X0306 4 2022-09-13 0001659352 Codiak BioSciences, Inc. CDAK 0001229592 GILLIS STEVEN C/O ARCH VENTURE PARTNERS 8755 WEST HIGGINS ROAD, SUITE 1025 CHICAGO IL 60631 1 0 0 0 Common Stock 2022-09-13 4 P 0 5000000 A 7503903 I See footnotes Common Stock 10250 D Warrant (Right to Buy) 1.875 2022-09-13 4 P 0 5000000 A 2022-09-13 2027-09-13 Common Stock 5000000 5000000 I See footnotes Shares purchased in a private investment in public equity transaction on September 13, 2022. Accompanying the Common Stock is one Series A Warrant to purchase one share of common stock at an exercise price of $1.875 per share. Shares and warrants held by ARCH Venture Fund VIII, L.P. ("ARCH Fund VIII"). The sole general partner of ARCH Fund VIII is ARCH Venture Partners VIII, L.P. ("ARCH Partners VIII"), which may be deemed to beneficially own the shares and warrants held by ARCH Fund VIII. The sole general partner of ARCH Partners VIII is ARCH Venture Partners VIII, LLC ("ARCH VIII LLC"), which may be deemed to beneficially own the shares and warrants held by ARCH Fund VIII. ARCH Partners VIII and ARCH VIII LLC disclaim beneficial ownership of such shares and warrants, except to the extent of any pecuniary interest therein. The managing directors of ARCH VIII LLC are Keith L. Crandell, Clinton Bybee and Robert Nelsen, and they may be deemed to beneficially own the shares and warrants held by ARCH Fund VIII. Messrs. Crandell, Bybee and Nelsen disclaim beneficial ownership of such shares and warrants, except to the extent of any pecuniary interest therein. The Reporting Person is a managing director at ARCH Partners VIII and owns an interest in ARCH Partners VIII but does not have voting or investment control over the shares and warrants held by ARCH Fund VIII. The Reporting Person disclaims beneficial ownership of such shares and warrants, except to the extent of any pecuniary interest therein. /s/ Mark McDonnell by Power of Attorney for Steven Gillis 2022-09-15