What changed in this filing

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Item 9A. Controls and Procedures

2026-02-24 compared with 2025-02-25 · 26 added, 44 removed, 223 unchanged (24% of the section changed)

30 unchanged sentences

Projections of any evaluation of effectiveness to future periods are subject to the risk that controls

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may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

5 unchanged sentences

Insider Trading Arrangements

During the three months ended December 31, 2024, none of the Company’s directors or executive officers adopted or terminated any Rule 10b5-1 trading arrangements or non-Rule 10b5-1 trading arrangements.

During the three months ended December 31, 2025, none of the Company’s directors or executive officers adopted or terminated a “Rule 10b5-1 trading arrangement” or “non-Rule 10b5-1 trading arrangement,” as each term is defined in Item 408 of Regulation S-K.

Disclosure Regarding Foreign Jurisdictions that Prevent Inspections.

Not Applicable.

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Directors, Executive Officers and Corporate Governance.

6 unchanged sentences

The Company intends to disclose future amendments to certain provisions of the Code of Conduct, and waivers of the Code of Conduct granted to executive officers and directors, if any, on the website within four business days following the date of any amendment or waiver.

Every Merck employee is responsible for adhering to business practices that are in accordance with the law and with ethical principles that reflect the highest standards of corporate and individual behavior.

Every Company employee is responsible for adhering to business practices that are in accordance with the law and with ethical principles that reflect the highest standards of corporate and individual behavior.

The required information on the identification of the audit committee and the audit committee financial expert is incorporated by reference from the discussion under the heading “Board Meetings and Committees” of the Company’s Proxy Statement for the Annual Meeting of Shareholders to be held on May 26, 2026.

1 unchanged sentence

Executive Compensation.

The information required on executive compensation is incorporated by reference from the discussion under the headings “Compensation Discussion and Analysis,” “Summary Compensation Table,” “All Other Compensation” table, “CEO Pay Ratio,” “Pay versus Performance” table, “Grants of Plan-Based Awards” table, “Outstanding Equity Awards” table, “Option Exercises and Stock Vested” table, “Pension Benefits” table, “Nonqualified Deferred Compensation” table, and “Potential Payments Upon Termination or a Change in Control”, as well as all footnote information to the various tables, of the Company’s Proxy Statement for the Annual Meeting of Shareholders to be held on May 27, 2025.

The information required on executive compensation is incorporated by reference from the discussion under the headings “Compensation Discussion and Analysis,” “Summary Compensation Table,” “All Other Compensation”, “CEO Pay Ratio,” “Pay Versus Performance”, “Grants of Plan-Based Awards”, “Outstanding Equity Awards”, “Option Exercises and Stock Vested”, “Pension Benefits”, “Nonqualified Deferred Compensation” table, and “Potential Payments Upon Termination or a Change in Control”, as well as all footnote information to the applicable tables, of the Company’s Proxy Statement for the Annual Meeting of Shareholders to be held on May 26, 2026.

The required information on director compensation is incorporated by reference from the discussion under the heading “Director Compensation” and related “Schedule of Director Fees” table and “2025 Director Compensation” table of the Company’s Proxy Statement for the Annual Meeting of Shareholders to be held on May 26, 2026.

The required information under the headings “Compensation and Management Development Committee Interlocks and Insider Participation” and “Compensation and Management Development Committee Report” is incorporated by reference from the Company’s Proxy Statement for the Annual Meeting of Shareholders to be held on May 26, 2026.

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Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters.

34 unchanged sentences

Ratification of Appointment of Independent Registered Public Accounting Firm for 2026 beginning with the caption “Pre-Approval Policy for Services of Independent Registered Public Accounting Firm” through “Fees for Services Provided by the Independent Registered Public Accounting Firm” of the Company’s Proxy Statement for the Annual Meeting of Shareholders to be held on May 26, 2026.

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Exhibits and Financial Statement Schedules.

11 unchanged sentences

Financial statements of affiliates carried on the equity basis have been omitted because, considered individually or in the aggregate, such affiliates do not constitute a significant subsidiary.

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3.1 — Restated Certificate of Incorporation of Merck & Co., Inc.

(November 3, 2009) — Incorporated by reference to Merck & Co., Inc.’s Current Report on Form 8-K filed November 4, 2009 (No.

(November 3, 2009) — Incorporated by reference to Exhibit 3.1 to Merck & Co., Inc.’s Current Report on Form 8-K filed November 4, 2009 (No.

3.2 — By-Laws of Merck & Co., Inc.

(effective March 22, 2022) — Incorporated by reference to Merck & Co., Inc.’s Current Report on Form 8-K filed March 25, 2022 (No.

(effective N ovember 19, 2024 ) — Incorporated by reference to Exhibit 3.1 to Merck & Co., Inc.’s Current Report on Form 8-K filed N ovember 22 , 2024 (No.

4.1 — Indenture, dated as of April 1, 1991, between Merck Sharp & Dohme Corp.

11 unchanged sentences

Bank Trust National Association, as Trustee — Incorporated by reference to Exhibit 4.1 to Merck & Co., Inc.’s Current Report on Form 8-K filed December 10, 2010 (No.

— I ndenture, dated as of May 30, 2024, among MSD Net herlands Capital B.V., Merck & Co., Inc.

Bank Trust National Association , as Trustee — Incorporated by reference to Exhibit 4.1 to Merck & Co., Inc.

’ s Current Report on Form 8-K filed May 30, 2024 (No.

— D escription of the Registrant ’ s Securities

— Indenture, dated as of May 30, 2024, among MSD Netherlands Capital B.V., Merck & Co., Inc.

Bank Trust National Association, as Trustee — Incorporated by reference to Exhibit 4.1 to Merck & Co., Inc.’s Current Report on Form 8-K filed May 30, 2024 (No.

— Description of the Registrant’s Securities — Incorporated by re ference to Exhibit 4.11 to Merck & Co., Inc.

’ s Form 10-K Annual Report for the fiscal year ended December 31, 2024 filed February 25, 2025 (No.

*10.1 — Merck & Co., Inc.

Executive Incentive Plan (as amended and restated effective January 1, 2025)

Executive Incentive Plan (as amended and restated effective January 1, 2025) — Incor po rated by reference to Exhibit 10.1 to Merck & Co., Inc .

’ s Form 10-K Annual Report for the fiscal year ended December 31, 202 4 filed February 25, 2025 (No .

*10.2 — Merck & Co., Inc.

4 unchanged sentences

2010 Incentive Stock Plan — Incorporated by reference to Exhibit 10.20 to Merck & Co., Inc.’s Form 10-K Annual Report for the fiscal year ended December 31, 2015 filed February 26, 2016 (No.

*10.5 — Form of stock option terms for 2014 quarterly and annual non-qualified option grants under the Merck & Co., Inc.

2010 Incentive Stock Plan — Incorporated by reference to Exhibit 10.18 to Merck & Co., Inc.’s Form 10-K Annual Report for the fiscal year ended December 31, 2014 filed February 27, 2015 (No.

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*10.6 — Form of stock option terms for 2015 quarterly and annual non-qualified option grants under the Merck & Co., Inc.

2010 Incentive Stock Plan — Incorporated by reference to Exhibit 10.20 to Merck & Co., Inc.’s Form 10-K Annual Report for the fiscal year ended December 31, 2015 filed February 26, 2016 (No.

— Form of stock option terms for 2017 annual non-qualified option grants under the Merck & Co., Inc.

12 unchanged sentences

— Merck & Co., Inc.

Separation Benefits Plan (amended and restated as of January 1, 2019) as further amended by Amendments 2019-1 (as of December 19, 2019), 2020-1 (as of February 25, 2020), 2020-2 (as of December 10, 2020), 2021-1 (as of March 31, 2021), 2021-2 (as of December 16, 2021), 2022-1 (as of December 14, 2022), 2022-2 (as of December 13, 2021), 2023-1 (as of December 15, 2023) and 2024-1 (as of October 22, 2024)

’ s Form 10-K Annual Report for the fiscal year ended December 31, 202 4 filed February 25, 2025 (No .

— Retirement Plan for the Directors of Merck & Co., Inc.

6 unchanged sentences

2019 Incentive Stock Plan — Incorporated by reference to Exhibit 10.23 to Merck & Co., Inc.’s Form 10-K Annual Report for the fiscal year ended December 31, 2020 filed February 25, 2021 (No.

— Form of restricted stock unit terms for 2021 annual grants under the Merck & Co., Inc.

2019 Incentive Stock Plan - Incorporated by reference to Exhibit 10.24 to Merck & Co., Inc.’s Form 10-K Annual Report for the fiscal year ended December 31, 2020 filed February 25, 2021 (No.

— Form of stock option terms for 2022 annual non-qualified option grants under the Merck & Co., Inc.

4 unchanged sentences

2019 Incentive Stock Plan — Incorporated by reference to Exhibit 10.25 to Merck & Co., Inc.’s Form 10-K Annual Report for the fiscal year ended December 31, 2022 filed February 24, 2023 (No.

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— Form of restricted stock unit terms for 2020 annual grants under the Merck & Co., Inc.

2019 Incentive Stock Plan — Incorporated by reference to Exhibit 10.27 to Merck & Co., Inc.’s Form 10-K Annual Report for the fiscal year ended December 31, 2022 filed February 24, 2023 (No.

— 2021 Performance Share Unit terms for grants under the Merck & Co., Inc.

2019 Incentive Stock Plan — Incorporated by reference to Exhibit 10.31 to Merck & Co., Inc.’s Form 10-K Annual Report for the fiscal year ended December 31, 2022 filed February 24, 2023 (No.

— Terms for Restricted Stock Unit Grants under the Merck & Co., Inc.

2019 Incentive Stock Plan — Incorporated by reference to Exhibit 10.33 to Merck & Co., Inc.’s Form 10-K Annual Report for the fiscal year ended December 31, 2022 filed February 24, 2023 (No.

— Restricted stock unit terms for August 3, 2022 grant to Chirfi Guindo under the Merck & Co., Inc.

7 unchanged sentences

— 2023 Performance Share Unit terms for grant under the Merck & Co., Inc.

2019 Incentive Stock Plan — Incorporated by reference to Exhibit 10.29 to Merck & Co., Inc.’s Form 10-K Annual Report for the fiscal year ended December 31.

2023 filed February 26, 2024 (No.

— Offer Letter between Merck & Co., Inc.

and Chirfi Guindo, dated June 8, 2022 — Incorporated by reference to Exhibit 10.37 to Merck & Co., Inc.’s Form 10-K Annual Report for the fiscal year ended December 31, 2022 filed February 24, 2023 (No.

2019 Incentive Stock Plan — Incorporated by reference to Exhibit 10.29 to Merck & Co., Inc.’s Form 10-K Annual Report for the fiscal year ended December 31 , 2023 filed February 26, 2024 (No.

— Form of restricted stock unit terms for 2024 annual grants under the Merck & Co., Inc.

2019 Incentive Stock Plan

2019 Incentive Stock Plan — I ncorpo rated by re ference to Exhibit 10.

31 to Merck & Co., Inc.

’ s F orm 10-K Ann ual Report for the fiscal year ended December 31, 202 4 filed February 25, 202 5 (No.

— 2024 Performance Share Unit terms for grants under the Merck & Co., Inc.

2019 Incentive Stock Plan

2019 Incentive Stock Plan — Incorporated by reference to Exhibit 10.3 2 to Merck & Co ., Inc.

’ s F orm 10-K Annual Report for the fiscal year ended D ecember 31, 202 4 filed February 25, 2025 (No.

— Form of stock option terms for 2024 annual non-qualified option grants under the Merck & Co., Inc.

2019 Incentive Stock Plan

— Restricted stock unit terms for April 30, 2024 grant to Richard DeLuca under the Merck & Co., Inc.

2019 Incentive Stock Plan — Incorporated by reference to Exhibit 10.33 to Merck & Co., Inc.’s Form 10-K Annual Report for the fiscal year ended December 31, 2024 filed February 25, 2025 (No.

— Form of restricted stock unit t erms for 2025 annual grants under the Merck & Co., Inc.

2019 Incentive Stock Plan

— Offer Letter between Merck & Co., Inc.

and Betty Larson, dated January 16, 2024

— Restricted stock unit terms for April 30, 2024 grant to Betty Larson under the Merck & Co., Inc.

— 2025 P erformance Share Unit t erms for grants under the Merck & Co., Inc.

2019 Incentive Stock P lan

— Form of stock option terms for 2025 annual non-qualified option grants under the Merck & Co., I nc.

2019 Incentive Stock Plan

19 — Insider Trading Policy

19 — I nsider Trading Policy — Incorporated by reference to Exhibit 19 to Merck & Co., Inc.

’ s Form 10-K Annual Report for the fiscal year ended December 31, 2024 filed February 25, 2025 (No.

21 — Subsidiaries of Merck & Co., Inc.

7 unchanged sentences

— Policy and Procedures for Recoupment of Incentive-Based Compensation — Incorporated by reference to Exhibit 97 to Merck & Co, Inc.’s Form 10-K Annual Report for the fiscal year ended December 31, 2023 filed February 26, 2024 (No.

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101.INS — XBRL Instance Document - The instance document does not appear in the interactive data file because its XBRL tags are embedded within the Inline XBRL document.

11 unchanged sentences

Not applicable.

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Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

34 unchanged sentences

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