TREX CO INC

Ticker: TREX CUSIP: 89531P105 Class: Common Stock

PRIMECAP MANAGEMENT CO/CA/'s Holding History (CIK: 0000763212)

Note: Option positions (PUT/CALL) are excluded.

Q4 2015

Shares 188,100 Value ($000) $7,155 Avg Close $10.02 Range $8.43 - $11.04

Q3 2015

Shares 188,100 Value ($000) $6,269 Avg Close $10.27 Range $7.93 - $12.54

Q2 2015

Shares 187,037 Value ($000) $9,245 Avg Close $12.82 Range $11.68 - $14.43

Q1 2015

Shares 183,337 Value ($000) $9,997 Avg Close $11.54 Range $9.51 - $13.78

Q4 2014

Shares 183,337 Value ($000) $7,806 Avg Close $9.96 Range $7.77 - $11.21

Q3 2014

Shares 183,337 Value ($000) $6,338 Avg Close $8.38 Range $6.29 - $9.87

Period	Shares	Value ($000)	Average Close	Price Range
Q4 2015	188,100	$7,155	$10.02	$8.43 - $11.04
Q3 2015	188,100	$6,269	$10.27	$7.93 - $12.54
Q2 2015	187,037	$9,245	$12.82	$11.68 - $14.43
Q1 2015	183,337	$9,997	$11.54	$9.51 - $13.78
Q4 2014	183,337	$7,806	$9.96	$7.77 - $11.21
Q3 2014	183,337	$6,338	$8.38	$6.29 - $9.87