Main Street Capital Investor Day Presentation Deck

Follow-on Investment Case Studies Heritage Vet Partners Company Description Initial Transaction Leading provider of veterinary services and animal health products primarily for livestock producers throughout the Midwest U.S. ■ Company sought a financial partner that would assist with its strategic plan and growth initiatives and provide acquisition expertise Acquisition Strategy / Rationale Increased scale to improve buying power and cost saving benefits, strengthening margins and profitability Expand geographic reach Strengthen competitive position Completed nine acquisitions from December 2021 through June 2023 ■ Minority recapitalization with access to additional debt financing for future growth St. Anna Veterinary Clinic CORNERSTONE VETERINARY SERVICES $ in millions ■ Representative Acquisitions ▪ Traditional vet practice evenly split between product and service sales Immediately allowed for increased product sales to existing customers, improving cost of goods sold and profitability ▪ Products-focused practice with pre-existing distributor relationships Increased buying power with distributors, expanded product offering and expanded geographical coverage Initial Capital Invested and Subsequent Investments (¹) ■ $17.0 $6.5 $10.5 $20.6 million, or 121%, of Additional Invested Capital Initial Invested Capital (1) Includes the total debt and equity invested through March 31, 2023, including MAIN and funds managed by the External Investment Manager Main Street Capital Corporation NYSE: MAIN MAIN ST ■Debt CAPITAL CORPORATION Equity $37.6 $7.0 $30.6 Total Invested Capital mainstcapital.com

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