Quarterly report [Sections 13 or 15(d)]

FAIR VALUE HIERARCHY FOR INVESTMENTS???PORTFOLIO COMPOSITION (Tables)

v3.25.2
FAIR VALUE HIERARCHY FOR INVESTMENTS—PORTFOLIO COMPOSITION (Tables)
 6 Months Ended
Jun. 30, 2025
Fair Value Disclosures [Abstract]  
Schedule of Fair Value Measurement Inputs and Valuation Techniques
The following tables provide a summary of the significant unobservable inputs used to fair value Main Street’s Level 3 portfolio investments as of June 30, 2025 and December 31, 2024:
Type of
Investment
Fair Value as of
June 30, 2025
(in thousands)
 Valuation Technique Significant Unobservable Inputs Range (4) Weighted-Average (4)(5) Median (4)
Equity investments $ 1,744,101  Discounted cash flow WACC
9.7% - 22.7%
 14.5  % 15.1  %
Market comparable / Enterprise value EBITDA multiple (1) (3)
5.0x - 9.0x (2)
 7.2x 6.5x
Debt investments $ 3,301,875  Discounted cash flow Risk adjusted discount rate (6)
8.3% - 18.6% (2)
 12.3  % 12.1  %
Expected principal recovery percentage
0.0% - 500.0%
 98.8  % 100.0  %
Debt investments $ 25,537  Market approach Third-party quote
14.5 - 99.7
 81.2 55.0
Total Level 3 investments $ 5,071,513 
___________________________
(1)EBITDA may include proforma adjustments and/or other add-backs based on specific circumstances related to each investment.
(2)Range excludes outliers that are greater than one standard deviation from the mean. Including these outliers, the range for EBITDA multiple is 2.0x - 16.0x and the range for risk adjusted discount rate is 5.0% - 36.0%.
(3)The fair value of the equity investment in the External Investment Manager is based on a fee multiple of 8.7x. The fair value determination is based on a discounted, blended multiple based on the multiples for similar businesses in active markets and actual multiples used in private transactions.
(4)Does not include investments for which the valuation technique does not include the use of the applicable fair value input.
(5)Weighted-average is calculated for each significant unobservable input based on the applicable security’s fair value.
(6)Discount rate includes the effect of the standard SOFR base rate, as applicable.
Type of Investment
Fair Value as of December 31, 2024
(in thousands)
 Valuation Technique Significant Unobservable Inputs Range (4) Weighted-Average (4)(5) Median (4)
Equity investments $ 1,654,304  Discounted cash flow WACC
9.4% - 22.5%
 14.5  % 15.1  %
Market comparable / Enterprise value EBITDA multiple (1) (3)
4.8x - 8.9x (2)
 7.0x 6.5x
Debt investments $ 3,174,745  Discounted cash flow Risk adjusted discount rate (6)
8.5% - 19.1% (2)
 12.6  % 12.2  %
Expected principal recovery percentage
0.0% - 100.0%
 99.5  % 100.0  %
Debt investments $ 103,620  Market approach Third-party quote
21.0 - 100.7
 90.5 84.5
Total Level 3 investments $ 4,932,669 
___________________________
(1)EBITDA may include proforma adjustments and/or other add-backs based on specific circumstances related to each investment.
(2)Range excludes outliers that are greater than one standard deviation from the mean. Including these outliers, the range for EBITDA multiple is 2.0x - 17.0x and the range for risk adjusted discount rate is 5.0% - 38.3%.
(3)The fair value of the equity investment in the External Investment Manager is based on a fee multiple of 8.5x. The fair value determination is based on a discounted, blended multiple based on the multiples for similar businesses in active markets and actual multiples used in private transactions.
(4)Does not include investments for which the valuation technique does not include the use of the applicable fair value input.
(5)Weighted-average is calculated for each significant unobservable input based on the applicable security’s fair value.
(6)Discount rate includes the effect of the standard SOFR base rate, as applicable.
Schedule of Changes in Fair Value of Main Street’s Level 3 Portfolio Investments
The following tables provide a summary of changes in fair value of Main Street’s Level 3 portfolio investments for the six months ended June 30, 2025 and 2024 (amounts in thousands):
Type of Investment
Fair Value
as of
December 31, 2024
 Transfers Out of Level 3 Hierarchy Redemptions/ Repayments New Investments Net Changes from Unrealized to Realized Net Unrealized Appreciation (Depreciation) Other (1)
Fair Value
as of
June 30, 2025
Debt $ 3,278,365  $ —  $ (514,216) $ 575,433  $ 38,415  $ (19,812) $ (30,773) $ 3,327,412 
Equity 1,637,181  (16,810) (30,679) 80,309  (65,185) 83,449  30,773  1,719,038 
Equity Warrant 17,123  —  —  —  —  7,940  —  25,063 
$ 4,932,669  $ (16,810) $ (544,895) $ 655,742  $ (26,770) $ 71,577  $ —  $ 5,071,513 
___________________________
(1)Includes the impact of non-cash conversions. These transactions represent non-cash investing activities. See additional cash flow information in the Consolidated Statements of Cash Flows.
Type of Investment
Fair Value
as of
December 31, 2023
 Transfers Into Level 3 Hierarchy Redemptions/ Repayments New Investments Net Changes from Unrealized to Realized Net Unrealized Appreciation (Depreciation) Other (1)
Fair Value
as of
June 30, 2024
Debt $ 2,883,917  $ —  $ (406,233) $ 753,750  $ 7,468  $ (19,162) $ 18,859  $ 3,238,599 
Equity 1,395,744  —  (28,445) 65,122  (960) 75,391  (18,859) 1,487,993 
Equity Warrant 6,610  —  —  3,920  —  389  —  10,919 
$ 4,286,271  $ —  $ (434,678) $ 822,792  $ 6,508  $ 56,618  $ —  $ 4,737,511 
___________________________
(1)Includes the impact of non-cash conversions. These transactions represent non-cash investing activities. See additional cash flow information in the Consolidated Statements of Cash Flows.
Schedule of Portfolio Investments by Level in the Fair Value Hierarchy
As of June 30, 2025 and December 31, 2024, Main Street’s investments at fair value were categorized as follows in the fair value hierarchy for ASC 820 purposes:
Fair Value Measurements
(in thousands)
As of June 30, 2025
 Fair Value Quoted Prices in
Active Markets for
Identical Assets
(Level 1)		 Significant Other
Observable Inputs
(Level 2)		 Significant
Unobservable
Inputs
(Level 3)
LMM portfolio investments $ 2,668,844  $ —  $ —  $ 2,668,844 
Private Loan portfolio investments 1,920,257  —  —  1,920,257 
Middle Market portfolio investments 108,705  —  —  108,705 
Other Portfolio investments 122,664  21,557  —  101,107 
External Investment Manager 272,600  —  —  272,600 
Total investments $ 5,093,070  $ 21,557  $ —  $ 5,071,513 
Fair Value Measurements
(in thousands)
As of December 31, 2024
 Fair Value Quoted Prices in
Active Markets for
Identical Assets
(Level 1)		 Significant Other
Observable Inputs
(Level 2)		 Significant
Unobservable
Inputs
(Level 3)
LMM portfolio investments $ 2,502,872  $ —  $ —  $ 2,502,872 
Private Loan portfolio investments 1,904,324  —  —  1,904,324 
Middle Market portfolio investments 155,329  —  —  155,329 
Other Portfolio investments 124,144  —  —  124,144 
External Investment Manager 246,000  —  —  246,000 
Total investments $ 4,932,669  $ —  $ —  $ 4,932,669 
Schedule of Investment Holdings
The following tables provide a summary of Main Street’s investments in the LMM and Private Loan portfolios as of June 30, 2025 and December 31, 2024 (this information excludes Middle Market, Other Portfolio investments and the External Investment Manager, which are discussed further below).
As of June 30, 2025
LMM (a) Private Loan
(dollars in millions)
Number of portfolio companies 88  87 
Fair value $ 2,668.8  $ 1,920.3 
Cost $ 2,105.0  $ 1,958.0 
Debt investments as a % of portfolio (at cost) 70.1  % 94.7  %
Equity investments as a % of portfolio (at cost) 29.9  % 5.3  %
% of debt investments at cost secured by first priority lien 99.3  % 99.9  %
Weighted-average annual effective yield (b) 12.8  % 11.4  %
Average EBITDA (c) $ 10.4  $ 32.5 
___________________________
(a)As of June 30, 2025, Main Street had equity ownership in all of its LMM portfolio companies, and the average fully diluted equity ownership in those portfolio companies was 38%.
(b)The weighted-average annual effective yields were computed using the effective interest rates for all debt investments as of June 30, 2025, including amortization of deferred debt origination fees and accretion of original issue discount but excluding fees payable upon repayment of the debt instruments and any debt investments on non-accrual status, and are weighted based upon the principal amount of each applicable debt investment as of June 30, 2025. The weighted-average annual effective yield on Main Street’s debt portfolio as of June 30, 2025, including debt investments on non-accrual status, was 12.1% for its LMM portfolio and 10.0% for its Private Loan portfolio. The weighted-average annual effective yield is not reflective of what an investor in shares of Main Street’s common stock will realize on its investment because it does not reflect changes in the market value of Main Street’s stock, Main Street’s utilization of debt capital in its capital structure, Main Street’s expenses or any sales load paid by an investor.
(c)The average EBITDA is calculated using a simple average for the LMM portfolio and a weighted-average for the Private Loan portfolio. These calculations exclude certain portfolio companies, including six LMM portfolio companies and six Private Loan portfolio companies, as EBITDA is not a meaningful valuation metric for Main Street’s investments in these portfolio companies, and those portfolio companies whose primary purpose is to own real estate and those portfolio companies whose primary operations have ceased and only residual value remains.
As of December 31, 2024
LMM (a) Private Loan
(dollars in millions)
Number of portfolio companies 84  91 
Fair value $ 2,502.9  $ 1,904.3 
Cost $ 1,937.8  $ 1,952.5 
Debt investments as a % of portfolio (at cost) 70.8  % 95.4  %
Equity investments as a % of portfolio (at cost) 29.2  % 4.6  %
% of debt investments at cost secured by first priority lien 99.2  % 99.9  %
Weighted-average annual effective yield (b) 12.8  % 11.8  %
Average EBITDA (c) $ 10.2  $ 30.5 
___________________________
(a)As of December 31, 2024, Main Street had equity ownership in all of its LMM portfolio companies, and the average fully diluted equity ownership in those portfolio companies was 38%.
(b)The weighted-average annual effective yields were computed using the effective interest rates for all debt investments as of December 31, 2024, including amortization of deferred debt origination fees and accretion of original issue discount but excluding fees payable upon repayment of the debt instruments and any debt investments on non-accrual status, and are weighted based upon the principal amount of each applicable debt investment as of December 31, 2024. The weighted-average annual effective yield on Main Street’s debt portfolio as of December 31, 2024, including debt investments on non-accrual status, was 12.3% for its LMM portfolio and 11.5% for its Private Loan portfolio. The weighted-average annual effective yield is not reflective of what an investor in shares of Main Street’s common stock will realize on its investment because it does not reflect changes in the market value of Main Street’s stock, Main Street’s utilization of debt capital in its capital structure, Main Street’s expenses or any sales load paid by an investor.
(c)The average EBITDA is calculated using a simple average for the LMM portfolio and a weighted-average for the Private Loan portfolio. These calculations exclude certain portfolio companies, including five LMM portfolio companies and five Private Loan portfolio companies, as EBITDA is not a meaningful valuation metric for Main Street’s investments in these portfolio companies, and those portfolio companies whose primary purpose is to own real estate and those portfolio companies whose primary operations have ceased and only residual value remains.
The following tables summarize the composition of Main Street’s total combined LMM, Private Loan and Middle Market portfolio investments at cost and fair value by type of investment as a percentage of the total combined LMM, Private Loan and Middle Market portfolio investments, as of June 30, 2025 and December 31, 2024 (this information excludes Other Portfolio investments and the External Investment Manager, which are discussed above).
Cost: June 30, 2025 December 31, 2024
First lien debt 81.5  % 82.9  %
Equity 17.9  16.4 
Second lien debt 0.1  0.2 
Equity warrants 0.3  0.3 
Other 0.2  0.2 
100.0  % 100.0  %
Fair Value: June 30, 2025 December 31, 2024
First lien debt 70.5  % 71.4  %
Equity 28.7  27.8 
Second lien debt 0.1  0.2 
Equity warrants 0.5  0.4 
Other 0.2  0.2 
100.0  % 100.0  %
The following tables summarize the composition of Main Street’s total combined LMM, Private Loan and Middle Market portfolio investments by geographic region of the United States and other countries at cost and fair value as a percentage of the total combined LMM, Private Loan and Middle Market portfolio investments, as of June 30, 2025 and December 31, 2024 (this information excludes Other Portfolio investments and the External Investment Manager). The geographic composition is determined by the location of the corporate headquarters of the portfolio company.
Cost: June 30, 2025 December 31, 2024
West 26.0  % 25.1  %
Midwest 21.2  22.7 
Northeast 19.6  21.2 
Southwest 19.5  16.7 
Southeast 11.1  11.6 
Canada 1.2  1.3 
Other Non-United States 1.4  1.4 
100.0  % 100.0  %
Fair Value: June 30, 2025 December 31, 2024
West 25.2  % 24.1  %
Southwest 23.1  20.1 
Midwest 22.4  24.2 
Northeast 17.0  19.4 
Southeast 9.9  9.7 
Canada 1.1  1.2 
Other Non-United States 1.3  1.3 
100.0  % 100.0  %
The following tables summarize the composition of Main Street’s total combined LMM, Private Loan and Middle Market portfolio investments by industry at cost and fair value as of June 30, 2025 and December 31, 2024 (this information excludes Other Portfolio investments and the External Investment Manager).
Cost: June 30, 2025 December 31, 2024
Machinery 8.9  % 9.2  %
Internet Software & Services 6.7  7.1 
Commercial Services & Supplies 6.5  5.5 
Electrical Equipment 6.0  3.9 
Distributors 5.7  4.0 
Professional Services 5.3  5.4 
Construction & Engineering 4.4  3.8 
Diversified Consumer Services 4.0  4.3 
IT Services 4.0  4.1 
Auto Components 3.7  4.0 
Containers & Packaging 3.7  3.8 
Health Care Providers & Services 3.3  4.3 
Textiles, Apparel & Luxury Goods 2.7  2.8 
Tobacco 2.7  2.8 
Energy Equipment & Services 2.6  2.8 
Leisure Equipment & Products 2.3  2.4 
Software 2.3  2.2 
Computers & Peripherals 2.2  2.8 
Communications Equipment 2.0  2.1 
Specialty Retail 2.0  2.0 
Media 1.6  1.7 
Food Products 1.5  1.6 
Chemicals 1.3  1.3 
Food & Staples Retailing 1.3  1.6 
Hotels, Restaurants & Leisure 1.3  1.3 
Oil, Gas & Consumable Fuels 1.3  — 
Aerospace & Defense 1.2  1.6 
Internet & Catalog Retail 1.1  1.1 
Health Care Equipment & Supplies 0.9  1.1 
Diversified Financial Services 0.8  1.4 
Building Products 0.4  1.5 
Other (1) 6.3  6.5 
100.0  % 100.0  %
___________________________
(1)Includes various industries with each industry individually less than 1.0% of the total combined LMM, Private Loan and Middle Market portfolio investments at each date.
Fair Value: June 30, 2025 December 31, 2024
Machinery 11.0  % 11.0  %
Commercial Services & Supplies 5.9  4.8 
Distributors 5.8  4.2 
Diversified Consumer Services 5.8  6.0 
Electrical Equipment 5.6  3.7 
Internet Software & Services 5.4  5.9 
Professional Services 5.3  5.2 
Construction & Engineering 4.7  4.3 
Computers & Peripherals 4.0  4.6 
Containers & Packaging 3.7  3.8 
IT Services 3.4  3.7 
Auto Components 3.3  3.6 
Health Care Providers & Services 3.1  4.5 
Tobacco 2.8  2.9 
Energy Equipment & Services 2.7  2.9 
Specialty Retail 2.5  2.5 
Software 2.4  2.3 
Textiles, Apparel & Luxury Goods 1.9  1.9 
Communications Equipment 1.8  1.4 
Leisure Equipment & Products 1.7  1.7 
Media 1.7  1.9 
Chemicals 1.2  1.2 
Food Products 1.2  1.5 
Oil, Gas & Consumable Fuels 1.2  — 
Aerospace & Defense 1.1  1.6 
Food & Staples Retailing 1.1  1.2 
Internet & Catalog Retail 0.9  1.0 
Diversified Financial Services 0.7  1.3 
Building Products 0.4  1.4 
Other (1) 7.7  8.0 
100.0  % 100.0  %
___________________________
(1)Includes various industries with each industry individually less than 1.0% of the total combined LMM, Private Loan and Middle Market portfolio investments at each date.