X0206 3 2025-07-25 0 0001806952 Lyell Immunopharma, Inc. LYEL 0002006772 ARCH Venture Fund XIII, L.P. 8755 W. HIGGINS ROAD, SUITE 1025 CHICAGO IL 60631 0 0 1 0 0002016083 ARCH Venture Partners XIII, L.P. 8755 W. HIGGINS ROAD, SUITE 1025 CHICAGO IL 60631 0 0 1 0 0002016082 ARCH Venture Partners XIII, LLC 8755 W. HIGGINS ROAD, SUITE 1025 CHICAGO IL 60631 0 0 1 0 0001219039 CRANDELL KEITH C/O ARCH VENTURE PARTNERS IX, LLC 8755 W. HIGGINS ROAD, SUITE 1025 CHICAGO IL 60631 0 0 1 0 0001219042 NELSEN ROBERT 8755 W. HIGGINS ROAD, SUITE 1025 CHICAGO IL 60631 0 0 1 0 0001569248 Burow Kristina 8755 W. HIGGINS ROAD,SUITE 1025 CHICAGO IL 60631 0 0 1 0 0001229592 GILLIS STEVEN C/O ARCH VENTURE PARTNERS 8755 WEST HIGGINS ROAD, SUITE 1025 CHICAGO IL 60631 0 0 1 0 0001202769 BERNS PAUL L 8755 W. HIGGINS ROAD, SUITE 1025 CHICAGO IL 60631 0 0 1 0 Common Stock 938438 I By: ARCH Venture Fund XIII, L.P. These shares were purchased on July 25, 2025 pursuant to a securities purchase agreement dated July 24, 2025 at a price per share of $13.32. These shares are directly held by ARCH Venture Fund XIII, L.P. ("ARCH XIII"). ARCH Venture Partners XIII, L.P. ("AVP XIII LP") is the general partner of ARCH XIII. ARCH Venture Partners XIII, LLC ("AVP XIII LLC") is the general partner of AVP XIII LP. Keith Crandell, Robert Nelsen, Kristina Burow, Paul Berns and Steven Gillis are members of the investment committee of AVP XIII LLC (the "AVP XIII LLC Committee Members"). Each of AVP XIII LP and AVP XIII LLC may be deemed to beneficially own the shares held by ARCH XIII, and each of the AVP XIII LLC Committee Members may be deemed to share the power to direct the disposition and vote of the shares held by ARCH XIII. Each of AVP XIII LP, AVP XIII LLC and the AVP XIII LLC Committee Members disclaims beneficial ownership except to the extent of their pecuniary interest therein, if any. ARCH Venture Partners XIII, LLC, By: /s/ Mark McDonnell, as Attorney-in-Fact for Keith Crandell, Managing Director 2025-07-29 ARCH Venture Partners XIII, L.P., By: ARCH Venture Partners XIII, LLC, its General Partner, By: /s/ Mark McDonnell, as Attorney-in-Fact for Keith Crandell, Managing Director 2025-07-29 ARCH Venture Fund XIII, L.P., By: ARCH Venture Partners XIII, L.P., its General Partner, By: ARCH Venture Partners XIII, LLC, its General Partner, By: /s/ Mark McDonnell, as Attorney-in-Fact for Keith Crandell, Managing Director 2025-07-29 Keith Crandell, Managing Director, By: /s/ Mark McDonnell, as Attorney-in-Fact 2025-07-29 Robert Nelsen, Managing Director, By: /s/ Mark McDonnell, as Attorney-in-Fact 2025-07-29 Kristina Burow, Managing Director, By: /s/ Mark McDonnell, as Attorney-in-Fact 2025-07-29 Steven Gillis, Managing Director, By: /s/ Mark McDonnell, as Attorney-in-Fact 2025-07-29 Paul Berns, Managing Director, By: /s/ Mark McDonnell, as Attorney-in-Fact 2025-07-29