Lyell Immunopharma, Inc. — Director's Dealing 2025

Jul 30, 2025

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: Lyell Immunopharma, Inc. (LYEL)
CIK: 0001806952
Period of Report: 2025-07-25

Reporting Person: ARCH Venture Partners IX, LLC (10% Owner)
Reporting Person: ARCH Venture Partners IX, L.P. (10% Owner)
Reporting Person: ARCH Venture Partners IX Overage, L.P. (10% Owner)
Reporting Person: ARCH Venture Fund IX, L.P. (10% Owner)
Reporting Person: ARCH Venture Fund IX Overage, L.P. (10% Owner)
Reporting Person: CRANDELL KEITH (10% Owner)
Reporting Person: BYBEE CLINTON (10% Owner)
Reporting Person: NELSEN ROBERT (10% Owner)

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock	910317	Indirect
Common Stock	910317	Indirect

Footnotes

F1: These shares are directly held by ARCH Venture Fund IX, L.P. ("ARCH IX"). ARCH Venture Partners IX, L.P. ("GPLP"), as the sole general partner of ARCH IX, may be deemed to beneficially own the shares held by ARCH IX. ARCH Venture Partners IX, LLC ("GPLLC"), as the sole general partner of GPLP, may be deemed to beneficially own the shares held by ARCH IX. As managing directors of GPLLC, each of Keith Crandell, Robert Nelsen and Clinton Bybee (the "ARCH Managing Directors"), may be deemed to beneficially own the shares held by ARCH IX. Each of GPLP, GPLLC and the ARCH Managing Directors disclaims beneficial ownership of the securities reported herein, except to the extent of their pecuniary interest therein, if any.

F2: These shares are directly held by ARCH Venture Fund IX Overage, L.P. ("ARCH Overage"). ARCH Venture Partners IX Overage, L.P. ("Overage GPLP"), as the sole general partner of ARCH Overage, may be deemed to beneficially own the shares held by ARCH Overage. GPLLC, as the sole general partner of Overage GPLP, may be deemed to beneficially own the shares held by ARCH Overage. As managing directors of GPLLC, each of the ARCH Managing Directors may be deemed to beneficially own the shares held by ARCH Overage. Each of Overage GPLP, GPLLC and the ARCH Managing Directors disclaims beneficial ownership of the securities reported herein, except to the extent of their pecuniary interest therein, if any.

F3: The amount of shares reported herein reflects a 1-for-20 reverse stock split that occurred on May 27, 2025.