X0305 4 2012-06-21 0001069878 TREX CO INC TREX 0001463613 Cox James Mitchell C/O TREX COMPANY, INC 160 EXETER DRIVE WINCHESTER VA 22603-8605 1 Vice President, Sales Common Stock 2012-06-21 4 F 0 2831 29.87 D 125403 D Common Stock 2012-06-21 4 D 0 6056 29.87 D 119347 D On June 21, 2012, the Reporting Person's employment with the Company ended. Pursuant to a Severance Agreement between the Reporting Person and the Company, a total of 6,868 restricted shares otherwise scheduled to vest on February 15, 16 and 17, 2013 were accelerated, resulting in 2,831 shares being surrendered as allowed by the Company's 2005 Stock Incentive Plan to cover the payment of taxes currently due on these vested restricted shares. A total of 6,056 unvested restricted shares are being forfeited by the Reporting Person under the terms of the Company's 2005 Stock Incentive Plan. /s/ William R. Gupp by power of attorney 2012-06-22