X0306 4 2021-05-06 0 0001374535 Altra Industrial Motion Corp. AIMC 0001383274 Christenson Carl R C/O ALTRA INDUSTRIAL MOTION CORP. 300 GRANITE STREET SUITE 201 BRAINTREE MA 02184 1 1 0 0 Chairman and CEO Common Stock, par value $0.001 2021-05-06 4 M 0 41273 30.65 A 90946 D Common Stock, par value $0.001 2021-05-06 4 S 0 41273 65.00 D 49673 D Common Stock, par value $0.001 2021-05-07 4 M 0 20000 30.65 A 69673 D Common Stock, par value $0.001 2021-05-07 4 S 0 20000 67.00 D 49673 D Common Stock, par value $0.001 127438 I By Trust Common Stock, par value $0.001 300 I By Children, see footnote Stock Option 30.65 2021-05-06 4 M 0 41273 30.65 D 2029-02-12 Common Stock, par value $0.001 41273 81274 D Stock Option 30.65 2021-05-07 4 M 0 20000 30.65 D 2029-02-12 Common Stock, par value $0.001 20000 61274 D The shares are held in a trust for which Mr. Christenson serves as trustee. Shares are held by Reporting Persons children. The option grant has a graded vesting schedule, of which 30,636 and 30,637 became exercisable on August 15, 2019 and August 15, 2020, respectively. Todd Patriacca, Attorney-in-fact 2021-05-10