BENEDICT ANNE LEE (See Remarks) exercised options at SUMMIT MATERIALS, INC.

Option exercise — a mechanical event triggered by vesting or expiry. Not a discretionary conviction trade.

M · 3 exercises

BENEDICT ANNE LEE

Filed: 3/2/2021ACC: 0001104659-21-030926

InsiderBENEDICT ANNE LEECIK 1635215

→

IssuerSUMMIT MATERIALS, INC.CIK 1621563

Officer· See Remarks

Since Feb 2019

-3.74K

Net shares

Net seller

$103.6K

Total sold

Open market trades

0B · 0S

Total transactions

12.54K acquired · 16.28K disposed

Non-Derivative Transactions4

Class A Common Stock

Direct

M · Option Exercise

+2.75K

Price / share

—

Trade value

—

% of position

23.7%

2/28/2021

11.61K→14.37K

Class A Common Stock

Direct

M · Option Exercise

+5.78K

Price / share

—

Trade value

—

% of position

40.2%

2/28/2021

14.37K→20.15K

Class A Common Stock

Direct

M · Option Exercise

+4.01K

Price / share

—

Trade value

—

% of position

19.9%

2/28/2021

20.15K→24.15K

Class A Common Stock

Direct

F · Tax Withholding

−3.74K

Price / share

$27.71

Trade value

$103.64K

% of position

15.5%

2/28/2021

24.15K→20.41K

Total

Net shares

+8.80K

Net value

-$103.64K

Security	Date	Type	Shares	Price / Share	Trade Value	% of Position	Held Before	Held After
Class A Common Stock Direct	2/28/2021	M · Option Exercise	+2.75K	—	—	23.7%	11.61K	14.37K
Class A Common Stock Direct	2/28/2021	M · Option Exercise	+5.78K	—	—	40.2%	14.37K	20.15K
Class A Common Stock Direct	2/28/2021	M · Option Exercise	+4.01K	—	—	19.9%	20.15K	24.15K
Class A Common Stock Direct	2/28/2021	F · Tax Withholding	−3.74K	$27.71	$103.64K	15.5%	24.15K	20.41K
Total			+8.80K		-$103.64K

Derivative Transactions3

Restricted Stock Units

Direct

M · Option Exercise

Converts to

Class A Common Stock

2.75K shares

−2.75K

Strike price

Held after

0.00

Exercisable

—

2/28/2021

Restricted Stock Units

Direct

M · Option Exercise

Converts to

Class A Common Stock

5.78K shares

−5.78K

Strike price

Held after

5.78K

Exercisable

—

2/28/2021

Restricted Stock Units

Direct

M · Option Exercise

Converts to

Class A Common Stock

4.01K shares

−4.01K

Strike price

Held after

8.01K

Exercisable

—

2/28/2021

Security	Converts To	Date	Type	Shares	Exercisable	Held After
Restricted Stock Units Direct	Class A Common Stock2.75K shares	2/28/2021	M · Option Exercise	−2.75K	—	0.00
Restricted Stock Units Direct	Class A Common Stock5.78K shares	2/28/2021	M · Option Exercise	−5.78K	—	5.78K
Restricted Stock Units Direct	Class A Common Stock4.01K shares	2/28/2021	M · Option Exercise	−4.01K	—	8.01K