Lyell Immunopharma (LYEL) CSO reports small tax-driven sale of company shares

Rhea-AI Filing Summary

Lyell Immunopharma, Inc. Chief Scientific Officer Gary K. Lee reported an automatic share sale tied to tax withholding. On May 11, 2026, 130 shares of common stock were sold at a weighted average price of $18.92 per share to cover tax obligations from the settlement of vested restricted stock units.

After this transaction, Lee directly held 17,808 shares of Lyell Immunopharma common stock. This total includes 1,000 shares acquired on May 18, 2026 under the company’s 2021 Employee Stock Purchase Plan, indicating that the filing reflects both routine compensation-related activity and associated tax withholding.

Insights

Equity compensation and insider trading analyst

Small, routine tax-related sale with limited informational value.

Chief Scientific Officer Gary K. Lee reported the sale of 130 Lyell Immunopharma shares at a weighted average price of $18.92 per share. A footnote explains the sale was automatic to cover tax withholding from vested restricted stock units, a standard equity compensation mechanism.

This characterization places the transaction in the low-signal category, as it does not represent a discretionary decision to reduce exposure. Lee held 17,808 shares after the sale, and the position also reflects 1,000 shares acquired on May 18, 2026 under the 2021 Employee Stock Purchase Plan. The small size and tax-driven nature make this a routine administrative event.

Insider Trade Summary

Net Seller: 130 shares ($2,460)

Net Sell 1 txn

Insider Lee Gary K.

Role Chief Scientific Officer

Sold 130 shs ($2K)

Type	Security	Shares	Price	Value
Sale	Common Stock	130	$18.92	$2K

Holdings After Transaction: Common Stock — 17,808 shares (Direct, null)

Footnotes (1)

1. Shares automatically sold to cover tax withholding obligation from settlement of vested restricted stock units. The price reported above reflects the weighted average price of the shares sold. The sale price ranged from $18.91 to $19.30 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. Includes 1,000 shares acquired on May 18, 2026 under the Issuer's 2021 Employee Stock Purchase Plan.

Key Figures

Shares sold: 130 shares Weighted average sale price: $18.92 per share Post-transaction holdings: 17,808 shares +2 more

5 metrics

Shares sold 130 shares Automatic sale on May 11, 2026 to cover tax withholding

Weighted average sale price $18.92 per share Common stock sale on May 11, 2026

Post-transaction holdings 17,808 shares Common stock directly held after the transaction

ESPP acquisition 1,000 shares Acquired May 18, 2026 under 2021 Employee Stock Purchase Plan

Price range of sales $18.91–$19.30 per share Range of prices for individual trades underlying weighted average

Key Terms

restricted stock units, weighted average price, Employee Stock Purchase Plan

3 terms

restricted stock units financial

"Shares automatically sold to cover tax withholding obligation 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.

weighted average price financial

"The price reported above reflects the weighted average price of the shares sold."

Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.

Employee Stock Purchase Plan financial

"Includes 1,000 shares acquired on May 18, 2026 under the Issuer's 2021 Employee Stock Purchase Plan."

An employee stock purchase plan is a company program that lets workers buy shares through small payroll deductions, often at a discount to the market price and after a set offering period. Think of it like a workplace savings plan that turns into ownership: it encourages employees to share in the company’s success and can create predictable buying or selling of stock that investors watch because it affects supply, demand and employee incentives.

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Form 4 Insider Transactions: What Each Field Means →

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)
05/11/2026

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	05/11/2026		S		130(1)	D	$18.92(2)	17,808(3)	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 $18.91 to $19.30 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 1,000 shares acquired on May 18, 2026 under the Issuer's 2021 Employee Stock Purchase Plan.

	/s/ Mark Meltz, Attorney-in-Fact	06/15/2026
	** 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)

FAQ

What insider transaction did Lyell Immunopharma (LYEL) report for Gary K. Lee?

Lyell Immunopharma reported that Chief Scientific Officer Gary K. Lee sold 130 shares of common stock. The shares were sold at a weighted average price of $18.92 per share in a transaction linked to tax withholding on vested restricted stock units, not a discretionary open-market reduction.

Was the LYEL insider sale by Gary K. Lee a discretionary trade or tax withholding?

The sale was for tax withholding. A footnote explains the 130 shares were automatically sold to cover tax obligations arising from the settlement of vested restricted stock units, indicating a routine compensation-related transaction rather than a voluntary decision to reduce equity exposure in Lyell Immunopharma stock.

How many Lyell Immunopharma (LYEL) shares does Gary K. Lee hold after this Form 4?

After the reported transaction, Gary K. Lee directly holds 17,808 shares of Lyell Immunopharma common stock. This figure reflects his updated ownership position following the 130-share tax-related sale and includes shares acquired through the company’s 2021 Employee Stock Purchase Plan, as noted in the filing footnotes.

At what price were the 130 LYEL shares sold in Gary K. Lee’s Form 4 filing?

The 130 Lyell Immunopharma shares were sold at a weighted average price of $18.92 per share. A footnote clarifies that the actual sale prices ranged from $18.91 to $19.30 per share, and detailed trade breakdowns are available upon request to the issuer, SEC staff, or security holders.

What does the LYEL Form 4 say about price range for Gary K. Lee’s share sale?

The Form 4 states that while the reported price is a weighted average of $18.92, individual trades occurred between $18.91 and $19.30 per share. The reporting person has committed to provide full details of the number of shares sold at each price within this range upon appropriate request.

Did Gary K. Lee acquire additional Lyell Immunopharma (LYEL) shares mentioned in this filing?

Yes. A footnote indicates his holdings include 1,000 shares acquired on May 18, 2026 under Lyell Immunopharma’s 2021 Employee Stock Purchase Plan. This highlights ongoing participation in the company’s employee equity programs alongside the tax-related sale reported in the Form 4 filing.