Brian James Harris - 30 Jul 2021 Form 4 Insider Report for Summit Materials, Inc.

Role: EVP & Chief Financial Officer
Signature: /s/ Christopher B. Gaskill, as Attorney-in-Fact
Issuer symbol: N/A
Transactions as of: 30 Jul 2021
Net transactions value: -$109,066
Form type: 4
Filing time: 03 Aug 2021, 17:05:53 UTC
Next filing: 01 Mar 2022
SEC: View on sec.gov

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	SUM	Class A Common Stock	Options Exercise		+13,328	+11%		133,240	30 Jul 2021	Direct	F1
transaction	SUM	Class A Common Stock	Tax liability	$109,066	-3,246	-2.4%	$33.60	129,994	30 Jul 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	-13,328	-50%	$0.000000	13,328	30 Jul 2021	Class A Common Stock	13,328		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 26,656 restricted stock units that vest in two equal annual installments beginning on July 30, 2021.