis]: Charlotte Buyer, Inc., Health Care Equipment & Services
Schedule of Investments [Line Items]
Variable rate		5.25%	[5],[6]	5.25%	[7],[8],[9]
Principal  Amount		$ 17,800	[6],[10]	$ 19,845	[8],[9],[11]
Amortized Cost		17,899	[6]	19,937	[8],[9]
Investments, at fair value		$ 17,880	[3],[6]	$ 19,952	[4],[8],[9]
Investment, Identifier [Axis]: CircusTrix Holdings, LLC, Consumer Services 1
Schedule of Investments [Line Items]
Variable rate		6.50%	[5],[6],[14]	6.75%	[7],[8],[17]
Principal  Amount		$ 20,863	[6],[10],[14]	$ 20,915	[8],[11],[17]
Amortized Cost		20,863	[6],[14]	20,915	[8],[17]
Investments, at fair value		$ 21,202	[3],[6],[14]	$ 21,098	[4],[8],[17]
Investment, Identifier [Axis]: CircusTrix Holdings, LLC, Consumer Services 2
Schedule of Investments [Line Items]
Variable rate		6.50%	[5],[12],[14]	6.75%	[7],[13],[17]
Principal  Amount		$ 2,688	[10],[12],[14]	$ 2,688	[11],[13],[17]
Amortized Cost		2,688	[12],[14]	2,688	[13],[17]
Investments, at fair value		$ 2,732	[3],[12],[14]	$ 2,712	[4],[13],[17]
Investment, Identifier [Axis]: CircusTrix Holdings, LLC, Consumer Services 3
Schedule of Investments [Line Items]
Variable rate		6.50%	[5],[12],[14]	6.75%	[7],[13],[17]
Principal  Amount		$ 1,344	[10],[12],[14]	$ 1,344	[11],[13],[17]
Amortized Cost		1,344	[12],[14]	1,344	[13],[17]
Investments, at fair value		$ 1,366	[3],[12],[14]	$ 1,356	[4],[13],[17]
Investment, Identifier [Axis]: Cirque Du Soleil Holding USA Newco, Inc., Financial Services
Schedule of Investments [Line Items]
Variable rate		4.25%	[5],[6]	4.25%	[7],[8],[9]
Principal  Amount		$ 8,365	[6],[10]	$ 6,387	[8],[9],[11]
Amortized Cost		8,317	[6]	6,331	[8],[9]
Investments, at fair value		$ 8,377	[3],[6]	$ 6,372	[4],[8],[9]
Investment, Identifier [Axis]: Citizen Energy Operating, LLC, Energy—Upstream
Schedule of Investments [Line Items]
Variable rate		7.65%	[5],[6],[14]	7.65%	[7],[8],[17]
Principal  Amount		$ 34,000	[6],[10],[14]	$ 35,000	[8],[11],[17]
Amortized Cost		33,540	[6],[14]	34,527	[8],[17]
Investments, at fair value		$ 33,581	[3],[6],[14]	$ 34,426	[4],[8],[17]
Investment, Identifier [Axis]: Clear Channel Outdoor Holdings, Inc., Media & Entertainment
Schedule of Investments [Line Items]
Variable rate		4%	[5],[6],[16]	3.50%	[7],[8],[19]
Principal  Amount		$ 12,500	[6],[10],[16]	$ 20,000	[8],[11],[19]
Amortized Cost		12,258	[6],[16]	19,551	[8],[19]
Investments, at fair value		$ 12,516	[3],[6],[16]	$ 19,829	[4],[8],[19]
Investment, Identifier [Axis]: Clydesdale Acquisition Holdings Inc., Financial Services
Schedule of Investments [Line Items]
Variable rate	[5],[6]	3.75%
Principal  Amount	[6],[10]	$ 17,405
Amortized Cost	[6]	17,312
Investments, at fair value	[3],[6]	$ 17,449
Investment, Identifier [Axis]: Clydesdale Acquisition Holdings Inc., Financials Services
Schedule of Investments [Line Items]
Variable rate	[7],[8]			4.18%
Principal  Amount	[8],[11]			$ 19,949
Amortized Cost	[8]			19,740
Investments, at fair value	[4],[8]			20,061
Investment, Identifier [Axis]: Cox Oil Offshore, LLC, Volumetric Production Payments, Energy—Upstream
Schedule of Investments [Line Items]
Principal  Amount	[11],[17],[32],[33]			100,000
Amortized Cost	[17],[32],[33]			1,129
Investments, at fair value	[4],[17],[32],[33]			$ 1,234
Investment, Identifier [Axis]: Crown SubSea Communication Holding, Inc., Capital Goods
Schedule of Investments [Line Items]
Variable rate	[5],[6]	4.75%
Principal  Amount	[6],[10]	$ 6,000
Amortized Cost	[6]	5,941
Investments, at fair value	[3],[6]	$ 6,042
Investment, Identifier [Axis]: Crown SubSea Communications Holding, Inc., Capital Goods 1
Schedule of Investments [Line Items]
Variable rate	[7],[8],[9]			5%
Principal  Amount	[8],[9],[11]			$ 4,500
Amortized Cost	[8],[9]			4,523
Investments, at fair value	[4],[8],[9]			$ 4,534
Investment, Identifier [Axis]: Crown SubSea Communications Holding, Inc., Capital Goods 2
Schedule of Investments [Line Items]
Variable rate	[7],[8],[9]			5.25%
Principal  Amount	[8],[9],[11]			$ 5,430
Amortized Cost	[8],[9]			5,445
Investments, at fair value	[4],[8],[9]			$ 5,468
Investment, Identifier [Axis]: Delivery Hero Finco LLC, Consumer Services
Schedule of Investments [Line Items]
Variable rate	[5],[16],[29]	5%
Principal  Amount	[10],[16],[29]	$ 20,000
Amortized Cost	[16],[29]	19,900
Investments, at fair value	[3],[16],[29]	$ 19,900
Investment, Identifier [Axis]: Digicel International Finance Ltd., Telecommunication Services
Schedule of Investments [Line Items]
Variable rate	[5],[6]	5.15%
Principal  Amount	[6],[10]	$ 20,000
Amortized Cost	[6]	19,236
Investments, at fair value	[3],[6]	$ 19,400
Investment, Identifier [Axis]: Engineered Machinery Holdings, Inc., Capital Goods
Schedule of Investments [Line Items]
Variable rate		3.75%	[5],[6]	3.50%	[7],[8]
Principal  Amount		$ 24,860	[6],[10]	$ 19,924	[8],[11]
Amortized Cost		24,793	[6]	19,847	[8]
Investments, at fair value		$ 24,806	[3],[6]	$ 19,840	[4],[8]
Investment, Identifier [Axis]: FR XIII PAA Holdings HoldCo, LLC, Energy—Midstream
Schedule of Investments [Line Items]
Variable rate	[7],[8],[17]			7.50%
Principal  Amount	[8],[11],[17]			$ 17,047
Amortized Cost	[8],[17]			16,855
Investments, at fair value	[4],[8],[17]			$ 17,156
Investment, Identifier [Axis]: First Brands Group, LLC, Automobiles & Components
Schedule of Investments [Line Items]
Variable rate		5%	[5],[6]	5%	[7],[8]
Principal  Amount		$ 24,841	[6],[10]	$ 19,905	[8],[11]
Amortized Cost		24,564	[6]	19,620	[8]
Investments, at fair value		24,910	[3],[6]	19,781	[4],[8]
Investment, Identifier [Axis]: Full House Resorts, Inc., Consumer Services
Schedule of Investments [Line Items]
Principal  Amount		25,742	[6],[10]	20,742	[8],[11]
Amortized Cost		23,419	[6]	18,561	[8]
Investments, at fair value		24,622	[3],[6]	19,517	[4],[8]
Investment, Identifier [Axis]: GWP Midstream Holdco, LLC, Common Equity
Schedule of Investments [Line Items]
Investments, at fair value		2,202		1,661		5,044
Investment, Identifier [Axis]: GWP Midstream Holdco, LLC, Common Equity, Energy—Midstream
Schedule of Investments [Line Items]
Amortized Cost		6,681	[14],[20],[23],[31]	6,681	[17],[21],[25],[34]
Investments, at fair value		$ 2,202	[3],[14],[20],[23],[31]	1,661	[4],[17],[21],[25],[34]
Investment, Identifier [Axis]: GasLog Ltd., Energy—Midstream
Schedule of Investments [Line Items]
Variable rate	[5],[14],[16]	7.80%
Principal  Amount		$ 13,951	[10],[14],[16]	13,951	[11],[17],[19]
Amortized Cost		13,877	[14],[16]	13,874	[17],[19]
Investments, at fair value		13,357	[3],[14],[16]	13,510	[4],[17],[19]
Investment, Identifier [Axis]: Global Jet Capital Holdings, LP, Preferred Equity, Commercial & Professional Services 1
Schedule of Investments [Line Items]
Amortized Cost		2,786	[14],[20],[22]	2,786	[17],[21]
Investments, at fair value		0	[3],[14],[20],[22]	0	[4],[17],[21]
Investment, Identifier [Axis]: Global Jet Capital Holdings, LP, Preferred Equity, Commercial & Professional Services 2
Schedule of Investments [Line Items]
Amortized Cost		12,493	[14],[20],[22],[27]	12,493	[17],[21],[28]
Investments, at fair value		$ 10,360	[3],[14],[20],[22],[27]	$ 10,357	[4],[17],[21],[28]
Investment, Identifier [Axis]: Global Tel Link Corp., Technology Hardware & Equipment
Schedule of Investments [Line Items]
Variable rate	[5],[6],[29]	4.25%
Principal  Amount	[6],[10],[29]	$ 14,031
Amortized Cost	[6],[29]	13,599
Investments, at fair value	[3],[6],[29]	$ 13,685
Investment, Identifier [Axis]: Gold Rush Amusements, Inc., Consumer Services
Schedule of Investments [Line Items]
Variable rate		7.50%	[5],[6],[14]	7.50%	[7],[8],[17]
Principal  Amount		$ 30,596	[6],[10],[14]	$ 30,673	[8],[11],[17]
Amortized Cost		30,023	[6],[14]	30,079	[8],[17]
Investments, at fair value		$ 30,328	[3],[6],[14]	$ 30,059	[4],[8],[17]
Investment, Identifier [Axis]: Goodnight Water Solutions, LLC, Energy—Midstream
Schedule of Investments [Line Items]
Variable rate		7%	[5],[6],[14]	7%	[7],[8],[17]
Principal  Amount		$ 14,328	[6],[10],[14]	$ 14,516	[8],[11],[17]
Amortized Cost		14,141	[6],[14]	14,326	[8],[17]
Investments, at fair value		$ 14,238	[3],[6],[14]	$ 14,379	[4],[8],[17]
Investment, Identifier [Axis]: Guardian US Holdco, LLC, Financial Services
Schedule of Investments [Line Items]
Variable rate		3.50%	[5],[6]	4%	[7],[8]
Principal  Amount		$ 24,863	[6],[10]	$ 19,925	[8],[11]
Amortized Cost		24,891	[6]	19,922	[8]
Investments, at fair value		24,959	[3],[6]	20,008	[4],[8]
Investment, Identifier [Axis]: Guitar Center, Inc., Consumer Discretionary Distribution & Retail
Schedule of Investments [Line Items]
Principal  Amount		23,568	[6],[10]	20,000	[8],[11]
Amortized Cost		21,346	[6]	17,987	[8]
Investments, at fair value		20,819	[3],[6]	17,473	[4],[8]
Investment, Identifier [Axis]: Harvest Oil & Gas Corp., Common Equity
Schedule of Investments [Line Items]
Investments, at fair value		344		271		810
Investment, Identifier [Axis]: Harvest Oil & Gas Corp., Common Equity, Energy—Upstream
Schedule of Investments [Line Items]
Amortized Cost		14,418	[14],[20],[31]	14,418	[21],[34]
Investments, at fair value		$ 344	[3],[14],[20],[31]	$ 271	[4],[21],[34]
Investment, Identifier [Axis]: Knowlton Development Corporation Inc., Household & Personal Products
Schedule of Investments [Line Items]
Variable rate		5%	[5],[6]	5%	[7],[8]
Principal  Amount		$ 26,000	[6],[10]	$ 21,000	[8],[11]
Amortized Cost		25,352	[6]	20,370	[8]
Investments, at fair value		$ 26,081	[3],[6]	$ 20,858	[4],[8]
Investment, Identifier [Axis]: LABL, Inc., Commercial & Professional Services
Schedule of Investments [Line Items]
Variable rate	[5],[6]	5%
Principal  Amount	[6],[10]	$ 24,801
Amortized Cost	[6]	24,129
Investments, at fair value	[3],[6]	$ 24,343
Investment, Identifier [Axis]: LABL, Inc., Commerical & Professional Services
Schedule of Investments [Line Items]
Variable rate	[7],[8]			5%
Principal  Amount	[8],[11]			$ 19,864
Amortized Cost	[8]			19,335
Investments, at fair value	[4],[8]			$ 19,106
Investment, Identifier [Axis]: LaserShip, Inc., Transportation
Schedule of Investments [Line Items]
Variable rate	[5],[6]	4.50%
Principal  Amount	[6],[10]	$ 6,982
Amortized Cost	[6]	6,613
Investments, at fair value	[3],[6]	$ 6,523
Investment, Identifier [Axis]: Learning Care Group No. 2 Inc., Consumer Services
Schedule of Investments [Line Items]
Variable rate		4.75%	[5],[6]	4.75%	[7],[8]
Principal  Amount		$ 21,895	[6],[10]	$ 19,950	[8],[11]
Amortized Cost		22,027	[6]	20,070	[8]
Investments, at fair value		21,959	[3],[6]	20,100	[4],[8]
Investment, Identifier [Axis]: Limetree Bay Energy, LLC, Class A Units
Schedule of Investments [Line Items]
Investments, at fair value				0		1,885
Investment, Identifier [Axis]: MBS Services Holdings, LLC, A-3 Units, Commercial & Professional Services
Schedule of Investments [Line Items]
Amortized Cost	[14],[20],[23]	522
Investments, at fair value	[3],[14],[20],[23]	0
Investment, Identifier [Axis]: MBS Services Holdings, LLC, Commercial & Professional Services
Schedule of Investments [Line Items]
Principal  Amount	[10],[14]	28,622
Amortized Cost	[14]	27,569
Investments, at fair value	[3],[14]	28,049
Investment, Identifier [Axis]: Maverick Natural Resources, LLC, Common Equity, Energy—Upstream
Schedule of Investments [Line Items]
Amortized Cost		93,044	[14],[23]	93,044	[17],[21],[25]
Investments, at fair value		$ 78,546	[3],[14],[23]	$ 164,040	[4],[17],[21],[25]
Investment, Identifier [Axis]: Mavis Tire Express Services TopCo, L.P., Consumer Discretionary Distribution & Retail
Schedule of Investments [Line Items]
Variable rate		3.75%	[5],[6]	4%	[7],[8]
Principal  Amount		$ 17,349	[6],[10]	$ 19,893	[8],[11]
Amortized Cost		17,368	[6]	19,797	[8]
Investments, at fair value		17,399	[3],[6]	19,955	[4],[8]
Investment, Identifier [Axis]: NGL Energy Partners, LP, Preferred Equity, Energy—Midstream
Schedule of Investments [Line Items]
Amortized Cost		157,679	[6],[14],[16],[22],[27]	157,633	[8],[17],[19],[21],[28]
Investments, at fair value		222,338	[3],[6],[14],[16],[22],[27]	141,141	[4],[8],[17],[19],[21],[28]
Investment, Identifier [Axis]: NGL Energy Partners, LP, Warrants (Par), Strike, Energy—Midstream
Schedule of Investments [Line Items]
Amortized Cost	[14],[16],[20]	3,083
Investments, at fair value	[3],[14],[16],[20]	2,472
Investment, Identifier [Axis]: NGL Energy Partners, LP, Warrants (Par), Strike, Energy—Midstream 2
Schedule of Investments [Line Items]
Amortized Cost	[14],[16],[20]	630
Investments, at fair value	[3],[14],[16],[20]	589
Investment, Identifier [Axis]: NGL Energy Partners, LP, Warrants (Par), Strike: $13.56, Energy—Midstream
Schedule of Investments [Line Items]
Amortized Cost	[17],[19],[21]			630
Investments, at fair value	[4],[17],[19],[21]			621
Investment, Identifier [Axis]: NGL Energy Partners, LP, Warrants (Par), Strike: $14.54, Energy—Midstream
Schedule of Investments [Line Items]
Amortized Cost	[17],[19],[21]			3,083
Investments, at fair value	[4],[17],[19],[21]			2,682
Investment, Identifier [Axis]: NGL Energy Partners, LP, Warrants (Premium), Strike, Energy—Midstream 1
Schedule of Investments [Line Items]
Amortized Cost	[14],[16],[20]	2,623
Investments, at fair value	[3],[14],[16],[20]	2,808
Investment, Identifier [Axis]: NGL Energy Partners, LP, Warrants (Premium), Strike, Energy—Midstream 2
Schedule of Investments [Line Items]
Amortized Cost	[14],[16],[20]	576
Investments, at fair value	[3],[14],[16],[20]	660
Investment, Identifier [Axis]: NGL Energy Partners, LP, Warrants (Premium), Strike: $16.27, Energy—Midstream
Schedule of Investments [Line Items]
Amortized Cost	[17],[19],[21]			576
Investments, at fair value	[4],[17],[19],[21]			735
Investment, Identifier [Axis]: NGL Energy Partners, LP, Warrants (Premium), Strike: $17.45, Energy—Midstream
Schedule of Investments [Line Items]
Amortized Cost	[17],[19],[21]			2,623
Investments, at fair value	[4],[17],[19],[21]			3,083
Investment, Identifier [Axis]: Navios Logistics Finance, Inc., Transportation
Schedule of Investments [Line Items]
Principal  Amount		25,000	[6],[10],[16]	20,000	[8],[11],[19]
Amortized Cost		24,679	[6],[16]	19,680	[8],[19]
Investments, at fair value		$ 25,013	[3],[6],[16]	$ 19,772	[4],[8],[19]
Investment, Identifier [Axis]: Nephron Pharmaceuticals Corp., Pharmaceuticals, Biotechnology & Life Sciences
Schedule of Investments [Line Items]
Variable rate		9%	[5],[14]	9%	[7],[17]
Principal  Amount		$ 19,925	[10],[14]	$ 20,000	[11],[17]
Amortized Cost		19,434	[14]	19,400	[17]
Investments, at fair value		$ 19,352	[3],[14]	19,300	[4],[17]
Investment, Identifier [Axis]: Osaic Holdings, Inc., Financial Services
Schedule of Investments [Line Items]
Variable rate	[5],[6],[29]	4.50%
Principal  Amount	[6],[10],[29]	$ 4,988
Amortized Cost	[6],[29]	4,988
Investments, at fair value	[3],[6],[29]	5,013
Investment, Identifier [Axis]: Permian Production Holdings, LLC
Schedule of Investments [Line Items]
Investments, at fair value		4,050		4,816		4,767
Investment, Identifier [Axis]: Permian Production Holdings, LLC, Common Equity
Schedule of Investments [Line Items]
Investments, at fair value		1,043		748		11,420
Investment, Identifier [Axis]: Permian Production Holdings, LLC, Common Equity, Energy—Upstream
Schedule of Investments [Line Items]
Amortized Cost		5	[14],[20],[23],[31]	5	[17],[21],[25],[34]
Investments, at fair value		1,043	[3],[14],[20],[23],[31]	748	[4],[17],[21],[25],[34]
Investment, Identifier [Axis]: Permian Production Holdings, LLC, Energy—Upstream
Schedule of Investments [Line Items]
Principal  Amount		4,060	[10],[14],[31]	4,864	[11],[17],[34]
Amortized Cost		3,798	[14],[31]	4,497	[17],[34]
Investments, at fair value		4,050	[3],[14],[31]	$ 4,816	[4],[17],[34]
Investment, Identifier [Axis]: Phoenix Guarantor Inc., Financial Services
Schedule of Investments [Line Items]
Variable rate	[7],[8],[9]			3.50%
Principal  Amount	[8],[9],[11]			$ 19,923
Amortized Cost	[8],[9]			19,891
Investments, at fair value	[4],[8],[9]			19,951
Investment, Identifier [Axis]: Plainfield Renewable Energy Holdings LLC, Energy—Power 2
Schedule of Investments [Line Items]
Principal  Amount	[10],[14],[20],[27]	4,218
Amortized Cost	[14],[20],[27]	3,827
Investments, at fair value	[3],[14],[20],[27]	0
Investment, Identifier [Axis]: Plainfield Renewable Energy Holdings LLC, Energy—Power 1
Schedule of Investments [Line Items]
Principal  Amount		13,936	[10],[14],[20],[27]	13,297	[11],[17],[21],[28]
Amortized Cost		11,926	[14],[20],[27]	12,329	[17],[21],[28]
Investments, at fair value		4,592	[3],[14],[20],[27]	7,473	[4],[17],[21],[28]
Investment, Identifier [Axis]: Plainfield Renewable Energy Holdings LLC, Energy—Power 2
Schedule of Investments [Line Items]
Principal  Amount	[11],[17],[21],[28]			4,015
Amortized Cost	[17],[21],[28]			3,827
Investments, at fair value	[4],[17],[21],[28]			0
Investment, Identifier [Axis]: Plainfield Renewable Energy Holdings LLC, Letter of Credit, Energy—Power
Schedule of Investments [Line Items]
Principal  Amount		2,709	[10],[12],[14]	2,709	[11],[13],[17]
Amortized Cost		2,709	[12],[14]	2,709	[13],[17]
Investments, at fair value		$ 0	[3],[12],[14]	$ 0	[4],[13],[17]
Investment, Identifier [Axis]: Pretium PKG Holdings, Inc., Materials
Schedule of Investments [Line Items]
Variable rate		2.50%	[5],[6]	5%	[7],[8]
Principal  Amount		$ 32,378	[6],[10]	$ 30,118	[8],[11]
Amortized Cost		31,871	[6]	29,634	[8]
Investments, at fair value		$ 32,883	[3],[6]	$ 29,591	[4],[8]
Investment, Identifier [Axis]: Pro Mach Group, Inc., Capital Goods
Schedule of Investments [Line Items]
Variable rate		3.75%	[5],[6]	4%	[7],[8]
Principal  Amount		$ 17,424	[6],[10]	$ 19,924	[8],[11]
Amortized Cost		17,478	[6]	19,979	[8]
Investments, at fair value		$ 17,506	[3],[6]	$ 20,007	[4],[8]
Investment, Identifier [Axis]: Proampac PG Borrower LLC, Materials
Schedule of Investments [Line Items]
Variable rate		4.50%	[5],[6]	4.50%	[7],[8]
Principal  Amount		$ 22,942	[6],[10]	$ 20,000	[8],[11]
Amortized Cost		22,955	[6]	19,994	[8]
Investments, at fair value		$ 23,023	[3],[6]	$ 20,062	[4],[8]
Investment, Identifier [Axis]: RealTruck Group, Inc., Automobiles & Components
Schedule of Investments [Line Items]
Variable rate	[5],[6]	3.50%
Principal  Amount	[6],[10]	$ 24,885
Amortized Cost	[6]	24,066
Investments, at fair value	[3],[6]	$ 24,729
Investment, Identifier [Axis]: Realtruck Group, Inc., Automobiles & Components
Schedule of Investments [Line Items]
Variable rate	[7],[8],[9]			3.50%
Principal  Amount	[8],[9],[11]			$ 19,956
Amortized Cost	[8],[9]			19,117
Investments, at fair value	[4],[8],[9]			19,740
Investment, Identifier [Axis]: Ridgeback Resources Inc., Common Equity
Schedule of Investments [Line Items]
Investments, at fair value				$ 0		41,851
Investment, Identifier [Axis]: Ryan, LLC, Commercial & Professional Services 1
Schedule of Investments [Line Items]
Variable rate	[5],[6]	4.50%
Principal  Amount	[6],[10]	$ 9,844
Amortized Cost	[6]	9,868
Investments, at fair value	[3],[6]	$ 9,905
Investment, Identifier [Axis]: Ryan, LLC, Commercial & Professional Services 2
Schedule of Investments [Line Items]
Variable rate	[5],[12]	4.50%
Principal  Amount	[10],[12]	$ 1,036
Amortized Cost	[12]	1,036
Investments, at fair value	[3],[12]	$ 1,043
Investment, Identifier [Axis]: Ryan, LLC, Commerical & Professional Services 1
Schedule of Investments [Line Items]
Variable rate	[7],[8],[9]			4.50%
Principal  Amount	[8],[9],[11]			$ 9,844
Amortized Cost	[8],[9]			9,868
Investments, at fair value	[4],[8],[9]			$ 9,890
Investment, Identifier [Axis]: Ryan, LLC, Commerical & Professional Services 2
Schedule of Investments [Line Items]
Variable rate	[7],[9],[13]			4.50%
Principal  Amount	[9],[11],[13]			$ 1,036
Amortized Cost	[9],[13]			1,039
Investments, at fair value	[4],[9],[13]			$ 1,041
Investment, Identifier [Axis]: SRS Distribution Inc., Capital Goods
Schedule of Investments [Line Items]
Variable rate		3.50%	[5],[6]	3.50%	[7],[8],[9]
Principal  Amount		$ 24,860	[6],[10]	$ 19,924	[8],[9],[11]
Amortized Cost		24,705	[6]	19,729	[8],[9]
Investments, at fair value		25,060	[3],[6]	19,982	[4],[8],[9]
Investment, Identifier [Axis]: ST EIP Holdings Inc., Energy—Midstream
Schedule of Investments [Line Items]
Principal  Amount		10,311	[6],[10],[14]	10,365	[8],[11],[17]
Amortized Cost		9,914	[6],[14]	9,951	[8],[17]
Investments, at fair value		9,771	[3],[6],[14]	9,874	[4],[8],[17]
Investment, Identifier [Axis]: Sustainable Infrastructure Investments, LLC
Schedule of Investments [Line Items]
Investments, at fair value				39,427		51,098
Investment, Identifier [Axis]: Sustainable Infrastructure Investments, LLC 2
Schedule of Investments [Line Items]
Investments, at fair value		40,830		39,427
Investment, Identifier [Axis]: Sustainable Infrastructure Investments, LLC, Energy—Power
Schedule of Investments [Line Items]
Principal  Amount		60,603	[10],[14],[16],[24]	60,603	[17],[19],[26]
Amortized Cost		43,150	[14],[16],[24]	43,150	[17],[19],[26]
Investments, at fair value		$ 40,830	[3],[14],[16],[24]	$ 39,427	[4],[17],[19],[26]
Investment, Identifier [Axis]: TKC Holdings, Inc., Consumer Staples Distribution & Retail
Schedule of Investments [Line Items]
Variable rate		5.50%	[5],[6]	5.50%	[7],[8]
Principal  Amount		$ 24,536	[6],[10]	$ 19,650	[8],[11]
Amortized Cost		23,460	[6]	18,681	[8]
Investments, at fair value		24,337	[3],[6]	18,830	[4],[8]
Investment, Identifier [Axis]: Telpico, LLC, Common Equity
Schedule of Investments [Line Items]
Investments, at fair value		0		0		0
Investment, Identifier [Axis]: Telpico, LLC, Common Equity, Energy—Upstream
Schedule of Investments [Line Items]
Amortized Cost		0	[14],[20],[23],[31]	0	[17],[21],[25],[34]
Investments, at fair value		0	[3],[14],[20],[23],[31]	0	[4],[17],[21],[25],[34]
Investment, Identifier [Axis]: Tenrgys, LLC, Common Equity, Energy—Upstream
Schedule of Investments [Line Items]
Amortized Cost		7,571	[14],[20],[23]	7,571	[17],[21],[25]
Investments, at fair value		$ 1,245	[3],[14],[20],[23]	$ 4,418	[4],[17],[21],[25]
Investment, Identifier [Axis]: Tenrgys, LLC, Energy—Upstream
Schedule of Investments [Line Items]
Variable rate		7.50%	[5],[6],[14]	7.50%	[7],[8],[17]
Principal  Amount		$ 20,537	[6],[10],[14]	$ 20,537	[8],[11],[17]
Amortized Cost		20,537	[6],[14]	20,537	[8],[17]
Investments, at fair value		$ 20,306	[3],[6],[14]	$ 19,998	[4],[8],[17]
Investment, Identifier [Axis]: TruGreen, LP, Commercial & Professional Services
Schedule of Investments [Line Items]
Variable rate		4%	[5],[6]	4%	[7],[8]
Principal  Amount		$ 24,846	[6],[10]	$ 19,910	[8],[11]
Amortized Cost		23,463	[6]	18,614	[8]
Investments, at fair value		24,230	[3],[6]	19,268	[4],[8]
Investment, Identifier [Axis]: U.S. Treasury Bills, U.S. Treasury 1
Schedule of Investments [Line Items]
Principal  Amount	[35],[36]	100,000
Amortized Cost	[35],[36]	99,826
Investments, at fair value	[3],[35],[36]	99,884
Investment, Identifier [Axis]: U.S. Treasury Bills, U.S. Treasury 2
Schedule of Investments [Line Items]
Principal  Amount	[35],[36]	27,000
Amortized Cost	[35],[36]	26,937
Investments, at fair value	[3],[35],[36]	26,941
Investment, Identifier [Axis]: U.S. Treasury Bills, U.S. Treasury Bills
Schedule of Investments [Line Items]
Principal  Amount	[37]			21,000
Amortized Cost	[37]			20,994
Investments, at fair value	[4],[37]			21,000
Investment, Identifier [Axis]: USA Compression Partners, LP, Preferred Equity, Energy—Midstream
Schedule of Investments [Line Items]
Amortized Cost		71,940	[6],[14],[16],[22]	78,091	[8],[17],[19]
Investments, at fair value		$ 86,324	[3],[6],[14],[16],[22]	98,333	[4],[8],[17],[19]
Investment, Identifier [Axis]: WMK, LLC, Consumer Discretionary Distribution & Retail 1
Schedule of Investments [Line Items]
Variable rate	[5],[6],[14]	6.50%
Principal  Amount	[6],[10],[14]	$ 29,833
Amortized Cost	[6],[14]	28,839
Investments, at fair value	[3],[6],[14]	$ 28,956
Investment, Identifier [Axis]: WMK, LLC, Consumer Discretionary Distribution & Retail 2
Schedule of Investments [Line Items]
Variable rate	[5],[12],[14]	6.50%
Principal  Amount	[10],[12],[14]	$ 5,167
Amortized Cost	[12],[14]	5,167
Investments, at fair value	[3],[12],[14]	5,015
Investment, Identifier [Axis]: Warren Resources, Inc.
Schedule of Investments [Line Items]
Investments, at fair value		23,883		23,823		23,584
Investment, Identifier [Axis]: Warren Resources, Inc., Common Equity
Schedule of Investments [Line Items]
Investments, at fair value		14,417		15,566		$ 36,982
Investment, Identifier [Axis]: Warren Resources, Inc., Common Equity, Energy—Upstream
Schedule of Investments [Line Items]
Amortized Cost		20,881	[14],[20],[24]	20,754	[17],[21],[26]
Investments, at fair value		$ 14,417	[3],[14],[20],[24]	$ 15,566	[4],[17],[21],[26]
Investment, Identifier [Axis]: Warren Resources, Inc., Energy—Upstream
Schedule of Investments [Line Items]
Variable rate		9%	[5],[6],[14],[24]	9%	[7],[8],[17],[26]
Principal  Amount		$ 23,883	[6],[10],[14],[24]	$ 23,823	[8],[11],[17],[26]
Amortized Cost		23,883	[6],[14],[24]	23,823	[8],[17],[26]
Investments, at fair value		$ 23,883	[3],[6],[14],[24]	$ 23,823	[4],[8],[17],[26]
Investment, Identifier [Axis]: Wattbridge Inc., Energy—Power
Schedule of Investments [Line Items]
Variable rate		9.85%	[5],[6],[14]	9.85%	[7],[8],[17]
Principal  Amount		$ 42,938	[6],[10],[14]	$ 42,938	[8],[11],[17]
Amortized Cost		42,938	[6],[14]	42,938	[8],[17]
Investments, at fair value		$ 41,866	[3],[6],[14]	41,882	[4],[8],[17]
Investment, Identifier [Axis]: Weber-Stephen Products LLC, Consumer Durables & Apparel
Schedule of Investments [Line Items]
Variable rate	[5],[6],[29]	3.25%
Principal  Amount	[6],[10],[29]	$ 26,285
Amortized Cost	[6],[29]	24,014
Investments, at fair value	[3],[6],[29]	24,404
Sustainable Infrastructure Investments, LLC
Schedule of Investments [Line Items]
Principal  Amount		153,837		170,083
Amortized Cost		153,837		170,083
Investments, at fair value		$ 154,640		$ 170,949
Percent of net assets		100%		100%
Sustainable Infrastructure Investments, LLC \| Secured Overnight Financing Rate (SOFR)
Schedule of Investments [Line Items]
Variable rate		5.30%		5.33%
Sustainable Infrastructure Investments, LLC \| Net Senior Secured Loans—First Lien
Schedule of Investments [Line Items]
Amortized Cost		$ 153,837		$ 170,083
Investments, at fair value		$ 154,640		$ 170,949
Percent of net assets		100%		100%
Sustainable Infrastructure Investments, LLC \| Investment, Identifier [Axis]: Blue Heron Intermediate Holdco I, LLC, Midstream
Schedule of Investments [Line Items]
Variable rate		1.88%		1.88%
Principal  Amount		$ 30,343		$ 30,661
Amortized Cost		30,343		30,661
Investments, at fair value		$ 30,389		$ 30,692
Sustainable Infrastructure Investments, LLC \| Investment, Identifier [Axis]: Copper Mountain Solar 3, LLC, Renewables
Schedule of Investments [Line Items]
Variable rate		1.88%		1.88%
Principal  Amount		$ 16,104		$ 16,104
Amortized Cost		16,104		16,104
Investments, at fair value		$ 16,217		$ 16,172
Sustainable Infrastructure Investments, LLC \| Investment, Identifier [Axis]: FLNG Liquefaction 2, LLC, Midstream
Schedule of Investments [Line Items]
Variable rate		1.50%		1.50%
Principal  Amount		$ 26,164		$ 26,567
Amortized Cost		26,164		26,567
Investments, at fair value		26,335		26,557
Sustainable Infrastructure Investments, LLC \| Investment, Identifier [Axis]: Largest Portfolio Company Investment
Schedule of Investments [Line Items]
Principal  Amount		$ 57,227		$ 57,227
Sustainable Infrastructure Investments, LLC \| Investment, Identifier [Axis]: NES Hercules Class B Member, LLC, Renewables
Schedule of Investments [Line Items]
Variable rate		1.63%		1.63%
Principal  Amount		$ 23,999		$ 24,176
Amortized Cost		23,999		24,176
Investments, at fair value		$ 24,473		$ 24,769
Sustainable Infrastructure Investments, LLC \| Investment, Identifier [Axis]: ST EIP Holdco LLC, Midstream
Schedule of Investments [Line Items]
Variable rate		2.50%		2.50%
Principal  Amount		$ 57,227		$ 57,227
Amortized Cost		57,227		57,227
Investments, at fair value		$ 57,226		$ 57,143
Sustainable Infrastructure Investments, LLC \| Investment, Identifier [Axis]: Seine Funding, LLC
Schedule of Investments [Line Items]
Variable rate							1.20%
Principal  Amount							$ 634,103
Sustainable Infrastructure Investments, LLC \| Investment, Identifier [Axis]: Top of the World Wind Energy LLC, Renewables
Schedule of Investments [Line Items]
Variable rate				2.13%
Principal  Amount				$ 15,348
Amortized Cost				15,348
Investments, at fair value				$ 15,616

[1]Security may be an obligation of one or more entities affiliated with the named company.[2]Security may be an obligation of one or more entities affiliated with the named company.[3]See Note 8 for additional information regarding the fair value of the Company’s financial instruments.[4]See Note 8 for additional information regarding the fair value of the Company’s financial instruments.[5]Certain variable rate securities in the Company’s portfolio bear interest at a rate determined by a publicly disclosed base rate plus a basis point spread. As of March 31, 2024, the one-month and three-month Secured Overnight Financing Rate, or SOFR, or S, was 5.33% and 5.30%, respectively, and the Overnight Bank Funding Rate, or OBFR, was 5.33%. SOFR based contracts may include a credit spread adjustment that is charged in addition to the base rate and basis point spread. PIK means paid-in-kind. PIK income accruals may be adjusted based on the fair value of the underlying investment. Variable rate securities with no floor rate use the respective benchmark rate in all cases.[6]Security or portion thereof held within FSSL Finance BB AssetCo LLC, a wholly-owned subsidiary of the Company, and is pledged as collateral supporting the obligations outstanding under the repurchase facility with Barclays Bank PLC (see Note 9).[7]Certain variable rate securities in the Company’s portfolio bear interest at a rate determined by a publicly disclosed base rate plus a basis point spread. As of December 31, 2023, the one-month and three-month Secured Overnight Financing Rate, or SOFR, or S, was 5.35% and 5.33%, respectively, and the Overnight Bank Funding Rate, or OBFR, was 5.32%. SOFR based contracts may include a credit spread adjustment that is charged in addition to the base rate and basis point spread. PIK means paid-in-kind. PIK income accruals may be adjusted based on the fair value of the underlying investment. Variable rate securities with no floor rate use the respective benchmark rate in all cases.[8]Security or portion thereof held within FSSL Finance BB AssetCo LLC, a wholly-owned subsidiary of the Company, and is pledged as collateral supporting the obligations outstanding under the repurchase facility with Barclays Bank PLC (see Note 9).[9]Security or portion thereof unsettled as of December 31, 2023.[10]Denominated in U.S. dollars, unless otherwise noted.[11]Denominated in U.S. dollars, unless otherwise noted.[12]Security is an unfunded commitment. The stated rate reflects the spread disclosed at the time of commitment and may not indicate the actual rate received upon funding.[13]Security is an unfunded commitment. The stated rate reflects the spread disclosed at the time of commitment and may not indicate the actual rate received upon funding.[14]Security is classified as Level 3 in the Company’s fair value hierarchy (see Note 8).[15]Security or portion thereof held within FS Power Investments II, LLC, a wholly-owned subsidiary of the Company.[16]The investment is not a qualifying asset under the Investment Company Act of 1940, as amended, or the 1940 Act. A business development company may not acquire any asset other than a qualifying asset, unless, at the time the acquisition is made, qualifying assets represent at least 70% of the business development company’s total assets. As of March 31, 2024, 75.7% of the Company’s total assets represented qualifying assets.[17]Security is classified as Level 3 in the Company’s fair value hierarchy (see Note 8).[18]Security or portion thereof held within FS Power Investments II, LLC, a wholly-owned subsidiary of the Company.[19]The investment is not a qualifying asset under the Investment Company Act of 1940, as amended, or the 1940 Act. A business development company may not acquire any asset other than a qualifying asset, unless, at the time the acquisition is made, qualifying assets represent at least 70% of the business development company’s total assets. As of December 31, 2023, 80.8% of the Company’s total assets represented qualifying assets.[20]Security is non-income producing.[21]Security is non-income producing.[22]Includes $59,698 held in Allspring Government Money Market Fund with a 7-day yield of 5.2% as of March 31, 2024.[23]Security held within FSEP Investments, Inc., a wholly-owned subsidiary of the Company.[24]Under the 1940 Act, the Company generally is deemed to “control” a portfolio company if it owns more than 25% of the portfolio company’s voting securities or it has the power to exercise control over the management or policies of such portfolio company. As of March 31, 2024, the Company held investments in portfolio companies of which it is deemed to be an “affiliated person” of and deemed to “control.” The following table presents certain information with respect to investments in portfolio companies of which the Company was deemed to be an affiliated person and deemed to control as of March 31, 2024: Portfolio Company Fair Value at December 31, 2023 Gross Additions (1) Gross Reductions (2) Net Realized Gain (Loss) Net Change in Unrealized Appreciation (Depreciation) Fair Value at March 31, 2024 Interest Income (3) PIK Income (3) Senior Secured Loans—First Lien Allied Wireline Services, LLC $ 22,200 $ — $ — $ — $ (14,965) $ 7,235 $ — $ — Warren Resources, Inc. 23,823 60 — — — 23,883 881 60 Sustainable Infrastructure Investments, LLC Sustainable Infrastructure Investments, LLC 39,427 — — — 1,403 40,830 — — Equity/Other Allied Wireline Services, LLC, Common Equity — — — — — — — — Allied Wireline Services, LLC, Warrants — — — — — — — — Warren Resources, Inc., Common Equity 15,566 127 — — (1,276) 14,417 — — $ 101,016 $ 187 $ — $ — $ (14,838) $ 86,365 $ 881 $ 60 _____________ (1) Gross additions may include increases in the cost basis of investments resulting from new portfolio investments, PIK interest, the amortization of unearned income, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company into this category from a different category. (2) Gross reductions may include decreases in the cost basis of investments resulting from principal collections related to investment repayments or sales, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company out of this category into a different category. (3) Interest and PIK income presented for the three months ended March 31, 2024. Portfolio Company Fair Value at December 31, 2022 Gross Additions (1) Gross Reductions (2) Net Realized Gain (Loss) Net Change in Unrealized Appreciation (Depreciation) Fair Value at December 31, 2023 Interest Income (3) PIK Income (3) Dividend Income (3) Senior Secured Loans—First Lien Allied Downhole Technologies, LLC $ 8,436 $ 138 $ (8,574) $ — $ — $ — $ 256 $ 139 $ — Allied Wireline Services, LLC 63,888 6,389 — — (48,077) 22,200 — 2,910 — Warren Resources, Inc. 23,584 239 — — — 23,823 3,464 179 — Sustainable Infrastructure Investments, LLC Sustainable Infrastructure Investments, LLC 51,098 — (11,364) — (307) 39,427 — — 8,324 Equity/Other Allied Wireline Services, LLC, Common Equity 10,463 — — — (10,463) — — — — Allied Wireline Services, LLC, Warrants — — — — — — — — — Warren Resources, Inc., Common Equity 36,982 — — — (21,416) 15,566 — — — $ 194,451 $ 6,766 $ (19,938) $ — $ (80,263) $ 101,016 $ 3,720 $ 3,228 $ 8,324 _____________ (1) Gross additions may include increases in the cost basis of investments resulting from new portfolio investments, PIK interest, the amortization of unearned income, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company into this category from a different category. (2) Gross reductions may include decreases in the cost basis of investments resulting from principal collections related to investment repayments or sales, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company out of this category into a different category. (3) Interest, PIK and dividend income presented for the year ended December 31, 2023. Portfolio Company Fair Value at December 31, 2023 Gross Additions (1) Gross Reductions (2) Net Realized Gain (Loss) Net Change in Unrealized Appreciation (Depreciation) Fair Value at March 31, 2024 Interest Income (3) PIK Income (3) Senior Secured Loans—First Lien Permian Production Holdings, LLC $ 4,816 $ 58 $ (828) $ 71 $ (67) $ 4,050 $ 160 $ 23 Asset Based Finance Bridge Street Warehouse CLO IV Ltd. — 20,329 — — — 20,329 — 329 Equity/Other GWP Midstream Holdco, LLC, Common Equity 1,661 — — — 541 2,202 — — Harvest Oil & Gas Corp., Common Equity 271 — — — 73 344 — — Permian Production Holdings, LLC, Common Equity 748 — — — 295 1,043 — — Telpico, LLC, Common Equity — — — — — — — — $ 7,496 $ 20,387 $ (828) $ 71 $ 842 $ 27,968 $ 160 $ 352 _____________ (1) Gross additions may include increases in the cost basis of investments resulting from new portfolio investments, PIK interest, the amortization of unearned income, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company into this category from a different category. (2) Gross reductions may include decreases in the cost basis of investments resulting from principal collections related to investment repayments or sales, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company out of this category into a different category. (3) Interest and PIK income presented for the three months ended March 31, 2024. Portfolio Company Fair Value at December 31, 2022 Gross Additions (1) Gross Reductions (2) Net Realized Gain (Loss) Net Change in Unrealized Appreciation (Depreciation) Fair Value at December 31, 2023 Interest Income (3) PIK Income (3) Senior Secured Loans—First Lien Permian Production Holdings, LLC $ 4,767 $ 231 $ — $ — $ (182) $ 4,816 $ 675 $ 97 Equity/Other GWP Midstream Holdco, LLC, Common Equity 5,044 — (3,112) 3,112 (3,383) 1,661 — — Harvest Oil & Gas Corp., Common Equity 810 — (641) — 102 271 — — Limetree Bay Energy, LLC, Class A Units 1,885 246 — (21,704) 19,573 — — — Permian Production Holdings, LLC, Common Equity 11,420 — — — (10,672) 748 — — Ridgeback Resources Inc., Common Equity 41,851 — (35,240) (11,359) 4,748 — — — Telpico, LLC, Common Equity — — — — — — — — $ 65,777 $ 477 $ (38,993) $ (29,951) $ 10,186 $ 7,496 $ 675 $ 97 _____________ (1) Gross additions may include increases in the cost basis of investments resulting from new portfolio investments, PIK interest, the amortization of unearned income, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company into this category from a different category. (2) Gross reductions may include decreases in the cost basis of investments resulting from principal collections related to investment repayments or sales, the exchange of one or more existing securities for one or more new securities and/or the movement of an existing portfolio company out of this category into a different category. (3) Interest and PIK income presented for the year ended December 31, 2023.

Investment Portfolio - Balance

Investment Portfolio - Balance Sheet Information for SIIJV (Details) - USD ($) $ in Thousands	Mar. 31, 2024		Dec. 31, 2023		Mar. 31, 2023	Dec. 31, 2022
Schedule of Investments [Line Items]
Investments, at fair value	$ 1,801,272	[1],[2]	$ 1,523,196	[3],[4]
Cash and other assets	186,949	[1],[2],[5]	486,059	[3],[4],[6]
Total assets	2,047,326		2,059,557
Total liabilities	468,709		497,502
Total shareholders' equity	1,578,617		1,562,055		$ 1,712,828	$ 1,753,748
Sustainable Infrastructure Investments, LLC
Schedule of Investments [Line Items]
Investments, at fair value	154,640		170,949
Cash and other assets	20,017		29,089
Total assets	174,657		200,038
Debt	121,041		145,483
Other liabilities	1,900		3,406
Total liabilities	122,941		148,889
Total shareholders' equity	$ 51,716		$ 51,149

[1]Security may be an obligation of one or more entities affiliated with the named company.[2]See Note 8 for additional information regarding the fair value of the Company’s financial instruments.[3]Security may be an obligation of one or more entities affiliated with the named company.[4]See Note 8 for additional information regarding the fair value of the Company’s financial instruments.[5]Includes $59,698 held in Allspring Government Money Market Fund with a 7-day yield of 5.2% as of March 31, 2024.[6]Includes $23,098 held in Allspring Government Money Market Fund with a 7-day yield of 5.3% as of December 31, 2023.

Investment Portfolio - Operatio

Investment Portfolio - Operations Information for SIIJV (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
Schedule of Investments [Line Items]
Total investment income		$ 69,250	$ 43,095
Interest expense	[1]	9,084	12,598
Administrative services		1,535	1,320
Custodian and accounting fees		919	751
Professional services		125	183
Net expenses		22,037	25,938
Net investment income before taxes		47,213	17,157
Net realized and unrealized gain (loss)		(28,309)	(49,711)
Sustainable Infrastructure Investments, LLC
Schedule of Investments [Line Items]
Total investment income		3,210	4,798
Interest expense		2,090	3,141
Administrative services		32	43
Custodian and accounting fees		46	45
Professional services		38	50
Other		10	10
Net expenses		2,216	3,289
Net investment income before taxes		994	1,509
Net realized and unrealized gain (loss)		(427)	1,946
Net increase (decrease) in net assets resulting from operations		$ 567	$ 3,455

[1]See Note 9 for a discussion of the Company's financing arrangements.

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - Schedule of Fair Value Hierarchy Investments (Details) - USD ($) $ in Thousands	Mar. 31, 2024		Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value	$ 1,801,272	[1],[2]	$ 1,523,196	[3],[4]
Level 1—Price quotations in active markets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value	0		0
Level 2—Significant other observable inputs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value	957,057		683,716
Level 3—Significant unobservable inputs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value	$ 844,215		$ 839,480

[1]Security may be an obligation of one or more entities affiliated with the named company.[2]See Note 8 for additional information regarding the fair value of the Company’s financial instruments.[3]Security may be an obligation of one or more entities affiliated with the named company.[4]See Note 8 for additional information regarding the fair value of the Company’s financial instruments.

Fair Value of Financial Instr_4

Fair Value of Financial Instruments - Assets and Liabilities Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	$ 196	$ 0
Liabilities	0	0
Level 1—Price quotations in active markets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	0	0
Liabilities	0	0
Level 2—Significant other observable inputs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	196	0
Liabilities	0	0
Level 3—Significant unobservable inputs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	0	0
Liabilities	$ 0	$ 0

Fair Value of Financial Instr_5

Fair Value of Financial Instruments - Reconciliation Fair Value, Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Accretion of discount (amortization of premium)	$ 2,161	$ 1,262
Total
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value at beginning of period	839,480	1,594,205
Accretion of discount (amortization of premium)	490	1,050
Purchases	76,110	25,032
Paid-in-kind interest	1,649	4,502
Sales and repayments	(37,267)	(61,981)
Transfers into Level 3	271	810
Transfers out of Level 3	0	0
Fair value at end of period	844,215	1,508,403
The amount of total gains or losses for the period included in changes in net assets attributable to the change in unrealized gains or losses relating to investments still held at the reporting date	(38,072)	(50,742)
Total \| Net realized gain (loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net realized gain (loss)	1,960	(17,800)
Total \| Net change in unrealized appreciation (depreciation)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net realized gain (loss)	(38,478)	(37,415)
Senior Secured Loans—First Lien
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value at beginning of period	237,307	443,245
Accretion of discount (amortization of premium)	363	349
Purchases	28,839	24,949
Paid-in-kind interest	291	2,395
Sales and repayments	(28,252)	(8,110)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Fair value at end of period	221,096	454,083
The amount of total gains or losses for the period included in changes in net assets attributable to the change in unrealized gains or losses relating to investments still held at the reporting date	(17,988)	(8,789)
Senior Secured Loans—First Lien \| Net realized gain (loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net realized gain (loss)	942	(2,806)
Senior Secured Loans—First Lien \| Net change in unrealized appreciation (depreciation)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net realized gain (loss)	(18,394)	(5,939)
Senior Secured Loans—Second Lien
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value at beginning of period	54,424	143,270
Accretion of discount (amortization of premium)	13	81
Purchases	26,540	0
Paid-in-kind interest	1,029	0
Sales and repayments	(1,000)	(15,545)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Fair value at end of period	81,936	128,043
The amount of total gains or losses for the period included in changes in net assets attributable to the change in unrealized gains or losses relating to investments still held at the reporting date	930	228
Senior Secured Loans—Second Lien \| Net realized gain (loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net realized gain (loss)	0	9
Senior Secured Loans—Second Lien \| Net change in unrealized appreciation (depreciation)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net realized gain (loss)	930	228
Senior Secured Bonds
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value at beginning of period	9,874	10,074
Accretion of discount (amortization of premium)	14	12
Purchases	0	0
Paid-in-kind interest	0	0
Sales and repayments	(53)	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Fair value at end of period	9,771	10,164
The amount of total gains or losses for the period included in changes in net assets attributable to the change in unrealized gains or losses relating to investments still held at the reporting date	(66)	78
Senior Secured Bonds \| Net realized gain (loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net realized gain (loss)	2	0
Senior Secured Bonds \| Net change in unrealized appreciation (depreciation)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net realized gain (loss)	(66)	78
Asset Based Finance
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value at beginning of period	0
Accretion of discount (amortization of premium)	0
Purchases	20,000
Paid-in-kind interest	329
Sales and repayments	0
Transfers into Level 3	0
Transfers out of Level 3	0
Fair value at end of period	20,329
The amount of total gains or losses for the period included in changes in net assets attributable to the change in unrealized gains or losses relating to investments still held at the reporting date	0
Asset Based Finance \| Net realized gain (loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net realized gain (loss)	0
Asset Based Finance \| Net change in unrealized appreciation (depreciation)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net realized gain (loss)	0
Unsecured Debt
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value at beginning of period		54,374
Accretion of discount (amortization of premium)		29
Purchases		0
Paid-in-kind interest		2,107
Sales and repayments		(500)
Transfers into Level 3		0
Transfers out of Level 3		0
Fair value at end of period		56,043
The amount of total gains or losses for the period included in changes in net assets attributable to the change in unrealized gains or losses relating to investments still held at the reporting date		28
Unsecured Debt \| Net realized gain (loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net realized gain (loss)		5
Unsecured Debt \| Net change in unrealized appreciation (depreciation)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net realized gain (loss)		28
Preferred Equity
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value at beginning of period	259,990	400,414
Accretion of discount (amortization of premium)	100	579
Purchases	46	0
Paid-in-kind interest	0	0
Sales and repayments	(7,267)	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Fair value at end of period	324,731	414,699
The amount of total gains or losses for the period included in changes in net assets attributable to the change in unrealized gains or losses relating to investments still held at the reporting date	70,846	13,706
Preferred Equity \| Net realized gain (loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net realized gain (loss)	1,016	0
Preferred Equity \| Net change in unrealized appreciation (depreciation)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net realized gain (loss)	70,846	13,706
Sustainable Infrastructure Investments, LLC
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value at beginning of period	39,427	51,098
Accretion of discount (amortization of premium)	0	0
Purchases	0	0
Paid-in-kind interest	0	0
Sales and repayments	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Fair value at end of period	40,830	52,937
The amount of total gains or losses for the period included in changes in net assets attributable to the change in unrealized gains or losses relating to investments still held at the reporting date	1,403	1,839
Sustainable Infrastructure Investments, LLC \| Net realized gain (loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net realized gain (loss)	0	0
Sustainable Infrastructure Investments, LLC \| Net change in unrealized appreciation (depreciation)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net realized gain (loss)	1,403	1,839
Equity/Other
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value at beginning of period	238,458	491,730
Accretion of discount (amortization of premium)	0	0
Purchases	685	83
Paid-in-kind interest	0	0
Sales and repayments	(695)	(37,826)
Transfers into Level 3	271	810
Transfers out of Level 3	0	0
Fair value at end of period	145,522	392,434
The amount of total gains or losses for the period included in changes in net assets attributable to the change in unrealized gains or losses relating to investments still held at the reporting date	(93,197)	(57,832)
Equity/Other \| Net realized gain (loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net realized gain (loss)	0	(15,008)
Equity/Other \| Net change in unrealized appreciation (depreciation)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net realized gain (loss)	$ (93,197)	$ (47,355)

Fair Value of Financial Instr_6

Fair Value of Financial Instruments - Schedule of Valuation Techniques and Significant Unobservable Inputs Used in Recurring Level 3 Fair Value (Details) $ in Thousands	Mar. 31, 2024 USD ($) MMcfe / d Bcfe		Dec. 31, 2023 USD ($) MMcfe / d
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, at fair value	$ 1,801,272	[1],[2]	$ 1,523,196	[3],[4]
Level 3—Significant unobservable inputs
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, at fair value	844,215		839,480
Level 3—Significant unobservable inputs \| Net Senior Secured Loans—First Lien \| Market Comparables
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, at fair value	$ 168,409		$ 212,250
Level 3—Significant unobservable inputs \| Net Senior Secured Loans—First Lien \| Market Comparables \| Minimum \| Market Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.084		0.082
Level 3—Significant unobservable inputs \| Net Senior Secured Loans—First Lien \| Market Comparables \| Minimum \| EBITDA Multiples
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	2.5		3.9
Level 3—Significant unobservable inputs \| Net Senior Secured Loans—First Lien \| Market Comparables \| Maximum \| Market Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.205		0.205
Level 3—Significant unobservable inputs \| Net Senior Secured Loans—First Lien \| Market Comparables \| Maximum \| EBITDA Multiples
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	3.5		4.6
Level 3—Significant unobservable inputs \| Net Senior Secured Loans—First Lien \| Market Comparables \| Weighted Average \| Market Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.140		0.136
Level 3—Significant unobservable inputs \| Net Senior Secured Loans—First Lien \| Market Comparables \| Weighted Average \| EBITDA Multiples
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	3		4.4
Level 3—Significant unobservable inputs \| Net Senior Secured Loans—First Lien \| Discounted Cash Flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, at fair value	$ 2,388		$ 4,807
Level 3—Significant unobservable inputs \| Net Senior Secured Loans—First Lien \| Discounted Cash Flow \| Minimum \| Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.090		0.090
Level 3—Significant unobservable inputs \| Net Senior Secured Loans—First Lien \| Discounted Cash Flow \| Maximum \| Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.110		0.130
Level 3—Significant unobservable inputs \| Net Senior Secured Loans—First Lien \| Discounted Cash Flow \| Weighted Average \| Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.100		0.108
Level 3—Significant unobservable inputs \| Net Senior Secured Loans—First Lien \| Other
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, at fair value	$ 50,299		$ 20,250
Level 3—Significant unobservable inputs \| Net Senior Secured Loans—Second Lien \| Market Comparables
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, at fair value	$ 53,887		$ 54,424
Level 3—Significant unobservable inputs \| Net Senior Secured Loans—Second Lien \| Market Comparables \| Minimum \| Market Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.120		0.125
Level 3—Significant unobservable inputs \| Net Senior Secured Loans—Second Lien \| Market Comparables \| Maximum \| Market Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.143		0.140
Level 3—Significant unobservable inputs \| Net Senior Secured Loans—Second Lien \| Market Comparables \| Weighted Average \| Market Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.130		0.131
Level 3—Significant unobservable inputs \| Net Senior Secured Loans—Second Lien \| Other
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, at fair value	$ 28,049
Level 3—Significant unobservable inputs \| Senior Secured Bonds \| Market Comparables
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, at fair value	$ 9,771		$ 9,874
Level 3—Significant unobservable inputs \| Senior Secured Bonds \| Market Comparables \| Minimum \| Market Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.075		0.075
Level 3—Significant unobservable inputs \| Senior Secured Bonds \| Market Comparables \| Maximum \| Market Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.090		0.085
Level 3—Significant unobservable inputs \| Senior Secured Bonds \| Market Comparables \| Weighted Average \| Market Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.083		0.080
Level 3—Significant unobservable inputs \| Asset Based Finance \| Income
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, at fair value	$ 20,329
Level 3—Significant unobservable inputs \| Asset Based Finance \| Income \| Minimum \| Excess Spread
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.016
Level 3—Significant unobservable inputs \| Asset Based Finance \| Income \| Maximum \| Excess Spread
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.016
Level 3—Significant unobservable inputs \| Asset Based Finance \| Income \| Weighted Average \| Excess Spread
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.016
Level 3—Significant unobservable inputs \| Preferred Equity \| Market Comparables
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, at fair value	$ 319,022		$ 259,990
Level 3—Significant unobservable inputs \| Preferred Equity \| Market Comparables \| Minimum \| Market Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.113		0.100
Level 3—Significant unobservable inputs \| Preferred Equity \| Market Comparables \| Minimum \| EBITDA Multiples
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input			12
Level 3—Significant unobservable inputs \| Preferred Equity \| Market Comparables \| Minimum \| Net Aircraft Book Value Multiple
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	1		1
Level 3—Significant unobservable inputs \| Preferred Equity \| Market Comparables \| Maximum \| Market Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.185		0.230
Level 3—Significant unobservable inputs \| Preferred Equity \| Market Comparables \| Maximum \| EBITDA Multiples
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input			13
Level 3—Significant unobservable inputs \| Preferred Equity \| Market Comparables \| Maximum \| Net Aircraft Book Value Multiple
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	1.1		1.1
Level 3—Significant unobservable inputs \| Preferred Equity \| Market Comparables \| Weighted Average \| Market Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.160		0.175
Level 3—Significant unobservable inputs \| Preferred Equity \| Market Comparables \| Weighted Average \| EBITDA Multiples
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input			12.5
Level 3—Significant unobservable inputs \| Preferred Equity \| Market Comparables \| Weighted Average \| Net Aircraft Book Value Multiple
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	1		1
Level 3—Significant unobservable inputs \| Preferred Equity \| Other
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, at fair value	$ 5,709
Level 3—Significant unobservable inputs \| Sustainable Infrastructure Investments, LLC \| Discounted Cash Flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, at fair value	$ 40,830		$ 39,427
Level 3—Significant unobservable inputs \| Sustainable Infrastructure Investments, LLC \| Discounted Cash Flow \| Minimum \| Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.075		0.080
Level 3—Significant unobservable inputs \| Sustainable Infrastructure Investments, LLC \| Discounted Cash Flow \| Maximum \| Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.100		0.100
Level 3—Significant unobservable inputs \| Sustainable Infrastructure Investments, LLC \| Discounted Cash Flow \| Weighted Average \| Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.088		0.090
Level 3—Significant unobservable inputs \| Equity/Other \| Market Comparables
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, at fair value	$ 44,650		$ 51,160
Level 3—Significant unobservable inputs \| Equity/Other \| Market Comparables \| Minimum \| EBITDA Multiples
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	2.5		2.7
Level 3—Significant unobservable inputs \| Equity/Other \| Market Comparables \| Minimum \| Production Multiples (MMcfe/d)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input \| MMcfe / d	2,750		3,000
Level 3—Significant unobservable inputs \| Equity/Other \| Market Comparables \| Minimum \| Proved Reserves Multiples (Bcfe)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.7		0.7
Level 3—Significant unobservable inputs \| Equity/Other \| Market Comparables \| Minimum \| PV-10 Multiples
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	1.5		0.3
Level 3—Significant unobservable inputs \| Equity/Other \| Market Comparables \| Maximum \| EBITDA Multiples
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	9.3		13
Level 3—Significant unobservable inputs \| Equity/Other \| Market Comparables \| Maximum \| Production Multiples (MMcfe/d)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input \| MMcfe / d	3,350		3,600
Level 3—Significant unobservable inputs \| Equity/Other \| Market Comparables \| Maximum \| Proved Reserves Multiples (Bcfe)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.7		0.7
Level 3—Significant unobservable inputs \| Equity/Other \| Market Comparables \| Maximum \| PV-10 Multiples
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	1.7		0.4
Level 3—Significant unobservable inputs \| Equity/Other \| Market Comparables \| Weighted Average \| EBITDA Multiples
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	6.3		6
Level 3—Significant unobservable inputs \| Equity/Other \| Market Comparables \| Weighted Average \| Production Multiples (MMcfe/d)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input \| MMcfe / d	3,050		3,300
Level 3—Significant unobservable inputs \| Equity/Other \| Market Comparables \| Weighted Average \| Proved Reserves Multiples (Bcfe)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.7		0.7
Level 3—Significant unobservable inputs \| Equity/Other \| Market Comparables \| Weighted Average \| PV-10 Multiples
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	1.6		0.3
Level 3—Significant unobservable inputs \| Equity/Other \| Discounted Cash Flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, at fair value	$ 80,339		$ 166,946
Level 3—Significant unobservable inputs \| Equity/Other \| Discounted Cash Flow \| Minimum \| Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.080		0.080
Level 3—Significant unobservable inputs \| Equity/Other \| Discounted Cash Flow \| Maximum \| Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.120		0.171
Level 3—Significant unobservable inputs \| Equity/Other \| Discounted Cash Flow \| Weighted Average \| Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.100		0.165
Level 3—Significant unobservable inputs \| Equity/Other \| Other
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, at fair value	$ 14,004		$ 13,231
Level 3—Significant unobservable inputs \| Equity/Other \| Option Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments, at fair value	$ 6,529		$ 7,121
Level 3—Significant unobservable inputs \| Equity/Other \| Option Valuation Model \| Minimum \| Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.500		0.550
Level 3—Significant unobservable inputs \| Equity/Other \| Option Valuation Model \| Maximum \| Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.600		0.650
Level 3—Significant unobservable inputs \| Equity/Other \| Option Valuation Model \| Weighted Average \| Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.550		0.600

[1]Security may be an obligation of one or more entities affiliated with the named company.[2]See Note 8 for additional information regarding the fair value of the Company’s financial instruments.[3]Security may be an obligation of one or more entities affiliated with the named company.[4]See Note 8 for additional information regarding the fair value of the Company’s financial instruments.

Financing Arrangement - Outstan

Financing Arrangement - Outstanding Financing Arrangements (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023	Sep. 06, 2023	Mar. 31, 2023
Debt Instrument [Line Items]
Average outstanding	8.47%			8.31%
Barclays Facility \| Line of Credit
Debt Instrument [Line Items]
Amount  Outstanding	$ 400,000	$ 400,000
Amount  Available	$ 100,000	$ 100,000
Barclays Facility \| Line of Credit \| Secured Overnight Financing Rate
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	3%	3%
Debt instrument, variable rate floor	0%	0%
Average outstanding	3%	3%	3%

Financing Arrangement - Interes

Financing Arrangement - Interest Expense (Details) - USD ($) $ in Thousands		3 Months Ended
	May 15, 2023	Mar. 31, 2024	Mar. 31, 2023
Short-Term Debt [Line Items]
Direct Interest Expense		$ 8,568	$ 11,360
Amortization of Deferred Financing Costs		516	1,238
Total Interest Expense		9,084	12,598
Secured Debt \| Debt Instrument, Redemption, Period One
Short-Term Debt [Line Items]
Redemption percentage	100%
Senior Notes \| Debt Instrument, Redemption, Period One
Short-Term Debt [Line Items]
Redemption percentage	100%
Senior Notes \| Debt Instrument, Redemption, Period Two
Short-Term Debt [Line Items]
Redemption percentage	100%
Barclays Facility \| Line of Credit
Short-Term Debt [Line Items]
Direct Interest Expense		8,568	0
Amortization of Deferred Financing Costs		516	0
Total Interest Expense		9,084	0
JPMorgan Facility \| Line of Credit
Short-Term Debt [Line Items]
Direct Interest Expense		0	2,790
Amortization of Deferred Financing Costs		0	238
Total Interest Expense		0	3,028
Senior Secured Notes \| Secured Debt
Short-Term Debt [Line Items]
Direct Interest Expense		0	8,570
Amortization of Deferred Financing Costs		0	1,000
Total Interest Expense		$ 0	$ 9,570

Financing Arrangement - Narrati

Financing Arrangement - Narrative (Details)				3 Months Ended		12 Months Ended
Financing Arrangement - Narrative (Details)	Sep. 06, 2023 USD ($) subsidiary	May 15, 2023	Feb. 14, 2023 USD ($)	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2023	Aug. 16, 2018 USD ($)
Debt Instrument [Line Items]
Amount outstanding				$ 400,000,000	$ 606,516,000
Average outstanding				8.47%	8.31%
Debt instrument, interest rate, effective percentage				8.73%	7.50%
Number of finance subsidiaries \| subsidiary	2
Secured Debt \| Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Redemption percentage		100%
Senior Notes \| Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Redemption percentage		100%
Senior Notes \| Debt Instrument, Redemption, Period Two
Debt Instrument [Line Items]
Redemption percentage		100%
Barclays Facility \| Secured Overnight Financing Rate \| Minimum
Debt Instrument [Line Items]
Average outstanding	1.90%
Barclays Facility \| Secured Overnight Financing Rate \| Maximum
Debt Instrument [Line Items]
Average outstanding	4.20%
Barclays Facility \| Line of Credit
Debt Instrument [Line Items]
Maximum aggregate purchase price	$ 500,000
Initial purchase price				$ 400,000
Aggregate principal amount				400,000
Facilities payable	394,953,000
Deferred financing costs	$ 6,199,000			$ 5,047,000
Barclays Facility \| Line of Credit \| Secured Overnight Finance Rating (SOFR)
Debt Instrument [Line Items]
Debt instrument, variable rate floor	0%
Barclays Facility \| Line of Credit \| Secured Overnight Financing Rate
Debt Instrument [Line Items]
Average outstanding	3%			3%		3%
Debt instrument, variable rate floor				0%		0%
Basis spread on variable rate (percent)				3%		3%
JPMorgan Facility \| Line of Credit
Debt Instrument [Line Items]
Debt instrument, variable rate floor			0%
Principal amount outstanding			$ 305,676,000
JPMorgan Facility \| Line of Credit \| London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate (percent)			3%
Senior Secured Notes \| Secured Debt
Debt Instrument [Line Items]
Principal amount outstanding							$ 500,000,000
Stated interest rate							7.50%

Financial Highlights (Details)

Financial Highlights (Details) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2024 USD ($) $ / shares shares	Mar. 31, 2023 USD ($) $ / shares	Dec. 31, 2023 USD ($) $ / shares shares	Dec. 31, 2022 USD ($)
Investment Company, Financial Highlights [Roll Forward]
Net asset value, beginning of period (in USD per Share)	$ 3.43	$ 3.88	$ 3.88
Results of operations
Net investment income (in USD per share)	0.10		0.18
Net realized gain (loss) and unrealized appreciation (depreciation) (in USD per share)	(0.06)		(0.44)
Net increase (decrease) in net assets resulting from operations (in USD per share)	0.04		(0.26)
Distribution Amount
Distributions from net investment income (in USD per share)	0		(0.19)
Net decrease in net assets resulting from shareholder distributions (in USD per share)	(0.0034)	$ (0.0300)	(0.19)
Capital share transactions
Issuance of common shares (in USD per share)	0		0
Net increase (decrease) in net assets resulting from capital share transactions (in USD per share)	0		0
Net asset value, end of period (in USD per share)	$ 3.47		$ 3.43
Shares outstanding, end of period (in shares) \| shares	455,506,155		455,506,155
Total return	1.27%		(6.89%)
Total return (without assuming reinvestment of distributions)	1.17%		(6.70%)
Ratio/Supplemental Data:
Net assets, end of period \| $	$ 1,578,617	$ 1,712,828	$ 1,562,055	$ 1,753,748
Ratio of net investment income to average net assets	11.80%		4.77%
Ratio of total operating expenses to average net assets	5.80%		4.50%
Ratio of management fee offset to average net assets	0%		(0.02%)
Ratio of net operating expenses to average net assets	5.80%		4.48%
Ratio of interest expense to average net assets	2.31%		1.39%
Portfolio turnover	7.94%		45.84%
Total amount of senior securities outstanding, exclusive of treasury securities \| $	$ 400,000		$ 400,000
Asset coverage per unit (in USD per share)	$ 4,947		$ 4,905
Asset coverage ratio	4.95		4.91
Ratio of net investment income to average net assets if advisor had not agreement to offset management fee payable	11.80%		4.75%