Anne P. Noonan - Jul 20, 2023 Form 4 Insider Report for Summit Materials, Inc. (SUM)

Role: President & CEO, Director
Signature: /s/ Christopher B. Gaskill, as Attorney-in-Fact
Stock symbol: SUM
Transactions as of: Jul 20, 2023
Transactions value $: -$343,593
Form type: 4
Date filed: 7/21/2023, 04:23 PM
Previous filing: May 5, 2023
Next filing: Mar 4, 2024

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	SUM	Class A Common Stock	Options Exercise		+21.3K	+12.68%		189K	Jul 20, 2023	Direct	F1, F2, F3
transaction	SUM	Class A Common Stock	Tax liability	-$344K	-9.31K	-4.92%	$36.89	180K	Jul 20, 2023	Direct

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	SUM	Restricted Stock Units	Options Exercise	$0	-21.3K	-100%	$0.00^*	0	Jul 20, 2023	Class A Common Stock	21.3K		Direct	F4, F5

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	Reflects restricted stock units that upon vesting converted into shares of Class A common stock of the Issuer ("Class A Common Stock") on a one-for-one basis.
F2	Total holdings include shares of Class A Common Stock received pursuant to a stock dividend paid on December 29, 2022.
F3	Total holdings include shares of Class A Common Stock acquired through the Issuer's Employee Stock Purchase Plan on April 14, 2022.
F4	Each restricted stock unit represents a contingent right to receive one share of Class A common stock of the Issuer ("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 compensation committee.
F5	These restricted stock units vest in three equal annual installments beginning on July 20, 2021.