X0508 4 2025-12-11 0001766368 Mayville Engineering Company, Inc. MEC 0001342891 Fisher Steven L 135 SOUTH 84TH STREET SUITE 300 MILWAUKEE WI 53214 true false Common Stock 2025-12-11 4 S 0 5000 19.08 D 35482 D Common Stock 2025-12-11 4 S 0 5000 19.14 D 30482 D Director Restricted Stock Units 0 Common Stock 10331 10331 D Director Deferred Stock Units 0 Common Stock 39900 39900 D The restricted stock units will vest 100% at the earlier of one year or the next annual shareholder meeting. The balance includes vested RSUs that were deferred by the reporting person, which will be settled upon the reporting person's retirement or separation from the company. /s/ Russell E. Ryba, Attorney-in-Fact for Steven L. Fisher 2025-12-15