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

Rhea-AI Filing Summary

Stephen J. Hill, Chief Operating Officer and Director of Lyell Immunopharma (LYEL), reported two small disposition transactions tied to tax withholding for vested restricted stock units. On 08/11/2025 he sold 91 shares at a weighted average price of $10.526 (sale prices ranged $10.045 to $11.00), reducing his beneficial ownership to 8,943 shares. On 08/12/2025 he sold 94 shares at a weighted average price of $10.338 (sale prices ranged $10.120 to $10.415), reducing his beneficial ownership to 8,849 shares.

The Form 4 notes the shares sold were automatically disposed to satisfy tax withholding from vested RSUs, that Hill acquired 390 shares on 05/18/2025 under the company ESPP, and that LYEL effected a 1-for-20 reverse stock split on 05/30/2025; all share figures reflect that split. The Form 4 was signed by an attorney-in-fact on 08/13/2025.

Positive

• Clear disclosure that the shares were sold to satisfy tax withholding obligations from vested RSUs
• Weighted-average sale prices and price ranges are provided for both transactions, improving transparency
• ESP purchase and reverse split are disclosed, explaining reported share counts

Negative

• None.

Insights

Securities Analyst

TL;DR: Routine insider tax-withholding sales; small position changes and clear disclosure — neutral for investors.

The reporting shows two small sales on consecutive days (91 and 94 shares) executed solely to satisfy tax withholding related to vested RSUs, with weighted-average sale prices disclosed and price ranges provided. Post-transaction beneficial ownership is reported as 8,943 and then 8,849 shares. The filing also discloses a 390-share ESPP acquisition on 05/18/2025 and a 1-for-20 reverse split on 05/30/2025; these items explain reported share counts. Given the explicit tax-withholding purpose and modest volumes, this disclosure is routine and unlikely to be material to LYEL equity valuation.

Corporate Governance Expert

TL;DR: Transparent and standard insider reporting; demonstrates compliance with Section 16 disclosure requirements.

The Form 4 provides clear transaction codes, dates, weighted-average prices and sale price ranges, along with explanatory footnotes about tax withholding, ESPP purchases and the reverse split. The signature by an attorney-in-fact on 08/13/2025 indicates timely filing practices. From a governance perspective, this filing reflects appropriate disclosure of insider activity without revealing any new material corporate developments.

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^*

Hill Stephen J.

(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 Operating Officer

3. Date of Earliest Transaction (Month/Day/Year)
08/11/2025

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	08/11/2025		S		91(1)	D	$10.526(2)	8,943(3)(4)	D
Common Stock	08/12/2025		S		94(5)	D	$10.338(6)	8,849(7)	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. Shares automatically sold to cover tax withholding obligation from settlement of vested restricted stock units.

2. The price reported above reflects the weighted average price of the shares sold. The sale price ranged from $10.045 to $11.00 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.

3. Includes 390 shares acquired on May 18, 2025 under the Issuer's 2021 Employee Stock Purchase Plan.

4. On May 30, 2025, the Issuer effected a 1-for-20 reverse stock split of its common stock. All share and amounts reported herein reflect the reverse stock split.

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

6. The price reported above reflects the weighted average price of the shares sold. The sale price ranged from $10.120 to $10.415 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.

7. On May 30, 2025, the Issuer effected a 1-for-20 reverse stock split of its common stock. All share and amounts reported herein reflect the reverse stock split.

	/s/ Allison Peth, Attorney-in-Fact	08/13/2025
	** 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 did LYEL COO Stephen J. Hill report on Form 4?

He reported two dispositions: 91 shares sold on 08/11/2025 and 94 shares sold on 08/12/2025, with weighted-average prices of $10.526 and $10.338, respectively.

Why were the shares sold by Stephen J. Hill (LYEL)?

The Form 4 states the shares were automatically sold to cover tax withholding from the settlement of vested restricted stock units.

How many LYEL shares does Stephen J. Hill beneficially own after these transactions?

The filing reports beneficial ownership of 8,943 shares after the 08/11/2025 transaction and 8,849 shares after the 08/12/2025 transaction.

Were there any other share-related events disclosed in the filing for LYEL?

Yes. The filing notes 390 shares acquired on 05/18/2025 under the Issuer's 2021 ESPP and a 1-for-20 reverse stock split effected on 05/30/2025; all share amounts reflect the split.

What price ranges were reported for the sales on LYEL Form 4?

For 08/11/2025 the sale price range was $10.045 to $11.00; for 08/12/2025 the range was $10.120 to $10.415.

When was the Form 4 signed and filed for Stephen J. Hill (LYEL)?

The document shows a signature by an attorney-in-fact (Allison Peth) dated 08/13/2025.