TREX CO INC — Director's Dealing 2012

May 11, 2012

SEC Form 4/A — Form 4/A

Issuer: TREX CO INC (TREX)
CIK: 0001069878
Period of Report: 2012-05-01

Reporting Person: KAPLAN RONALD W (Director, President and CEO)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2012-05-01	Common Stock	M	23355	$8.80	Acquired	131211	Direct
2012-05-01	Common Stock	M	10645	$9.14	Acquired	141856	Direct
2012-05-01	Common Stock	D	9529	$31.78	Disposed	132327	Direct
2012-05-01	Common Stock	F	10327	$31.78	Disposed	122000	Direct
2012-05-01	Common Stock	S	8000	$32.0356	Disposed	114000	Direct
2012-05-03	Common Stock	S	14144	$32.3979	Disposed	99856	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2012-05-01	Stock Appreciation Right	$8.80	M	23355	Disposed	2018-01-07	Common Stock (23355)	Direct
2012-05-01	Stock Appreciation Right	$9.14	M	10645	Disposed	2018-05-07	Common Stock (10645)	Direct

Footnotes

F1: 23,355 Stock Appreciation Rights (SARs) are being exercised pursuant to Rule 10b5-1 trading plan adopted by the reporting person on November 1, 2011.

F2: 10,645 Stock Appreciation Rights (SARs) are being exercised pursuant to Rule 10b5-1 trading plan adopted by the reporting person on November 1, 2011.

F3: The stock appreciation right becomes exerciseable in three equal installments beginning on the first anniversary date of the transaction date.

F4: 10,327 shares are being surrendered as allowed by the Company's 2005 Stock Incentive Plan to cover the payment of taxes currently due on the exercise of SARs.

F5: The sales reported in this Form 4 were effected pursuant to Rule 10b5-1 trading plan adopted by the reporting person on November 1, 2011.

F6: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $31.48 to $32.33, 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 (6) to this Form 4.

F7: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $32.02 to $32.92, 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 (7) to this Form 4.