United States securities and exchange commission logo November 9, 2022 Misbah Tahir Chief Financial Officer IGM Biosciences, Inc. 325 E. Middlefield Road Mountain View, CA 94043 Re: IGM Biosciences, Inc. Registration Statement on Form S-3 Filed November 3, 2022 File No. 333-268136 Dear Misbah Tahir: This is to advise you that we have not reviewed and will not review your registration statement. Please refer to Rules 460 and 461 regarding requests for acceleration. We remind you that the company and its management are responsible for the accuracy and adequacy of their disclosures, notwithstanding any review, comments, action or absence of action by the staff. Please contact Jimmy McNamara at 202-551-7349 with any questions. Sincerely, Division of Corporation Finance Office of Life Sciences cc: Jennifer Knapp