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): April 3, 2024

Mallinckrodt plc

(Exact name of registrant as specified in its charter)

College Business & Technology Park, Cruiserath, Blanchardstown, Dublin 15, Ireland

(Address of principal executive offices)

+353 1 6960000

(Registrant’s telephone 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:

Securities registered pursuant to Section 12(b) of the Act: None

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 4.01 Changes in Registrant’s Certifying Accountant.

The Audit Committee (the “Audit Committee”) of the Board of Directors (the “Board”) of Mallinckrodt plc (the “Company”) conducted a competitive process to determine the Company’s independent registered public accounting firm for the fiscal year ending December 27, 2024. As a result of this process, on April 3, 2024, upon the recommendation of the Audit Committee, the Board approved the dismissal of Deloitte & Touche LLP (“Deloitte”) as the Company’s independent registered public accounting firm, effective immediately. Also, on April 3, 2024, the Audit Committee approved the engagement of PricewaterhouseCoopers LLP as the Company’s independent registered public accounting firm for the fiscal year ending December 27, 2024, effective immediately.

The audit reports of Deloitte on the Company’s financial statements as of December 29, 2023 (Successor Company balance sheet) and December 30, 2022 (Predecessor Company balance sheet), and for the period from November 15, 2023 through December 29, 2023 (Successor Company operations), for the period from December 31, 2022 through November 14, 2023 (Predecessor Company operations), for the period from June 17, 2022 through December 30, 2022 (Predecessor Company operations), and for the period from January 1, 2022 through June 16, 2022 (Predecessor Company operations) (the “Audit Periods”), did not contain any adverse opinion or disclaimer of opinion, nor were such reports qualified or modified as to uncertainty, audit scope or accounting principles.

During the Audit Periods and during the period from December 30, 2023 through April 3, 2024, the Company had: (i) no disagreements with Deloitte of the type contemplated by Item 304(a)(1)(iv) of Regulation S-K on any matter of accounting principles or practices, financial statement disclosure or auditing scope or procedure, which, if not resolved to Deloitte’s satisfaction, would have caused it to make reference to the subject matter of any such disagreement in connection with its reports; and (ii) no reportable events within the meaning of Item 304(a)(1)(v) of Regulation S-K.

The Company provided Deloitte with a copy of the disclosures it is making in this Current Report on Form 8-K prior to its filing and requested that Deloitte furnish the Company with a letter addressed to the U.S. Securities and Exchange Commission (the “SEC”) stating whether or not Deloitte agreed with the disclosure in this Item 4.01. A copy of Deloitte’s letter to the SEC in response to the foregoing request is attached as Exhibit 16.1 to this Current Report on Form 8-K.

During the Audit Periods and during the period from December 30, 2023 through April 3, 2024, neither the Company nor anyone on its behalf consulted PricewaterhouseCoopers LLP regarding either (i) the application of accounting principles to a specified transaction, either completed or proposed, or the type of audit opinion that might be rendered on the Company’s consolidated financial statements or (ii) any matter that was the subject of a “disagreement” (within the meaning of Item 304(a)(1)(iv) of Regulation S-K and the related instructions to that Item) or a “reportable event” (within the meaning of Item 304(a)(1)(v) of Regulation S-K).

Item 9.01 Financial Statements and Exhibits.

(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: April 8, 2024