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): October 29, 2025

Smurfit Westrock plc

(Exact name of registrant as specified in its charter)

Ireland
(State or other jurisdiction of
incorporation)

001-42161

(Commission
File Number)

98-1776979
(I.R.S. Employer
Identification No.)

Beech Hill, Clonskeagh

Dublin 4, D04 N2R2

Ireland

(Address of principal executive offices, including Zip Code)

+353 1 202 7000

(Registrant’s telephone phone number, including area code)

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
Ordinary shares, par value $0.001 per share	SW	New York Stock Exchange (NYSE)

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 2.02.

Results of Operations and Financial Condition

On October 29, 2025, Smurfit Westrock plc (the “Company”) issued a press release announcing the financial results for the third quarter ended September 30, 2025. The press release is furnished as Exhibit 99.1 and is incorporated into this Item 2.02 by reference.

The information provided pursuant to this Item 2.02, including Exhibit 99.1, is being “furnished” and shall not be deemed “filed” hereunder for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or incorporated by reference in any filing under the Securities Act of 1933, as amended (the “Securities Act”), or the Exchange Act, except as shall be expressly set forth by specific reference in any such filings.

Item 7.01.

Regulation FD Disclosure

On October 29, 2025, the Company will host a conference call during which it will discuss the Company’s financial results for the third quarter ended September 30, 2025. The presentation to be used in connection with the conference call is attached as Exhibit 99.2.

The information provided pursuant to this Item 7.01, including Exhibit 99.2, is being “furnished” and shall not be deemed “filed” hereunder for purposes of Section 18 of the Exchange Act or incorporated by reference in any filing under the Securities Act or the Exchange Act, except as shall be expressly set forth by specific reference in any such filings.

Item 9.01.

Financial Statements and Exhibits

(d) Exhibits

99.1

Third Quarter 2025 Earnings Press Release dated October 29, 2025

99.2

Third Quarter 2025 Earnings Presentation

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.

	Smurfit Westrock plc

		/s/ Ken Bowles
	Name:	Ken Bowles
	Title:	Executive Vice President & Group Chief Financial Officer

Date: October 29, 2025

Smurfit Westrock plc 8-K