Main Street Investor Presentation

Disclaimers MAINST CAPITAL CORPORATION Main Street Capital Corporation (MAIN) cautions that statements in this presentation that are forward-looking, and provide other than historical information, involve risks and uncertainties that may impact our future results of operations. The forward-looking statements in this presentation are based on current conditions as of August 7, 2020, and include, but are not limited to, statements regarding our goals, beliefs, strategies, future operating results and cash flows, operating expenses, investment originations and performance, available capital, payment and the tax attributes of future dividends and shareholder returns. Although our management believes that the expectations reflected in any forward-looking statements are reasonable, we can give no assurance that those expectations will prove to have been correct. Those statements are made based on various underlying assumptions and are subject to numerous uncertainties and risks, including, without limitation: our continued effectiveness in raising, investing and managing capital; adverse changes in the economy generally or in the industries in which our portfolio companies operate; the potential impacts of the COVID-19 pandemic on our and our portfolio companies' business and operations, liquidity and access to capital, and on the U.S. and global economies, including public health requirements in response to the pandemic; changes in laws and regulations or business, political and/or regulatory conditions that may adversely impact our operations or the operations of our portfolio companies; the operating and financial performance of our portfolio companies and their access to capital; retention of key investment personnel; competitive factors; and such other factors described under the captions "Cautionary Statement Concerning Forward-Looking Statements," Management's Discussion and Analysis of Financial Condition and Results of Operations" and "Risk Factors" included in our filings with the Securities and Exchange Commission (www.sec.gov), including our most recent annual report on Form 10-K and quarterly report on Form 10-Q. We undertake no obligation to update the information contained herein to reflect subsequently occurring events or circumstances, except as required by applicable securities laws and regulations. MAIN has filed a registration statement (induding a prospectus and prospectus supplements) with the SEC for any offering to which this communication may relate and may file one or more supplements to the prospectus in the future. Before you invest in any of MAIN's securities, you should read the registration statement and the applicable prospectus and prospectus supplement(s) in order to fully understand all of the implications and risks of an offering of MAIN's securities. You should also read other documents MAIN has filed with the SEC for more complete information about MAIN and its securities offerings. You may get these documents for free by visiting EDGAR on the SEC website at www.sec.gov. Alternatively, MAIN will arrange to send you any applicable prospectus and prospectus supplement if you request such materials by calling us at (713) 350-6000. These materials are also made available, free of charge, on our website at www.mainstcapital.com. Information contained on our website is not incorporated by reference into this communication. The summary descriptions and other information included herein are intended only for informational purposes and convenient reference. The information contained herein is not intended to provide, and should not be relied upon for, accounting. legal or tax advice or investment recommendations. Before making an investment decision with respect to MAIN, investors are advised to carefully review an applicable prospectus to review the risk factors described or incorporated by reference therein, and to consult with their tax, financial, investment and legal advisors. These materials do not purport to be complete, and are qualified in their entirety by reference to the more detailed disdosures contained in an applicable prospectus and MAIN's related documentation. Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 2

View entire presentation