Main Street Capital Corporation Annual report [Section 13 and 15(d), not S-K Item 405]

Annual report [Section 13 and 15(d), not S-K Item 405]

Consolidated Schedule of Investments In and Advances to Affiliates - Footnotes (Details)

Consolidated Schedule of Investments In and Advances to Affiliates - Footnotes (Details) - USD ($)
$ in Thousands

Dec. 31, 2024

Dec. 31, 2023

Dec. 31, 2022

Schedule of Investments [Line Items]

$ 4,932,669

^[1]

$ 4,286,271

^[2]

Control investments

Schedule of Investments [Line Items]

2,087,890

^[1],[3]

2,006,698

^[2],[4]

$ 1,703,172

Control investments | Midwest

Schedule of Investments [Line Items]

$ 538,212

$ 513,943

Net assets, percentage (as a percent)

19.20%

20.70%

Control investments | Northeast Region and Canada

Schedule of Investments [Line Items]

$ 155,171

$ 268,905

Net assets, percentage (as a percent)

5.50%

10.90%

Control investments | Southeast

Schedule of Investments [Line Items]

$ 69,884

$ 52,278

Net assets, percentage (as a percent)

2.50%

2.10%

Control investments | Southwest

Schedule of Investments [Line Items]

$ 943,892

$ 767,606

Net assets, percentage (as a percent)

33.70%

31.00%

Control investments | West

Schedule of Investments [Line Items]

$ 380,731

$ 403,966

Net assets, percentage (as a percent)

13.60%

16.30%

Affiliate investments

Schedule of Investments [Line Items]

$ 846,798

^[1],[5]

$ 615,002

^[2],[6]

$ 618,359

Affiliate investments | Midwest

Schedule of Investments [Line Items]

$ 235,058

$ 76,330

Net assets, percentage (as a percent)

8.40%

3.10%

Affiliate investments | Northeast Region and Canada

Schedule of Investments [Line Items]

$ 125,084

$ 114,389

Net assets, percentage (as a percent)

4.50%

4.60%

Affiliate investments | Southeast

Schedule of Investments [Line Items]

$ 155,663

$ 176,466

Net assets, percentage (as a percent)

5.60%

7.10%

Affiliate investments | Southwest

Schedule of Investments [Line Items]

$ 167,966

$ 110,303

Net assets, percentage (as a percent)

6.00%

4.50%

Affiliate investments | West

Schedule of Investments [Line Items]

$ 163,027

$ 137,514

Net assets, percentage (as a percent)

5.80%

5.60%

[1]	Investment fair value was determined using significant unobservable inputs, unless otherwise noted. See Note C—Fair Value Hierarchy for Investments—Portfolio Composition for further discussion. Negative fair value is the result of the capitalized discount on the loan or the unfunded commitment being valued below par.
[2]	Investment fair value was determined using significant unobservable inputs, unless otherwise noted. See Note C — Fair Value Hierarchy for Investments — Portfolio Composition for further discussion. Negative fair value is the result of the capitalized discount on the loan or the unfunded commitment being valued below par.
[3]	Control investments are defined by the 1940 Act as investments in which more than 25% of the voting securities are owned or where the ability to nominate greater than 50% of the board representation is maintained.
[4]	Control investments are defined by the 1940 Act as investments in which more than 25% of the voting securities are owned or where the ability to nominate greater than 50% of the board representation is maintained.
[5]	Affiliate investments are defined by the 1940 Act as investments in which between 5% and 25% (inclusive) of the voting securities are owned and the investments are not classified as Control investments.
[6]	Affiliate investments are defined by the 1940 Act as investments in which between 5% and 25% (inclusive) of the voting securities are owned and the investments are not classified as Control investments.