ATCO Atlas Corporation

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

Form 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16

OF THE SECURITIES EXCHANGE ACT OF 1934

Date of Report: February 1, 2023

Commission File Number 001-39237

ATLAS CORP.

(Exact name of Registrant as specified in its Charter)

23 Berkeley Square

London, United Kingdom

W1J 6HE

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F. Form 20-F  ☒     Form 40-F  ☐

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101 (b)(1).     Yes  ☐    No  ☒

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101 (b)(7).     Yes  ☐    No  ☒

This report on Form 6-K of Atlas Corp., or this Report, is hereby incorporated by reference into: the Registration Statement of Atlas Corp. filed with the Securities and Exchange Commission, (the “SEC”), on May 30, 2008 on Form F-3D (Registration No. 333-151329), as amended on February 28, 2020, the Registration Statement of Atlas Corp. filed with the SEC on March 31, 2011 on Form S-8 (Registration No. 333-173207), as amended on February 28, 2020, the Registration Statement of Atlas Corp. filed with the SEC on June 20, 2013 on Form S-8 (Registration No. 333-189493), as amended on February 28, 2020, the Registration Statement of Atlas Corp. filed with the SEC on April 24, 2012 on Form F-3 (Registration No. 333-180895), as amended on March 22, 2013 and February 28, 2020, the Registration Statement of Atlas Corp. filed with the SEC on April 29, 2014 on Form F-3 (Registration No. 333-195571), as amended on March 6, 2017, April 19, 2017 and February 28, 2020, the Registration Statement of Atlas Corp. filed with the SEC on November 28, 2014 on Form F-3 (Registration No. 333-200639), as amended on March 6, 2017, April 19, 2017 and February 28, 2020, the Registration Statement of Atlas Corp. filed with the SEC on November 28, 2014 on Form S-8 (Registration No. 333-200640), as amended on February 28, 2020, the Registration Statement of Atlas Corp. filed with the SEC on March 12, 2015 on Form F-3D (Registration No. 333-202698), as amended on February 28, 2020, the Registration Statement of Atlas Corp. filed with the SEC on June 24, 2016 on Form S-8 (Registration No. 333-212230), as amended on February 28, 2020, the Registration Statement of Atlas Corp. filed with the SEC on August 25, 2017 on Form F-3 (Registration No. 333-220176), as amended on February 28, 2020, the Registration Statement of Atlas Corp. filed with the SEC on December 21, 2017 on Form S-8 (Registration No. 333-222216), as amended on February 28, 2020, the Registration Statement of Atlas Corp. filed with the SEC on April 13, 2018 on Form F-3D (Registration No. 333-224291), as amended on February 28, 2020, the Registration Statement of Atlas Corp. filed with the SEC on April 13, 2018 on Form F-3 (Registration No. 333-224288), as amended on May 3, 2018, May 7, 2018 and February 28, 2020, the Registration Statement of Atlas Corp. filed with the SEC on September 28, 2018 on Form F-3 (Registration No. 333-227597), as amended on February 28, 2020, the Registration Statement of Atlas Corp. filed with the SEC on January 18, 2019 on Form F-3 (Registration No. 333-229312), as amended on February 28, 2020, the Registration Statement of Atlas Corp. filed with the SEC on March 27, 2019 on Form F-3 (Registration No. 333-230524), as amended on February 28, 2020, the Registration Statement of Atlas Corp. filed with the SEC on May 11, 2020 on Form F-3 (Registration No. 333-238178), as supplemented on December 7, 2020, the Registration Statement of Atlas Corp. filed with the SEC on June 30, 2020 on Form S-8 (Registration No. 333-239578), the Registration Statement of Atlas Corp. filed with SEC on March 19, 2021 on Form F-3 (Registration No. 333-254536), the Registration Statement of Atlas Corp. filed with the SEC on July 16, 2021 on Form F-3 (Registration No. 333-257967), and the Registration Statement of Atlas Corp. filed with the SEC on March 25, 2022 on Form S-8 (Registration No. 333-263872).

Information Contained in this Form 6-K Report

Atlas Corp. (the “Company”) is providing an update on the regulatory approval process in connection with the Agreement and Plan of Merger, dated October 31, 2022 (the “Merger Agreement”), with Poseidon Acquisition Corp. (“Poseidon”). The Company has now received regulatory confirmation for the transaction to proceed from Brazil’s Administrative Council for Economic Defence, Turkey’s Competition Authority and Australia’s Competition and Consumer Commission and as announced on December 21, 2022, the Federal Trade Commission and Department of Justice permitted the 30-day customary waiting period to expire. The Company continues to expect to complete the transactions contemplated by the Merger Agreement in the first half of 2023.

As previously disclosed on a Report on Form 6-K furnished with the Securities and Exchange Commission on November 1, 2022, the Company entered into the Merger Agreement with Poseidon and a wholly-owned subsidiary of Poseidon (“Merger Sub”), pursuant to which, among other things, and subject to the satisfaction or waiver of the conditions set forth therein, Merger Sub will merge with and into the Company, with the Company continuing as the surviving corporation and a wholly-owned subsidiary of Poseidon (other than with respect to the Company’s preferred shares).

Cautionary Note Regarding Forward-Looking Statements

This report contains “forward-looking statements.” All statements, other than statements of historical facts, that address activities, events or developments that the Company expects, projects, believes or anticipates will or may occur in the future are forward-looking statements. You are cautioned not to rely on these forward-looking statements, which speak only as the date of this report. The Company undertakes no obligation and does not intend to update these forward-looking statements to reflect events or circumstances occurring after this report. These statements are based on current expectations of future events, are not guarantees of future performance and are

subject to risks, uncertainties and other factors, some of which are beyond the Company’s control and are difficult to predict. These risks and uncertainties include the risks that the transactions contemplated by the Merger Agreement may not be consummated due to the failure to satisfy conditions to completion of the merger, the occurrence of any event, change or other circumstance that gives rise to the termination of the Merger Agreement or otherwise. If underlying assumptions prove inaccurate or unknown risks or uncertainties materialize, actual events could vary materially from the Company’s expectations. When considering these forward-looking statements, you should keep in mind the risk factors and other cautionary statements found in the Company’s filings with the SEC, which include, but are not limited to, those found in the Company’s Annual Report on Form 20-F for the year ended December 31, 2021, filed with the SEC on March 24, 2022, the Company’s Proxy Statement filed as an exhibit to Schedule 13e-3, filed with the SEC on January 9, 2023, and the Company’s other filings with the SEC.