X0306 4 2020-10-16 0 0001659352 Codiak BioSciences, Inc. CDAK 0001184847 WILLIAMS DOUGLAS E C/O CODIAK BIOSCIENCES, INC. 35 CAMBRIDGEPARK DRIVE, SUITE 500 CAMBRIDGE MA 02140 1 1 0 0 President & CEO Common Stock 2020-10-16 4 C 0 9585 A 9585 D Series C Preferred Stock 2020-10-16 4 C 0 66004 D Common Stock 9585 0 D Each share of Series C Preferred Stock automatically converted into the Issuer's Common Stock on a 1-for-6.8855 basis upon the closing of the Issuer's initial public offering on October 16, 2020 and had no expiration date. The reporting person previously reported shares of common stock into which the Series C Preferred Stock was convertible based on a 1-for-6.8758 conversion ratio estimated at pricing of the Issuer's initial public offering, which reflected a fixed conversion price plus an estimated adjustment based on the issuance of shares in the Issuer's initial public offering. /s/ Yalonda Howze by Power of Attorney for Douglas E. Williams 2020-10-20