Main Street Capital Investor Day Presentation Deck

5 Year Strategic Overview - Continued Income Growth Maintain growth in DNII per share through investment portfolio growth and leverage of efficient cost structure Main Street Capital Corporation MAIN ST Continue to grow Total Investment Income primarily through investment portfolio growth CAPITAL CORPORATION • Grow total investment income (at a minimum) in line with growth in total investment portfolio Supplement growth in Total Investment Income from investment portfolio with growth in Net Investment Income contribution from Asset Management Business (AMB) • Grow assets under management and recurring base fee income Continue receiving meaningful incentive fees ● Continue to leverage efficient internally managed cost structure to grow Distributable Net Investment Income (DNII) per share Maintain industry leading operating cost structure with operating expenses, excluding interest expense, as a percentage of total assets at or below 1.75% Maintain efficiency ratio of less than 22.5% The above ratios might increase slightly as growth of AMB is realized (since AMB will not grow MAIN's assets), but AMB should be meaningfully accretive to MAIN's DNII per share (no interest expense, investment capital or proportionate significant personnel increases) NYSE: MAIN Maintain strong total investment income to DNII conversion (i.e. operating margins) through efficient operating costs mainstcapital.com

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