Summit Materials (SUM) Form 3 Summit Materials / David Loomes ownership change

SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person^*

Loomes David

(Last) (First) (Middle)

1801 CALIFORNIA STREET

SUITE 3500

(Street)

DENVER CO 80202

(City) (State) (Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
01/12/2024

3. Issuer Name and Ticker or Trading Symbol
Summit Materials, Inc. [ SUM ]

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director	10% Owner
X	Officer (give title below)	Other (specify below)
See Remarks

5. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Class A Common Stock	11,895(1)(2)	D

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Restricted Stock Units(3)	(3)	(3)	Class A Common Stock	2,703	(4)	D
Restricted Stock Units(5)	(5)	(5)	Class A Common Stock	4,500	(4)	D
Restricted Stock Units(6)	(6)	(6)	Class A Common Stock	7,766	(4)	D

Explanation of Responses:

1. Total holdings include shares of Class A Common Stock received pursuant to a stock dividend paid on December 29, 2022.

2. Total holdings include shares of Class A Common Stock acquired through the Issuer's Employee Stock Purchase Plan on October 18, 2022, May 28, 2023 and November 30, 2023.

3. These restricted stock units vest on February 28, 2024.

4. Each restricted stock unit represents a contingent right to receive one share of Class A Common Stock. The restricted stock units will be settled in either Class A Common Stock or cash (or a combination thereof) at the discretion of the Issuer's Human Capital and Compensation Committee.

5. The Reporting Person was granted 6,750 restricted stock units that vest in three equal annual installments beginning on February 28, 2023.

6. The Reporting Person was granted 7,766 restricted stock units that vest in three equal annual installments beginning on February 28, 2024.

Remarks:

Title: EVP, Cement Exhibit 24 - Power of Attorney

	/s/ David Hamm, as Attorney-in-Fact	01/19/2024
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 5 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
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