Main Street Capital Fixed Income Presentation Deck

Investment Portfolio - By Type of Investment (¹) Other Portfolio (2) Equity, 2.8%, $116.1m Total Investment Portfolio $4.2 billion Equity, 26.5%, $1.1b Debt Investments, 70.7%, $2.9b (1) Fair value as of March 31, 2023 (2) Other portfolio investments, as described in MAIN's SEC filings Main Street Capital Corporation NYSE: MAIN Total Debt Investments $2.9 billion First Lien Debt, 99.2%, $2.9b MAIN ST CAPITAL CORPORATION Junior Debt, 0.8%, $24.8m mainstcapital.com Page 5

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