X0609 4 2026-08-21 0001396440 Main Street Capital CORP MAIN 0001596070 Morris Jesse E false 1300 POST OAK BLVD, 8TH FLOOR HOUSTON TX 77056 false true false false EVP AND COO 0 Common Stock 2026-08-21 4 S 0 35000 58.55 D 232568.4258 D The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $58.33 to $58.74, inclusive. The reporting person undertakes to provide to Main Street Capital Corporation, any of its security holders or the staff of the SEC, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. /s/ Jason B. Beauvais, Attorney-in-Fact 2026-08-24