Merck (NYSE: MRK) issues new notes due 2027–2055 in public deal

Rhea-AI Filing Summary

Merck & Co., Inc. completed an underwritten public offering of new investment-grade debt across multiple maturities. The company issued $500,000,000 of Floating Rate Notes due 2027, $750,000,000 of 3.850% Notes due 2027, $750,000,000 of 4.150% Notes due 2030, $1,000,000,000 of 4.550% Notes due 2032, $1,750,000,000 of 4.950% Notes due 2035, and $1,250,000,000 of 5.700% Notes due 2055 under an existing shelf registration. All notes were issued under Merck’s longstanding indenture with U.S. Bank Trust National Association, and the filing also attaches officers’ certificates and a legal opinion related to the new series.

Insights

Corporate finance analyst

Merck adds several new bond series across 2027–2055 maturities.

Merck & Co., Inc. has expanded its long-term funding profile by issuing several tranches of notes, ranging from a short‑dated floating rate note due 2027 to a long‑dated 5.700% series due 2055. The debt was sold in an underwritten public offering off an automatic shelf, indicating access to public markets under standard terms.

The mix of floating and fixed coupons and staggered maturities from 2027 through 2035 and 2055 helps distribute future refinancing points over time. Actual balance sheet impact, including leverage and interest expense, will depend on how the proceeds relate to existing cash, debt and future uses, which are not detailed in this excerpt.

The attached officers’ certificates and the general counsel’s legal opinion formalize the terms and validity of each series under the existing indenture dated January 6, 2010. Subsequent periodic filings may provide more context on how this additional debt fits into Merck’s broader capital allocation and funding strategy.

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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) September 9, 2025

Merck & Co., Inc.

(Exact name of registrant as specified in its charter)

New Jersey			1-6571			22-1918501
(State or other jurisdiction			(Commission			(I.R.S Employer
of incorporation)			File Number)			Identification No.)

126 East Lincoln Avenue, Rahway, New Jersey			07065
(Address of principal executive offices)			(Zip Code)

(Registrant’s telephone number, including area code) (908) 740-4000

Not Applicable

(Former name or former address, if changed since last report.)

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:

☐ 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 ($0.50 par value)

MRK

New York Stock Exchange

1.875% Notes due 2026

MRK/26

New York Stock Exchange

3.250% Notes due 2032

MRK/32

New York Stock Exchange

2.500% Notes due 2034

MRK/34

New York Stock Exchange

1.375% Notes due 2036

MRK 36A

New York Stock Exchange

3.500% Notes due 2037

MRK/37

New York Stock Exchange

3.700% Notes due 2044

MRK/44

New York Stock Exchange

3.750% Notes due 2054

MRK/54

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 September 9, 2025, Merck & Co., Inc. (the “Company”) closed an underwritten public offering of $500,000,000 aggregate principal amount of Floating Rate Notes due 2027 (the “Floating Rate Notes”), $750,000,000 aggregate principal amount of 3.850% Notes due 2027 (the “2027 Notes”), $750,000,000 aggregate principal amount of 4.150% Notes due 2030 (the “2030 Notes”), $1,000,000,000 aggregate principal amount of 4.550% Notes due 2032 (the “2032 Notes”), $1,750,000,000 aggregate principal amount of 4.950% Notes due 2035 (the “2035 Notes”) and $1,250,000,000 aggregate principal amount of 5.700% Notes due 2055 (the “2055 Notes” and, together with the Floating Rate Notes, the 2027 Notes, the 2030 Notes, the 2032 Notes and the 2035 Notes, collectively, the “Notes”) under the Company’s Registration Statement on Form S-3ASR (Registration No. 333-278066), originally filed with the Securities and Exchange Commission (the “Commission”) on March 19, 2024, as amended by Post-Effective Amendment No. 1, filed with the Commission on May 14, 2024.

The Notes are being issued under an indenture dated as of January 6, 2010, between the Company and U.S. Bank Trust National Association, as trustee, a copy of which was attached as Exhibit 4.1 to the Company’s Current Report on Form 8-K previously filed with the Securities and Exchange Commission on December 10, 2010 and is incorporated herein by reference. Copies of the officers’ certificate for each series of the Notes (including forms of each of the respective Notes attached thereto) pursuant to Section 301 of the indenture governing the Notes are attached hereto as Exhibits 4.1, 4.2, 4.3, 4.4, 4.5 and 4.6 and are incorporated herein by reference. The legal opinion related to these Notes is attached hereto as Exhibit 5.1 and is incorporated herein by reference.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits 

Exhibit 4.1						Floating Rate Notes due 2027 Officers’ Certificate of the Company dated September 9, 2025, including form of the Floating Rate Notes.
Exhibit 4.2						3.850% Notes due 2027 Officers’ Certificate of the Company dated September 9, 2025, including form of the 2027 Notes.
Exhibit 4.3						4.150% Notes due 2030 Officers’ Certificate of the Company dated September 9, 2025, including form of the 2030 Notes.
Exhibit 4.4						4.550% Notes due 2032 Officers’ Certificate of the Company dated September 9, 2025, including form of the 2032 Notes.
Exhibit 4.5						4.950% Notes due 2035 Officers’ Certificate of the Company dated September 9, 2025, including form of the 2035 Notes.
Exhibit 4.6						5.700% Notes due 2055 Officers’ Certificate of the Company dated September 9, 2025, including form of the 2055 Notes.
Exhibit 5.1						Opinion and Consent of Jennifer Zachary, Esq., Executive Vice President and General Counsel of the Company.
Exhibit 23.1						Consent of Jennifer Zachary, Esq., Executive Vice President and General Counsel of the Company (contained in Exhibit 5.1 to this Current Report on Form 8-K).
Exhibit 104						Cover Page Interactive Data File (embedded within the Inline XBRL document).

SIGNATURES

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.

			Merck & Co., Inc.
Date: September 9, 2025			By:						/s/ Kelly E. W. Grez
									Kelly E. W. Grez
									Corporate Secretary

FAQ

What did Merck (MRK) announce in this Form 8-K?

Merck & Co., Inc. reported that it closed an underwritten public offering of several series of notes, including Floating Rate Notes due 2027 and fixed-rate notes maturing between 2027 and 2055, issued under its existing shelf registration.

How much of each new Merck (MRK) note series was issued?

Merck issued $500,000,000 of Floating Rate Notes due 2027, $750,000,000 of 3.850% Notes due 2027, $750,000,000 of 4.150% Notes due 2030, $1,000,000,000 of 4.550% Notes due 2032, $1,750,000,000 of 4.950% Notes due 2035, and $1,250,000,000 of 5.700% Notes due 2055.

Under what registration statement were Merck's new notes offered?

The notes were offered under Merck’s Registration Statement on Form S-3ASR (Registration No. 333-278066), originally filed on March 19, 2024 and amended by Post-Effective Amendment No. 1 filed on May 14, 2024.

Which indenture governs the new Merck (MRK) notes?

The new notes are governed by an indenture dated January 6, 2010, between Merck & Co., Inc. and U.S. Bank Trust National Association, as trustee, which is incorporated by reference.

What exhibits were filed with Merck’s 8-K for the new notes?

Exhibits include officers’ certificates for each series of notes (Exhibits 4.1–4.6), a legal opinion and consent from Executive Vice President and General Counsel Jennifer Zachary (Exhibits 5.1 and 23.1), and the cover page interactive data file (Exhibit 104).

Do the new Merck notes trade on an exchange?

The filing lists several existing Merck securities registered under Section 12(b), including various notes and the common stock on the New York Stock Exchange, and describes the newly issued notes as part of a public offering under that framework.