TREX CO INC — Director's Dealing 2018

May 11, 2018

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: TREX CO INC (TREX)
CIK: 0001069878
Period of Report: 2018-05-09

Reporting Person: Cline James E (Director, President and CEO)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2018-05-09	Common Stock	M	9286	$12.78	Acquired	55236	Direct
2018-05-09	Common Stock	D	1051	$112.96	Disposed	54185	Direct
2018-05-09	Common Stock	F	3714	$112.96	Disposed	50471	Direct
2018-05-09	Common Stock	S	2400	$112.6959	Disposed	48071	Direct
2018-05-09	Common Stock	S	5290	$113.5831	Disposed	42781	Direct
2018-05-09	Common Stock	S	5810	$114.4098	Disposed	36971	Direct
2018-05-10	Common Stock	S	4051	$113.2158	Disposed	32920	Direct
2018-05-10	Common Stock	S	470	$114.1031	Disposed	32450	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2018-05-09	Stock Appreciation Right	$12.78	M	9286	Disposed	2022-02-15	Common Stock (9286)	Direct

Footnotes

F1: Stock Appreciation Rights are being exercised pursuant to a Rule 10b5-1 sales plan adopted by the reporting person on August 24, 2017.

F2: 3,714 shares are being surrendered as allowed by the Company's 2014 Stock Incentive Plan to cover the payment of taxes currently due on the exercise of SARs.

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 24, 2017.

F4: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $112.39 to $112.99, inclusive. The reporting person undertakes to provide Trex Company, Inc., any security holder of Trex Company, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in Footnote (4) to this Form 4.

F5: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $113.00, to $113.99, inclusive.

F6: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $114.01 to $115.00, inclusive.

F7: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $112.895 to $113.745, inclusive.

F8: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $114.05 to $114.285, inclusive.