X0306 4 2020-03-12 0 0001766368 Mayville Engineering Company, Inc. MEC 0001775975 Butz Todd M 715 SOUTH STREET MAYVILLE WI 53050 0 1 0 0 Chief Financial Officer Common Stock 2020-03-12 4 P 0 5000 4.2261 A 20474 D Common Stock 36967.18 I by ESOP and/or 401(k) Plan Stock Option (right to buy) 7.12 2030-02-27 Common Stock 88029 88029 D Restricted Stock Units 0 Common Stock 35113 35113 D Stock Option (right to buy) 17.00 2029-05-08 Common Stock 39127 39127 D Restricted Stock Units 0 Common Stock 13971 13971 D Restricted Stock Units 0 Common Stock 20589 20589 D The price reported in Column 4 is a weighted average price. The prices actually received ranged from $4.155 to $4.31. The reporting person has provided to the issuer, and will provide to any security holder of the issuer, or the SEC staff, upon request, information regarding the number of shares purchased at each price within the range for all transactions reported in this Form 4 utilizing a weighted average price. The options will vest 50% on each of February 27, 2021 and February 27, 2022. The restricted stock units will vest 50% on each of February 27, 2021 and February 27, 2022. The options will vest 50% on each of May 8, 2020 and May 8, 2021. The restricted stock units will vest 50% on each of May 8, 2020 and May 8, 2021. The restricted stock units will vest 100% on May 8, 2020. /s/ Russell E. Ryba, Attorney-in-Fact for Todd M. Butz 2020-03-13