What changed in this filing

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Item 9A. Controls and Procedures

2026-03-12 compared with 2025-03-11 · 49 added, 67 removed, 121 unchanged (49% of the section changed)

2 unchanged sentences

As of December 31, 2025, management, with the participation and supervision of our Chief Executive Officer and Chief Financial Officer, have evaluated our disclosure controls and procedures as defined in Rules 13a-15(e) and 15d-15(e) of the Exchange Act.

Our disclosure controls and procedures are designed to ensure that information required to be disclosed in the reports we file or submit under the Exchange Act is recorded, processed, summarized and reported within the time periods specified in the SEC’s rules and forms, and that such information is accumulated and communicated to our management, including the Chief Executive Officer and the Chief Financial Officer, to allow timely decisions regarding required disclosures.

Our disclosure controls and procedures are designed to ensure that information required to be disclosed in the reports we file or submit under the Exchange Act is recorded, processed, summarized and reported within the time periods specified in the SEC’s rules and forms, and that such information is accumulated and communicated to our management, including the Chief Executive Officer and Chief Financial Officer, to allow timely decisions regarding required disclosures.

Any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving the desired control objective and management necessarily applies its judgment in evaluating the cost-benefit relationship of possible controls and procedures.

17 unchanged sentences

Based on an evaluation under that framework, our management concluded that our internal control over financial reporting was effective at the reasonable assurance level as of December 31, 2025.

In accordance with SEC staff guidance, which allows companies to exclude certain acquisitions from management’s report on internal control over financial reporting, our assessment of, and conclusion on, the effectiveness of internal control over financial reporting did not include the internal controls of ImmPACT Bio USA Inc., which was acquired during October 2024.

Total assets and operating expenses attributable to the acquisition of ImmPACT Bio USA Inc., represented approximately 3% of our consolidated assets as of December 31, 2024 and 4% of our total operating expenses for the year ended December 31, 2024.

Changes in Internal Control over Financial Reporting

9 unchanged sentences

The full text of our Code of Business Conduct and Ethics may be viewed at the investor relations portion of our website at https://ir.lyell.com, in the section entitled “Governance Highlights” under “Corporate Governance.” We intend to satisfy the disclosure requirements under Item 5.05 of the SEC Form 8-K regarding an amendment to, or waiver from, a provision of our Code of Business Conduct and Ethics by posting such information on our website at the website address and location specified above.

Insider Trading Policy

Our Board of Directors adopted an insider trading policy governing the purchase and sale of, and/or other transactions in, the Company’s securities by our directors, officers, employees and designated consultants that we believe is reasonably designed to promote compliance with insider trading laws, rules and regulations, and the exchange listing standards applicable to us.

Directors, officers, employees and designated consultants may not buy, sell or engage in other transactions in our common stock while aware of material non-public information or engage in hedging or the use of margin accounts involving the Company’s securities;

buy or sell securities of other companies while aware of material non-public information about those companies that they became aware of as a result of business dealings between the Company and those companies;

or disclose material non-public information to any unauthorized persons outside of the Company.

The remainder of the information required by this item is incorporated by reference to our Proxy Statement for the 2026 Annual Meeting of Stockholders to be filed with the SEC within 120 days of the fiscal year ended December 31, 2025 .

19 unchanged sentences

Incorporation by Reference

Number Exhibit Description Form File Number Exhibit/

Reference Filing

Exhibit Description

Agreement and Plan of Merger, dated as of October 24, 2024, by and among the Registrant, ImmPACT Bio USA Inc., Inspire Merger Sub Inc.

and WT Representative LLC, solely in its capacity as the Representative.

2.1 10/24/2024

Amended and Restated Certificate of Incorporation.

S-8 333-257249 4.1 6/21/2021

C ertificate of Amendment of the Ame nded and Restated Certificate of Incorporation of Lyell Immunopharma, Inc.

Amended and Restated Bylaws.

3.2 11/07/2023

Form of Common Stock Certificate.

S-1/A 333-256470 4.1 6/9/2021

Amended and Restated Investors’ Rights Agreement, by and among the Registrant and certain of its stockholders, dated March 5, 2020.

S-1 333-256470 4.2 5/25/2021

Description of Securities

4.3 2/28/2023

Lyell Immunopharma, Inc.

2018 Equity Incentive Plan, as amended.

S-1 333-256470 10.1 5/25/2021

Forms of Stock Option Grant Notice, Stock Option Agreement and Notice of Exercise and Restricted Stock Award Agreement under the Lyell Immunopharma, Inc.

2018 Equity Incentive Plan.

S-1 333-256470 10.2 5/25/2021

Lyell Immunopharma, Inc.

2021 Equity Incentive Plan.

99.3 6/21/2021

Incorporation by Reference

Exhibit Description

Forms of Stock Option Grant Notice, Stock Option Agreement and Notice of Exercise under the Lyell Immunopharma, Inc.

2021 Equity Incentive Plan.

S-1/A 333-256470 10.4 6/9/2021

Incorporation by Reference

Number Exhibit Description Form File Number Exhibit/

Reference Filing

Forms of Restricted Stock Unit Grant Notice and Award Agreement under the Lyell Immunopharma, Inc.

2021 Equity Incentive Plan.

S-1/A 333-256470 10.5 6/9/2021

Lyell Immunopharma, Inc.

2021 Employee Stock Purchase Plan.

99.6 6/21/2021

Lyell Immunopharma, Inc.

Non-Employee Director Compensation Policy.

10.2 11/7/2023

Lyell Immunopharma, Inc.

Officer Severance Plan.

10-K 001-40502 10.8 3/29/2022

Form of Indemnification Agreement by and between the Registrant and its directors and executive officers.

S-1 333-256470 10.9 5/25/2021

Amended Offer Letter by and between the Registrant and Richard Klausner, dated July 23, 2020.

S-1 333-256470 10.10 5/25/2021

Offer Letter, by and between the Registrant and Lynn Seely, dated December 14, 2022

8-K 001-40502 10.2 12/16/2022

Offer Letter by and between the Registrant and Charles Newton, dated February 3, 2021.

S-1 333-256470 10.12 5/25/2021

Offer Letter by and between the Registrant and Stephen Hill, dated May 9, 2019.

S-1 333-256470 10.14 5/25/2021

Offer Letter by and between the Registrant and Matthew Lang, dated May 12, 2023.

10.1 11/07/2023

Offer Letter by and between the Registrant and Gary Lee, dated November 24, 2021.

10.16 2/28/2024

O ffer Letter by and between the Re gistrant and Mark Meltz, dated June 4, 2025.

O ffer Letter by and between the Registrant and David Shook, dated June 3, 2025.

Severance Waiver by and between the Registrant and Stephen Hill, dated April 19, 2022.

10-Q 001-40502 10.1 5/10/2022

O ff er Letter , by and between the Registrant and Smital Shah, dated March 3, 2026.

Standard Office Lease for Building C by and between the Registrant and Bre Wa Office Owner LLC, dated August 28, 2019.

S-1 333-256470 10.19 5/25/2021

Standard Office Lease for Building E by and between the Registrant and Bre Wa Office Owner LLC, dated August 28, 2019.

S-1 333-256470 10.20 5/25/2021

Lease by and between the Registrant and BMR-500 Fairview Avenue LLC, dated November 27, 2018, as amended.

S-1 333-256470 10.21 5/25/2021

Lease Agreement by and between the Registrant and ARE-San Francisco No.

65, LLC, dated August 15, 2019, as amended.

S-1 333-256470 10.22 5/25/2021

10.21 Registration Rights Agreement, dated as of October 31, 2024, by and among Lyell Immunopharma, Inc., each of the Sellers Party thereto and WT Representative LLC, solely in its capacity as the Representative of the Sellers.

10.1 10/31/2024

Incorporation by Reference

Number Exhibit Description Form File Number Exhibit/

Reference Filing

Exhibit Description

Registration Rights Agreement, dated as of October 31, 2024, by and among the Registrant , each of the Sellers Party thereto and WT Representative LLC, solely in its capacity as the Representative of the Sellers.

Exclusive License Agreement by and between Kalthera, Inc., a subsidiary of the Registrant, and the Regents of the University of California, acting through The Technology Development Group of the University of California, Los Angeles (UCLA), dated February 18, 2021, as amended.

19.1 L yell Immunopharma, Inc.

S ecurities Purchase A greement by and among the Registrant and the Purchasers listed therein, dated July 24, 2025.

Exclusive License Agreement by and between the Registrant and Innovative Cellular Therapeutics Holdings Limited and Innovative Cellular Therapeutics, Inc., dated November 6, 2025.

R egistration Rights Agreement by and between the Registra nt and Innovative Cell ular Therapeutics Holdings Limited, dated November 6, 2025.

Lyell Immunopharma, Inc.

Insider Trading Policy.

6 unchanged sentences

Incentive Compensation Recoupment Policy dated September 6, 2023.

97.1 2/28/2024 X

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Incorporation by Reference

Exhibit Description

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Cover Page Interactive Data File.

10 unchanged sentences

POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below constitutes and appoints Lynn Seely, Charles Newton and Matthew Lang, and each of them, as his or her true and lawful attorneys-in-fact and agents, with full power of substitution and resubstitution, for him or her and in his or her name, place and stead, in any and all capacities, to sign any and all amendments to this Annual Report on Form 10-K, and to file the same, with all exhibits thereto and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite and necessary to be done in connection therewith, as fully to all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents, or any of them, or their or his or her substitute or substitutes, may lawfully do or cause to be done by virtue hereof.

KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below constitutes and appoints Lynn Seely, Smital Shah and Mark Meltz, and each of them, as his or her true and lawful attorneys-in-fact and agents, with full power of substitution and resubstitution, for him or her and in his or her name, place and stead, in any and all capacities, to sign any and all amendments to this Annual Report on Form 10-K, and to file the same, with all exhibits thereto and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite and necessary to be done in connection therewith, as fully to all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents, or any of them, or their or his or her substitute or substitutes, may lawfully do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Act of 1934, this Annual Report on Form 10-K has been signed by the following persons on behalf of the Registrant and in the capacities and on the dates indicated:

Signature Title Date

/s/ LYNN SEELY President, Chief Executive Officer and Director March 11, 2025

/s/ LYNN SEELY

President, Chief Executive Officer and Director

March 12, 2026

Lynn Seely, M.D.

(Principal Executive Officer)

/s/ CHARLES NEWTON Chief Financial Officer March 11, 2025

Charles Newton (Principal Financial and Accounting Officer)

/s/ SMITAL SHAH

Chief Financial and Business Officer

March 12, 2026

(Principal Financial Officer)

/s/ VERONICA SANCHEZ

VP, Controller

March 12, 2026

Veronica Sanchez

(Principal Accounting Officer)

/s/ RICHARD D.

KLAUSNER Chair of the Board of Directors March 11, 2025

Chair of the Board of Directors

March 12, 2026

Klausner, M.D.

/s/ OTIS BRAWLEY Director March 11, 2025

/s/ MARK BACHLEDA

March 12, 2026

Mark Bachleda, Pharm.D.

/s/ OTIS BRAWLEY

March 12, 2026

Otis Brawley, M.D.

/s/ CATHERINE FRIEDMAN Director March 11, 2025

/s/ CATHERINE FRIEDMAN

March 12, 2026

Catherine Friedman

/s/ ELIZABETH NABEL Director March 11, 2025

/s/ ELIZABETH NABEL

March 12, 2026

Elizabeth Nabel, M.D.

/s/ ROBERT NELSEN Director March 11, 2025

Robert Nelsen

/s/ SUMANT RAMACHANDRA

Director March 11, 2025

March 12, 2026

Sumant Ramachandra, M.D., Ph.D.

/s/ WILLIAM RIEFLIN Director March 11, 2025

/s/ WILLIAM RIEFLIN

March 12, 2026

William Rieflin

Compared sentence by sentence after normalising whitespace, quotation marks, case and digits, so re-formatting and restated figures do not read as changed language. Wording changes appear as one removal and one addition. The current filing and the prior one are authoritative.

What changed 10-K

Item 9A. Controls and Procedures