X0306 4 2020-10-16 0 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 2020-10-16 4 C 0 1784572 A 1848535 I See Footnotes Common Stock 2020-10-16 4 C 0 420368 A 2268903 I See Footnotes Common Stock 2020-10-16 4 P 0 235000 15.00 A 2503903 I See Footnotes Series A Preferred Stock 2020-10-16 4 C 0 13950000 D Common Stock 1784572 0 I See Footnotes Series B Preferred Stock 2020-10-16 4 C 0 3000000 D Common Stock 420368 0 I See Footnotes Each share of Series A Preferred Stock automatically converted into the Issuer's Common Stock on a 1-for-7.8170 basis upon the closing of the Issuer's initial public offering on October 16, 2020 and had no expiration date. Shares 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 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 held by ARCH Fund VIII. ARCH Partners VIII and ARCH VIII LLC disclaim beneficial ownership of such shares, 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 held by ARCH Fund VIII. Messrs. Crandell, Bybee and Nelsen disclaim beneficial ownership of such shares, 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 held by ARCH Fund VIII. The Reporting Person disclaims beneficial ownership of such shares, except to the extent of any pecuniary interest therein. Each share of Series B Preferred Stock automatically converted into the Issuer's Common Stock on a 1-for-7.1366 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 B Preferred Stock was convertible based on a 1-for-7.1295 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 Steven Gillis 2020-10-20