Company Update

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): March 24, 2026 THERMO FISHER SCIENTIFIC INC. (Exact name of Registrant as specified in its Charter) Delaware 1-8002 04-2209186 (State of incorporation) (Commission File Number) (I.R.S. Employer Identification Number) 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: Title of each class Trading Symbol(s) Name of each exchange on which registered Common Stock, $1.00 par value TMO New York Stock Exchange 1.450% Notes due 2027 TMO 27 New York Stock Exchange 1.750% Notes due 2027 TMO 27B New York Stock Exchange Floating Rate Notes due 2027 TMO 27D New York Stock Exchange 0.500% Notes due 2028 TMO 28A New York Stock Exchange 1.375% Notes due 2028 TMO 28 New York Stock Exchange 1.950% Notes due 2029 TMO 29 New York Stock Exchange 0.875% Notes due 2031 TMO 31 New York Stock Exchange 2.375% Notes due 2032 TMO 32 New York Stock Exchange 3.650% Notes due 2034 TMO 34 New York Stock Exchange 3.628% Notes due 2035 TMO 35A New York Stock Exchange 2.875% Notes due 2037 TMO 37 New York Stock Exchange 1.500% Notes due 2039 TMO 39 New York Stock Exchange 1.875% Notes due 2049 TMO 49 New York Stock Exchange 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.   ☐ Item 8.01    Other Events. On March 24, 2026, Thermo Fisher Scientific Inc. (“Thermo Fisher”) issued a press release announcing the completion of its acquisition of Clario Holdings, Inc. A copy of the press release is attached hereto as Exhibit 99.1 and is incorporated herein by reference. Item 9.01    Financial Statements and Exhibits. (d)    Exhibits 99.1 Press Release of Thermo Fisher Scientific Inc., dated March 24, 2026 104 Cover Page Interactive Data File (embedded within the Inline XBRL document) 2 SIGNATURE 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. THERMO FISHER SCIENTIFIC INC. Date: March 24, 2026 By: /s/ Thomas B. Shropshire Thomas B. Shropshire Senior Vice President and General Counsel 3