8-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON,

D.C. 20549

FORM 8-K

CURRENT REPORTPursuant to Section 13 OR 15(d)

of The Securities Exchange Act of 1934

Dateof Report (Date of earliest event reported): September 24, 2024

Smurfit

Westrock plc

(Exact name of registrant as specified in its charter)

BeechHill**, 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:

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. ¨

On July 5, 2024, Smurfit Kappa Group plc (“Smurfit Kappa”), Smurfit Westrock plc, an Irish public limited company formerly known as Smurfit WestRock Limited (“Smurfit Westrock”), WestRock Company (“WestRock”) and Sun Merger Sub, LLC (“Merger Sub”) completed a combination pursuant to a transaction agreement entered into between the parties on September 12, 2023 (the “Transaction Agreement”). Pursuant to the Transaction Agreement and subject to the terms and conditions therein: (a) Smurfit Westrock acquired Smurfit Kappa by means of a scheme of arrangement under the Companies Act 2014 of Ireland (as amended) (the “Scheme”) and (b) Merger Sub merged with and into WestRock (the “Merger,” and together with the Scheme, the “Combination”). Upon completion of the Combination, Smurfit Kappa and WestRock each became wholly owned subsidiaries of Smurfit Westrock.

As previously communicated in the Registration Statement on Form S-4 (as amended by the prospectus) filed in connection with the Combination on April 25, 2024, Smurfit Westrock will manage and report its business in the following three operating segments: Smurfit Westrock Europe, MEA and APAC, Smurfit Westrock North America and Smurfit Westrock Latin America. These segments reflect the legacy Smurfit Kappa segments of Smurfit Kappa Europe and Smurfit Kappa The Americas, with The Americas segment being split into a North American segment composed of the United States, Mexico and Canada, and a Latin American segment being all other countries in the Americas excluding those three countries, combined with legacy WestRock’s business, recast on a corresponding geographic basis. Smurfit Westrock will begin reporting under this segment structure beginning with the third quarter of fiscal 2024.

Smurfit Westrock is furnishing supplemental unaudited historical segment financial information, which conforms to the segment structure described above and represents the total of the individual, unaudited amounts for each of Smurfit Kappa and WestRock for the periods referenced, in the exhibit included as Exhibit 99.1.

The information furnished in this Item 7.01, including the exhibit described above, 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 Exchange Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such a filing.

(d) Exhibits.

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.

Date: September 24, 2024

Exhibit 99.1

Supplemental Unaudited Historical SegmentFinancial Information on a Combined Basis

On July 5, 2024, Smurfit Kappa Group plc (“Smurfit Kappa”), Smurfit Westrock plc, an Irish public limited company formerly known as Smurfit WestRock Limited (“Smurfit Westrock”), WestRock Company (“WestRock”) and Sun Merger Sub, LLC (“Merger Sub”) completed a combination pursuant to a transaction agreement entered into between the parties on September 12, 2023 (the “Transaction Agreement”). Pursuant to the Transaction Agreement and subject to the terms and conditions therein: (a) Smurfit Westrock acquired Smurfit Kappa by means of a scheme of arrangement under the Companies Act 2014 of Ireland (as amended) (the “Scheme”) and (b) Merger Sub merged with and into WestRock (the “Merger,” and together with the Scheme, the “Combination”). Upon completion of the Combination, Smurfit Kappa and WestRock each became wholly owned subsidiaries of Smurfit Westrock.

As previously communicated in the Registration Statement on Form S-4 (as amended by the prospectus) filed in connection with the Combination on April 25, 2024, Smurfit Westrock will manage and report its business in the following three operating segments: Smurfit Westrock Europe, MEA and APAC, Smurfit Westrock North America and Smurfit Westrock Latin America. These segments reflect the legacy Smurfit Kappa segments of Smurfit Kappa Europe and Smurfit Kappa The Americas, with The Americas segment being split into a North American segment composed of the United States, Mexico and Canada, and a Latin American segment being all other countries in the Americas excluding those three countries, combined with legacy WestRock’s business, recast on a corresponding geographic basis. Smurfit Westrock will begin reporting under this segment structure starting with third quarter of fiscal 2024.

The financial information presented below represents the total of the individual, unaudited amounts for each of Smurfit Kappa and WestRock for the periods referenced, as described above and in footnotes below. Such information has not been prepared in compliance with Article 11 of Regulation S-X, nor prepared on a consolidated basis under U.S. GAAP. The non-GAAP combined information provided here may differ materially from the final accounting for the acquisition, any future reported financial results for Smurfit Westrock and any pro forma information we provide in the future in compliance with Article 11 of Regulation S-X.

Adjusted EBITDA is defined as net income before taxes, interest expense, net, depreciation, depletion and amortization expense, goodwill impairment, impairment of other assets, transaction-related expenses associated with the Combination, restructuring costs, legislative or regulatory fines and reimbursements, share-based compensation expense, pension expense (excluding current service cost), and other expense, net. WestRock’s historical adjusted EBITDA has been amended to conform to this definition. Adjusted EBITDA is Smurfit Westrock’s measure of segment profitability in accordance with ASC 280, “Segment Reporting” because it is used by our Chief Operating Decision Maker to make decisions regarding allocation of resources and to assess segment performance.

All values are in US Dollars.