Anne P. Noonan - Jul 20, 2021 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, 2021
Transactions value $: -$197,757
Form type: 4
Date filed: 7/22/2021, 04:26 PM
Next filing: Mar 1, 2022

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	+32.26%		87.3K	Jul 20, 2021	Direct	F1
transaction	SUM	Class A Common Stock	Tax liability	-$198K	-6.15K	-7.05%	$32.14	81.1K	Jul 20, 2021	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	-33.33%	$0.00	42.6K	Jul 20, 2021	Class A Common Stock	21.3K		Direct	F2, F3

* 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	Each restricted stock unit represents a contingent right to receive one share of 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.
F3	The Reporting Person was granted 68,866 restricted stock units that vest in three equal annual installments beginning on July 20, 2021.