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

Rhea-AI Filing Summary

Lyell Immunopharma insider activity by Gary K. Lee: The company's Chief Scientific Officer received 8,000 shares on 08/20/2025 from performance-based restricted stock units, 4,000 of which vested upon certification of performance and 4,000 remain contingent on continued service through 08/20/2026. Following that issuance the reporting person beneficially owned 16,957 shares. On 08/21/2025 the reporting person sold 1,453 shares to satisfy tax withholding from the vested units at a weighted average price of $10.544 per share (sales ranged $10.49–$10.64). After the sale the beneficial ownership reported was 15,504 shares. The Form 4 was signed by an attorney-in-fact on 08/22/2025.

Positive

• 8,000 shares issued to the Chief Scientific Officer as performance-based RSUs, indicating achievement of certified performance criteria
• Clear disclosure of vesting schedule: 4,000 shares issued immediately and 4,000 shares subject to service through 08/20/2026
• Sale was tax-related (sell-to-cover) rather than a larger discretionary disposition, reducing potential governance concerns

Negative

• 1,453 shares sold reducing the reporting person's holdings from 16,957 to 15,504 shares
• Weighted average sale price reported only as a range detail; per-price breakdown is not provided on the form (available upon request)

Insights

Securities Analyst

TL;DR: Routine insider vesting and tax-related sale; not a directional signal about company fundamentals.

The filing documents a performance-based vesting event delivering 8,000 shares to the Chief Scientific Officer, with half subject to continued service through 08/20/2026, and a contemporaneous sale of 1,453 shares to cover tax withholding at a weighted average price of $10.544. This pattern—vesting plus sell-to-cover—is common and typically reflects compensation mechanics rather than a deliberate market disposal. The post-transaction beneficial ownership is modest (15,504 shares), limiting potential market impact.

Corporate Governance Expert

TL;DR: Compensation plan functioning as designed; documentation and disclosure appear complete.

The Form 4 explicitly ties the issuance to performance-based restricted stock units granted 02/09/2024 and notes certification by the compensation committee. The split vesting (4,000 shares issued, 4,000 deferred) aligns with typical retention incentives. The sale to cover taxes is disclosed with a weighted average sale price and range; the filer also offers to provide per-price breakdown if requested by SEC staff. Filing was executed via attorney-in-fact with signature dated 08/22/2025, meeting procedural expectations.

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
Estimated average burden
hours per response:			0.5

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^*

Lee Gary K.

(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)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Scientific Officer

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		8,000(1)	A	$0	16,957	D
Common Stock	08/21/2025		S		1,453(2)	D	$10.544(3)	15,504	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, 4,000 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 4,000 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.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What transactions did Gary K. Lee report on the LYEL Form 4?

The Form 4 reports receipt of 8,000 shares on 08/20/2025 from performance-based RSUs and a sale of 1,453 shares on 08/21/2025 to cover tax withholding.

How many of the vested RSU shares remain subject to future service for LYEL?

Of the 8,000 performance-based RSU shares, 4,000 were issued4,000 will be issued

What price did the reporting person receive for the shares sold on LYEL Form 4?

The weighted average sale price was reported as $10.544 per share, with the sale price range noted as $10.49 to $10.64.

What is the reporting person's beneficial ownership after these transactions?

After the issuance and sale the Form 4 reports the reporting person beneficially owned 15,504 shares.

Who signed the Form 4 for Gary K. Lee and when?

The Form 4 was signed by Charles W. Newton, Attorney-in-Fact on 08/22/2025.