Washington, D.C. 20549

FORM 8-K

Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): January 12, 2026

THERMO FISHER SCIENTIFIC INC.

(Exact name of Registrant as specified in its Charter)

168 Third Avenue

Waltham, Massachusetts 02451

(Address of principal executive offices) (Zip Code)

Registrant’s telephone number, including area code: (781) 622-1000

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

☐	Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐	Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐	Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐	Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.  ☐

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Each of Michel Lagarde and Frederick M. Lowery have notified Thermo Fisher Scientific Inc. (the “Company”) of their decisions to leave the Company to pursue other opportunities. Mr. Lagarde, who has served as Executive Vice President and Chief Operating Officer of the Company since 2021 will depart on March 31, 2026, and Mr. Lowery, who has served as an Executive Vice President of the Company since 2024 will depart on February 28, 2026.

Effective March 1, 2026, Thermo Fisher Scientific will update its organizational structure and leadership team. Marc N. Casper will become Chairman and Chief Executive Officer. Gianluca Pettiti, currently an Executive Vice President, will be promoted and transition to the role of President and Chief Operating Officer. Also, as of that date, Michael Shafer, currently an Executive Vice President, will be promoted to an expanded role and will report directly to the Chief Executive Officer.

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.