Main Street Capital Corporation Quarterly report pursuant to Section 13 or 15(d)

Quarterly report pursuant to Section 13 or 15(d)

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

Mar. 31, 2024

Dec. 31, 2023

^[2]

Mar. 31, 2023

Dec. 31, 2022

Schedule of Investments [Line Items]

$ 4,548,027

^[1]

$ 4,286,271

Control investments

Schedule of Investments [Line Items]

2,051,212

^[1],[3]

2,006,698

^[4]

$ 1,746,003

$ 1,703,172

Control investments | Midwest

Schedule of Investments [Line Items]

$ 526,552

$ 444,151

Net assets, percentage (as a percent)

20.90%

20.40%

Control investments | Northeast

Schedule of Investments [Line Items]

$ 163,180

Net assets, percentage (as a percent)

7.50%

Control investments | Southeast

Schedule of Investments [Line Items]

$ 51,001

$ 49,003

Net assets, percentage (as a percent)

2.00%

2.30%

Control investments | Southwest

Schedule of Investments [Line Items]

$ 792,668

$ 639,016

Net assets, percentage (as a percent)

31.50%

29.50%

Control investments | West

Schedule of Investments [Line Items]

$ 402,283

$ 450,653

Net assets, percentage (as a percent)

16.00%

20.70%

Control investments | Northeast Region and Canada

Schedule of Investments [Line Items]

$ 278,708

Net assets, percentage (as a percent)

11.10%

Affiliate investments

Schedule of Investments [Line Items]

$ 665,949

^[1],[5]

$ 615,002

^[6]

$ 626,227

$ 618,359

Affiliate investments | Midwest

Schedule of Investments [Line Items]

$ 87,195

$ 77,468

Net assets, percentage (as a percent)

3.50%

3.60%

Affiliate investments | Northeast

Schedule of Investments [Line Items]

$ 109,543

Net assets, percentage (as a percent)

5.00%

Affiliate investments | Southeast

Schedule of Investments [Line Items]

$ 175,963

$ 200,667

Net assets, percentage (as a percent)

7.00%

9.20%

Affiliate investments | Southwest

Schedule of Investments [Line Items]

$ 146,767

$ 84,732

Net assets, percentage (as a percent)

5.80%

3.90%

Affiliate investments | West

Schedule of Investments [Line Items]

$ 137,091

$ 153,817

Net assets, percentage (as a percent)

5.40%

7.10%

Affiliate investments | Northeast Region and Canada

Schedule of Investments [Line Items]

$ 118,933

Net assets, percentage (as a percent)

4.70%

[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.