X0306 4 2019-09-18 0 0001496323 IGM Biosciences, Inc. IGMS 0001788357 Haldor Topsoe Holding A/S HALDOR TOPSOES ALLE 1 KGS. LYNGBY G7 2800 DENMARK 0 0 1 0 Common Stock 2019-09-18 4 P 0 1250000 16.00 A 1250000 D Common Stock 2019-09-20 4 C 0 9039453 0.00 A 10289453 D Series B Preferred Stock 2019-09-20 4 C 0 9039453 0.00 D Common Stock 9039453 0 D Series C Preferred Stock 2019-09-20 4 C 0 2269838 0.00 D Non-Voting Common Stock 2269838 0 D Non-Voting Common Stock 2019-09-20 4 C 0 2269838 0.00 A Common Stock 2269838 2269838 D All shares are held directly by Haldor Topsoe Holding A/S (HTH). Mr. Jakob Haldor Topsoe, Ms. Christina Teng Topsoe, Mr. Martin Topsoe and Mr. Emil Oigaard, members of the board of directors of HTH, may be deemed to share voting and investment power with respect to the shares reported herein and disclaim beneficial ownership of such shares, except to the extent of his or her pecuniary interest therein, if any. Mr. Jakob Haldor Topsoe and Ms. Christina Teng Topsoe are members of the Issuer's board of directors. The Series B Preferred Stock automatically converted into shares of Common Stock on a 1-for-1 basis immediately prior to the closing of the Issuer's initial public offering. The Series B Preferred Stock had no expiration date. The Series C Preferred Stock automatically converted into shares of Non-Voting Common Stock on a 1-for-1 basis, pursuant to an election made by the Reporting Person, immediately prior to the closing of the Issuer's initial public offering, and had no expiration date. Each share of Non-Voting Common Stock is convertible at any time at the option of the Reporting Person into one share of Common Stock (subject to a 4.99% beneficial ownership limitation that may be increased or decreased by the Reporting Person) and has no expiration date. /s/ Misbah Tahir, by power of attorney 2019-09-20