Sec Form 4 Filing - ARCH Venture Partners IX, LLC @ Lyell Immunopharma, Inc. - 2021-06-21

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person ARCH Venture Partners IX, LLC 2. Issuer Name and Ticker or Trading Symbol Lyell Immunopharma, Inc. [ LYEL] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 8755 W. HIGGINS ROAD, SUITE 1025 3. Date of Earliest Transaction (MM/DD/YY) 06/21/2021 (Street) CHICAGO, IL60631 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 06/21/2021 C 18,206,358 A 18,206,358 I ARCH Venture Fund IX, L.P. ( 2 ) Common Stock 06/21/2021 C 18,206,358 A 18,206,358 I ARCH Venture Fund IX Overage, L.P. ( 2 )

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Series A Convertible Preferred Stock ( 1 ) 06/21/2021 C 17,771,216 ( 1 ) ( 1 ) Common Stock 17,771,216 $ 0 0 I ARCH Venture Fund IX, L.P. ( 2 ) Series A Convertible Preferred Stock ( 1 ) 06/21/2021 C 17,771,216 ( 1 ) ( 1 ) Common Stock 17,771,216 $ 0 0 I ARCH Venture Fund IX Overage, L.P. ( 2 ) series C Convertible Preferred Stock ( 1 ) 06/21/2021 C 435,142 ( 1 ) ( 1 ) Common Stock 435,142 $ 0 0 I ARCH Venture Fund IX, L.P. ( 2 ) Series C Convertible Preferred Stock ( 1 ) 06/21/2021 C 435,142 ( 1 ) ( 1 ) Common Stock 435,142 $ 0 0 I ARCH Venture Fund IX Overage, L.P. ( 2 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other ARCH Venture Partners IX, LLC 8755 W. HIGGINS ROAD SUITE 1025 CHICAGO, IL60631 X ARCH Venture Fund IX Overage, L.P. 8755 W. HIGGINS ROAD SUITE 1025 CHICAGO, IL60631 X ARCH Venture Fund IX, L.P. 8755 W. HIGGINS ROAD SUITE 1025 CHICAGO, IL60631 X ARCH Venture Partners IX Overage, L.P. 8755 W. HIGGINS ROAD SUITE 1025 CHICAGO, IL60631 X ARCH Venture Partners IX, L.P. 8755 W. HIGGINS ROAD SUITE 1025 CHICAGO, IL60631 X CRANDELL KEITH 8755 W. HIGGINS ROAD SUITE 1025 CHICAGO, IL60631 X BYBEE CLINTON 8755 W. HIGGINS ROAD SUITE 1025 CHICAGO, IL60631 X Signatures /s/ ARCH Venture Fund IX, L.P., By: ARCH Venture Partners IX, L.P., its General Partner, By: ARCH Venture Partners IX, LLC, its General Partner, By: Mark McDonnell,attorney in-fact 06/21/2021 Signature of Reporting Person Date /s/ ARCH Venture Fund IX Overage, L.P., By: ARCH Venture Partners IX Overage, L.P., its General Partner, By: ARCH Venture Partners IX, LLC, its General Partner, By:Mark McDonnell, attorney in-fact 06/21/2021 Signature of Reporting Person Date /s/ ARCH Venture Partners IX, L.P., By: ARCH Venture Partners IX, LLC, its General Partner, By: Mark McDonnell, attorney in-fact 06/21/2021 Signature of Reporting Person Date /s/ ARCH Venture Partners IX Overage, L.P., By: ARCH Venture Partners IX, LLC, its General Partner, By: Mark McDonnell, attorney in-fact 06/21/2021 Signature of Reporting Person Date /s/ ARCH Venture Partners IX, LLC, By: Mark McDonnell, attorney in-fact 06/21/2021 Signature of Reporting Person Date /s/ Keith Crandell, By: Mark McDonnell, attorney in-fact 06/21/2021 Signature of Reporting Person Date /s/ Clinton Bybee, By: Mark McDonnell, attorney in-fact 06/21/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The Issuer's Series A Convertible Preferred Stock and Series C Convertible Preferred Stock converted into Common Stock on a 1-for-1 basis and had no expiration date. ( 2 )ARCH Venture Partners IX, L.P. (AVP IX LP) is the sole general partner of ARCH Venture Fund IX, L.P. (ARCH IX). ARCH Venture Partners IX Overage, L.P. (AVP IX Overage LP) is the sole general partner of ARCH Venture Fund IX Overage, L.P. (ARCH IX Overage). ARCH Venture Partners IX, LLC (AVP IX LLC) is the sole general partner of each of AVP IX LP and AVP IX Overage LP. Keith Crandell and Clinton Bybee are managing directors of AVP IX LLC (the AVP IX MDs). 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 each of the AVP IX MDs 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, AVP IX LLC, and the AVP IX MDs each disclaim beneficial ownership except to the extent of any pecuniary interest therein.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

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