TREX CO INC — Director's Dealing 2021

May 12, 2021

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: TREX CO INC (TREX)
CIK: 0001069878
Period of Report: 2021-05-11

Reporting Person: Gupp William R. (Sr VP,Gen. Counsel & Secretary)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2021-05-11	Common Stock	M	14000	$5.485	Acquired	117455	Direct
2021-05-11	Common Stock	D	724	$106.10	Disposed	116731	Direct
2021-05-11	Common Stock	F	5988	$106.10	Disposed	110743	Direct
2021-05-12	Common Stock	S	7288	$102.85	Disposed	103455	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2021-05-11	Stock Appreciation Right	$5.485	M	14000	Disposed	2023-02-12	Common Stock (14000)	Direct

Footnotes

F1: Stock Appreciation Rights (SARs) are being exercised pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on August 5, 2020.

F2: 5,988 shares are being surrendered as allowed by the Company's 2014 Stock Incentive Plan to cover the payment of taxes currently due on previously granted restricted shares.

F3: The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 sales plan adopted by the reporting person on August 5, 2020.