Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
Posey Richard E
  2. Issuer Name and Ticker or Trading Symbol
TREX CO INC [TREX]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director _____ 10% Owner
_____ Officer (give title below) _____ Other (specify below)
(Last)
(First)
(Middle)
C/O TREX COMPANY, INC., 160 EXETER DRIVE
3. Date of Earliest Transaction (Month/Day/Year)
05/11/2015
(Street)

WINCHESTER, VA 22603-8605
4. If Amendment, Date Original Filed(Month/Day/Year)
6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)
2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)
4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)
5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)
6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)
7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price
Common Stock 05/11/2015   M   812 A $ 10.7 10,772 D  
Common Stock 05/11/2015   M   1,206 A $ 8.54 11,978 D  
Common Stock 05/11/2015   M   656 A $ 6.53 12,634 D  
Common Stock 05/11/2015   M   884 A $ 10.225 13,518 D  
Common Stock 05/11/2015   M   990 A $ 10.12 14,508 D  
Common Stock 05/11/2015   M   1,052 A $ 7.43 15,560 D  
Common Stock 05/11/2015   D   988 D $ 50.86 14,572 D  
Common Stock 05/12/2015   S   100 D $ 49.36 14,472 D  
Common Stock 05/12/2015   S   300 D $ 49.39 14,172 D  
Common Stock 05/12/2015   S   100 D $ 49.4225 14,072 D  
Common Stock 05/12/2015   S   500 D $ 49.43 13,572 D  
Common Stock 05/12/2015   S   300 D $ 49.44 13,272 D  
Common Stock 05/12/2015   S   200 D $ 49.52 13,072 D  
Common Stock 05/12/2015   S   200 D $ 49.5325 12,872 D  
Common Stock 05/12/2015   S   400 D $ 49.72 12,472 D  
Common Stock 05/12/2015   S   200 D $ 49.76 12,272 D  
Common Stock 05/12/2015   S   100 D $ 49.88 12,172 D  
Common Stock 05/12/2015   S   300 D $ 49.89 11,872 D  
Common Stock 05/12/2015   S   300 D $ 49.99 11,572 D  
Common Stock 05/12/2015   S   300 D $ 50.0301 11,272 D  
Common Stock 05/12/2015   S   200 D $ 50.29 11,072 D  
Common Stock 05/12/2015   S   300 D $ 50.3 10,772 D  
Common Stock 05/12/2015   S   100 D $ 50.31 10,672 D  
Common Stock 05/12/2015   S   100 D $ 50.315 10,572 D  
Common Stock 05/12/2015   S   612 D $ 50.41 9,960 D  

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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)
2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)
5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)
6. Date Exercisable and Expiration Date
(Month/Day/Year)
7. Title and Amount of Underlying Securities
(Instr. 3 and 4)
8. Price of Derivative Security
(Instr. 5)
9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)
10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)
11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Stock Appreciation Right $ 10.7 05/11/2015   M     812 04/01/2010 04/01/2020 Common Stock 812 $ 0 0 D  
Stock Appreciation Right $ 8.54 05/11/2015   M     1,206 10/01/2009 10/01/2019 Common Stock 1,206 $ 0 0 D  
Stock Appreciation Right $ 6.53 05/11/2015   M     656 07/01/2009 07/01/2019 Common Stock 656 $ 0 0 D  
Stock Appreciation Right $ 10.225 05/11/2015   M     884 07/01/2010 07/01/2020 Common Stock 884 $ 0 0 D  
Stock Appreciation Right $ 10.12 05/11/2015   M     990 01/04/2010 01/04/2020 Common Stock 990 $ 0 0 D  
Stock Appreciation Right $ 7.43 05/11/2015   M     1,052 07/21/2009 07/21/2019 Common Stock 1,052 $ 0 0 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
Posey Richard E
C/O TREX COMPANY, INC.
160 EXETER DRIVE
WINCHESTER, VA 22603-8605
  X      

Signatures

 /s/ William R. Gupp by power of attorney   05/13/2015
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

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