X0306 4 2014-12-16 0 0001396440 Main Street Capital CORP MAIN 0001236849 JACKSON JOHN EARL 1300 POST OAK BLVD SUITE 800 HOUSTON TX 77056 1 0 0 0 Common Stock 2014-12-16 4 P 0 2500 28.3584 A 11003.406 D The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from 28.199 to 28.407, 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 purchased at each separate price within in the ranges set forth in this footnote. /s/ Jason B. Beauvais as Attorney-in-Fact for John E. Jackson 2014-12-17