Certain Non-Voting Common Stock of IGM Biosciences, Inc. are subject to a Lock-Up Agreement Ending on 28-MAY-2022. These Non-Voting Common Stock will be under lockup for 60 days starting from 29-MAR-2022 to 28-MAY-2022.

Details:
directors and officers (the “Lock-Up Parties”) and the company have agreed that, without the prior written consent of the representatives on behalf of the underwriters, the company and they will not, and will not publicly disclose an intention to, during the period ending 60 days after the date of this prospectus supplement (the “restricted period”) sell, offer to sell, contract to sell or lend any shares of common stock or any options, warrants or rights to acquire shares of common stock or any securities exchangeable or exercisable for or convertible into shares of common stock, or to acquire other securities or rights ultimately exchangeable or exercisable for or convertible into shares of common stock (“Related Securities”), effect any short sale, or establish or increase any “put equivalent position” (as defined in Rule 16a-1(h) under the Exchange Act) or liquidate or decrease any “call equivalent position” (as defined in Rule 16a-1(b) under the Exchange Act) of any common stock or Related Securities, pledge, hypothecate or grant any security interest in any common stock or Related Securities, in any other way transfer or dispose of any common stock or Related Securities, enter into any swap, hedge or similar arrangement or agreement that transfers, in whole or in part, the economic risk of ownership of shares of common stock or Related Securities, regardless of whether any such transaction is to be settled in securities, in cash or otherwise, announce the offering of any shares of common stock or Related Securities, submit or file any registration statement under the Securities Act in respect of any common stock or Related Securities (other than the common stock offered hereby), effect a reverse stock split, recapitalization, share consolidation, reclassification or similar transaction affecting the outstanding common stock or publicly announce any intention to do any of the foregoing.