X0306 4 2022-05-24 0 0001496323 IGM Biosciences, Inc. IGMS 0001787362 Keyt Bruce C/O IGM BIOSCIENCES, INC. 325 E. MIDDLEFIELD ROAD MOUNTAIN VIEW CA 94043 0 1 0 0 Chief Scientific Officer Common Stock 2022-05-24 4 S 0 939 17.1015 D 39489 D Common Stock 1013 I See footnote These shares were sold to cover tax withholding obligations in connection with the vesting of restricted stock units. This transaction was executed in multiple trades at prices ranging from $16.79 to $17.1269. The price reported above reflects the weighted average sale price. The Reporting Person undertakes to provide upon request by the staff of the Securities and Exchange Commission, the Issuer, or a security holder of the Issuer, full information regarding the number of shares sold at each separate sale price. The shares are held directly by the reporting person's spouse. /s/ Misbah Tahir, by power of attorney 2022-05-26