X0206 3 2021-06-16 0 0001806952 Lyell Immunopharma, Inc. LYEL 0001219042 NELSEN ROBERT 8755 WEST HIGGINS ROAD, SUITE 1025 CHICAGO IL 60631 1 0 1 0 Series A Convertible Preferred Stock 1.8288 Common Stock 17771216 I ARCH Venture Fund IX, L.P. Series A Convertible Preferred Stock 1.8288 Common Stock 17771216 I ARCH Venture Fund IX Overage, L.P. Series C Convertible Preferred Stock 11.4905 Common Stock 435142 I ARCH Venture Fund IX, L.P. Series C Convertible Preferred Stock 11.4905 Common Stock 435142 I ARCH Venture Fund IX Overage, L.P. The Series A Convertible Preferred Stock is convertible at any time, at the holder's election, has no expiration date, and will automatically convert to shares of the Issuer's Common Stock immediately prior to the closing of the Issuer's initial public offering on a 1-for-1 basis. These shares are directly held by ARCH Venture Fund IX, L.P. (ARCH IX). ARCH Venture Partners IX, L.P. (AVP IX LP) is the sole general partner of ARCH IX. ARCH Venture Partners IX, LLC (AVP IX LLC) is the sole general partner of each of AVP IX LP and AVP IX Overage LP. The Reporting Person is a managing director of AVP IX LLC ("AVP IX MD"). AVP IX LP and AVP IX Overage LP may be deemed to beneficially own the shares held by ARCH IX and ARCH IX Overage, respectively, AVP IX LLC may be deemed to beneficially own the shares held by ARCH IX and ARCH IX Overage, and the AVP IX MD may be deemed to share the power to direct the disposition and vote of the shares held by ARCH IX and ARCH IX Overage. AVP IX LP, AVP IX Overage LP and AVP IX LLC each disclaim beneficial ownership except to the extent of any pecuniary interest therein. The Reporting Person is an AVP IX MD and may be deemed to beneficially own the shares held by ARCH IX and ARCH IX Overage. The Reporting Person disclaims beneficial ownership of such shares except to the extent of his pecuniary interest therein, if any. These shares are directly held by ARCH Venture Fund IX Overage, L.P. (ARCH IX Overage). ARCH Venture Partners IX Overage, L.P. (AVP IX Overage LP) is the sole general partner of ARCH IX Overage. The Series C Convertible Preferred Stock is convertible at any time, at the holder's election, has no expiration date, and will automatically convert to shares of the Issuer's Common Stock immediately prior to the closing of the Issuer's initial public offering on a 1-for-1 basis. /s/ Heather Turner, Attorney-in-Fact for Robert Nelsen 2021-06-16