[Form 4] Lyell Immunopharma, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Seely Lynn, who serves as President and CEO and a director of Lyell Immunopharma, reported the issuance and a subsequent sale of company common stock. Per performance-based restricted stock units granted on February 9, 2024, 40,000 shares were recorded as issued on 08/20/2025, with 20,000 shares issued immediately upon certification of performance and the remaining 20,000 shares scheduled for issuance on 08/20/2026 subject to continued service. The next day, 7,257 shares were sold automatically to cover tax withholding at a weighted average price of $10.544 (sales ranged $10.49 to $10.64). After these transactions the reporting person beneficially owned 67,571 shares.

Positive

• Performance criteria met leading to issuance of equity reflects achievement of goals certified by the compensation committee
• Transparent disclosure of both the issuance, the tax-withholding sale, and the sale price range ( $10.49 to $10.64 )

Negative

• Additional shares to be issued (20,000 on 08/20/2026) create potential future dilution for existing shareholders
• Automatic sale of 7,257 shares reduced the reporting person’s immediate holdings and was executed within a narrow price range

Insights

Securities Analyst

TL;DR: Routine insider vesting and tax-withholding sale; limited immediate market impact.

The filing documents the vesting of performance-based restricted stock units and an automatic sale to satisfy tax withholding. The issuance of 40,000 shares increases the insider's holdings in line with prior compensation awards, while the 7,257-share disposition was a non-discretionary sale to cover taxes at a weighted average of $10.544. These actions are standard for equity compensation programs and do not, on their face, signal a change in corporate strategy or material disposition of holdings beyond withholding.

Corporate Governance Expert

TL;DR: Compensation committee certified performance; disclosure aligns with Section 16 reporting requirements.

The form shows the compensation committee certified achievement of performance criteria triggering partial issuance of performance RSUs, with the remaining tranche conditioned on future service. The clear explanation of the vesting schedule and tax-withholding sale reflects appropriate disclosure practices. The scheduled future issuance of 20,000 shares remains subject to service through the specified date, which is disclosed in the filing.

SEC Form 4

FORM 4

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
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Seely Lynn

(Last) (First) (Middle)

C/O LYELL IMMUNOPHARMA, INC.

201 HASKINS WAY

(Street)

SOUTH SAN FRANCISCO CA 94080

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Lyell Immunopharma, Inc. [ LYEL ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	President and CEO

3. Date of Earliest Transaction (Month/Day/Year)
08/20/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	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	08/20/2025		A		40,000(1)	A	$0	74,828	D
Common Stock	08/21/2025		S		7,257(2)	D	$10.544(3)	67,571	D

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 (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	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 (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (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: 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

Explanation of Responses:

1. Pursuant to performance-based restricted stock units granted to the reporting person on February 9, 2024, 20,000 shares were issued on the Transaction Date upon the achievement of certain performance criteria certified by the compensation committee of the Issuer's board of directors on the Transaction Date and 20,000 shares will be issued on August 20, 2026, subject to the reporting person providing service through such date.

2. Shares automatically sold to cover tax withholding obligation from settlement of vested restricted stock units.

3. The price reported above reflects the weighted average price of the shares sold. The sale price ranged from $10.49 to $10.64 per share. Upon request from the SEC staff, the Issuer, or a security holder of the Issuer, the Reporting Person will provide full information regarding the number of shares sold at each separate price within the range set forth in this Form 4.

	/s/ Charles W. Newton, Attorney-in-Fact	08/22/2025
	** Signature of Reporting Person	Date
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).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
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FAQ

What transactions did Seely Lynn report on Form 4 for LYEL?

The report shows 40,000 shares issued upon vesting of performance-based RSUs and an automatic sale of 7,257 shares to cover tax withholding.

How many LYEL shares will still be issued in the future to Seely Lynn?

20,000 shares remain scheduled for issuance on 08/20/2026, subject to the reporting person providing service through that date.

At what price were the 7,257 LYEL shares sold to cover taxes?

The weighted average sale price reported was $10.544, with individual sale prices ranging from $10.49 to $10.64.

How many LYEL shares does Seely Lynn beneficially own after these transactions?

Following the reported transactions the filing shows the reporting person beneficially owned 67,571 shares.

What was the basis for the 40,000 LYEL shares issuance?

The shares were issued pursuant to performance-based restricted stock units granted on February 9, 2024, and certified by the compensation committee upon achievement of performance criteria.