• $1,000,000,000 aggregate principal amount of its 18-month floating rate senior notes due 2023 (the "18-Month Floating Rate Notes"),
• $500,000,000 aggregate principal amount of its floating rate senior notes due 2023 (the "2023 Floating Rate Notes"),
• $500,000,000 aggregate principal amount of its floating rate senior notes due 2024 (collectively with the 18-Month Floating Rate Notes and the 2023 Floating Rate Notes, the "Floating Rate Notes"),
• $1,350,000,000 aggregate principal amount of its 0.797% senior notes due 2023 (the "2023 Notes"), and
• $2,500,000,000 aggregate principal amount of its 1.215% senior notes due 2024 (together with the 2023 Notes, the "Fixed Rate Notes" and, collectively with the Floating Rate Notes, the "Notes").

The Offering is expected to close on or about October 22, 2021, subject to customary closing conditions. The Floating Rate Notes will pay interest quarterly. The Fixed Rate Notes will pay interest on a semi-annual basis.

Thermo Fisher intends to use the net proceeds of the Offering to pay a portion of the cash consideration payable for the proposed acquisition of PPD, Inc., a Delaware corporation. Thermo Fisher may also determine to use a portion of the net proceeds of the Offering for general corporate purposes, which may include the acquisition of companies or businesses, repayment and refinancing of debt, working capital and capital expenditures or the repurchase of its outstanding equity securities or it may temporarily invest the net proceeds in short-term, liquid investments until they are used for their ultimate purpose.

The joint book-running managers for the Offering are Barclays Capital Inc., Morgan Stanley & Co. LLC, BofA Securities, Inc., Citigroup Global Markets Inc. and Mizuho Securities USA LLC.

The Offering is being made pursuant to an effective registration statement on Form S-3 filed with the U.S. Securities and Exchange Commission (the "SEC"). Prospective investors should read the prospectus forming a part of that registration statement and the prospectus supplement related to the Offering and the other documents that Thermo Fisher has filed with the SEC for more complete information about Thermo Fisher and this Offering. These documents are available at no charge by visiting EDGAR on the SEC website at www.sec.gov. Alternatively, Thermo Fisher, the underwriters or any dealer participating in the Offering will arrange to send you the prospectus if you request it by calling Barclays Capital Inc. toll-free at 1-888-603-5847; Morgan Stanley & Co. LLC toll-free at 1-866-718-1649; BofA Securities, Inc. toll-free at 1-800-294-1322; Citigroup Global Markets Inc. toll-free at 1-800-831-9146; or Mizuho Securities USA LLC toll-free at 1-866-271-7403.