Lyell Immunopharma (NASDAQ: LYEL) CSO sells shares to cover RSU taxes

Rhea-AI Filing Summary

Lyell Immunopharma, Inc. (LYEL) reported an insider transaction by Chief Scientific Officer Gary K. Lee. On 2026-08-21, 1,457 shares of common stock were sold at $15.54 per share. According to the disclosure, these shares were automatically sold to cover a tax withholding obligation from the settlement of vested restricted stock units, leaving 16,220 shares held directly after the transaction.

Insider Trade Summary

Net Seller: 1,457 shares

Net Sell 1 txn

Insider Lee Gary K.

Role Chief Scientific Officer

Sold 1,457 shs ($23K)

Type	Security	Shares	Price	Value
Sale	Common Stock F1	1,457	$15.54	$23K

Holdings After Transaction: Common Stock — 16,220 shares (Direct)

Footnotes (1)

1. F1. Shares automatically sold to cover tax withholding obligation from settlement of vested restricted stock units.

Key Figures

Shares sold: 1,457 shares Sale price per share: $15.54 per share Shares owned after transaction: 16,220 shares

3 metrics

Shares sold 1,457 shares Common stock sale reported for 2026-08-21

Sale price per share $15.54 per share Reported price for the 1,457 common shares sold

Shares owned after transaction 16,220 shares Directly held common stock after the 2026-08-21 sale

Key Terms

restricted stock units, tax withholding obligation, non-derivative

3 terms

restricted stock units financial

"from settlement of vested restricted stock units."

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

tax withholding obligation financial

"sold to cover tax withholding obligation from settlement"

non-derivative financial

"transaction_type": "non-derivative""

FAQ

What insider transaction did LYEL disclose for Gary K. Lee?

Lyell Immunopharma, Inc. disclosed that Chief Scientific Officer Gary K. Lee had 1,457 shares of common stock sold on 2026-08-21, in a transaction associated with tax withholding on vested restricted stock units, at a reported price of $15.54 per share.

How many LYEL shares does Gary K. Lee hold after this Form 4 transaction?

After the reported transaction, Gary K. Lee directly holds 16,220 shares of Lyell Immunopharma, Inc. common stock, as stated in the filing’s post-transaction ownership figure.

Was the LYEL insider sale related to a 10b5-1 trading plan?

No. The filing’s Rule 10b5-1 checkbox is not marked, and there is no footnote indicating that the transaction was made pursuant to a Rule 10b5-1 trading plan.

What was the price and value of the LYEL shares sold by Gary K. Lee?

The filing reports that 1,457 Lyell Immunopharma, Inc. shares were sold at $15.54 per share. This per-share figure is reported as the transaction price in the non-derivative transaction table.

Why were Gary K. Lee’s LYEL shares sold according to the Form 4 footnote?

The footnote states the shares were automatically sold to cover a tax withholding obligation arising from the settlement of vested restricted stock units, rather than being a discretionary open-market sale for investment purposes.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Form 4 Insider Transactions: What Each Field Means →

Available on EDGAR 08/25/2026 - 04:03 PM Accepted by SEC EDGAR 08/25/2026 - 04:03 PM Learn about SEC filing dates

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 CALIFORNIA 94080

(City) (State) (Zip)

UNITED STATES

(Country)

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
08/21/2026

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

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

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

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	08/21/2026		S		1,457(1)	D	$15.54	16,220	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.

	/s/ Mark Meltz, Attorney-in-Fact	08/25/2026
	** 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.
* Form 4: SEC 1474 (03-26)