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): November 13, 2024

Summit Materials, Inc.

(Exact name of registrant as specified in its charter)

1801 California Street, Suite 3500
Denver, Colorado 80202

(Address of Principal Executive Offices) (Zip Code)

Registrant’s Telephone Number, Including Area Code: (303) 893-0012

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:

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 5.03 Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year.

On November 13, 2024, the Board of Directors (the “Board”) of Summit Materials, Inc. (the “Company”) unanimously approved and adopted the Fourth Amended and Restated Bylaws (as so amended and restated, the “Amended Bylaws”) effective as of such date.

The amendment effected by such Amended Bylaws changes the Company’s fiscal year from a 52-53 week period ending on the Saturday that is closest to December 31st each year, to the period beginning on January 1st and ending on the 31st day of December in each year. The foregoing description is qualified in its entirety by reference to the full text of the Amended Bylaws, a copy of which is filed as Exhibit 3.1 to this Current Report on Form 8-K and is incorporated herein by reference. In addition, a version of the Amended Bylaws that has been marked to show changes from the bylaws that were previously in effect is included as Exhibit 3.2 to this Current Report on Form 8-K and is incorporated herein by reference.

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.