X0508 4 2026-02-24 0001069878 TREX CO INC TREX 0001987902 Fernandez Amy M. C/O TREX COMPANY, INC. 2500 TREX WAY WINCHESTER VA 22601 1 SVP, CLO and Secretary 0 Common Stock 2026-02-24 4 A 0 10181 41.45 A 62332 D Common Stock 2026-02-24 4 A 0 10181 41.45 A 72513 D This restricted stock unit award vests over a three-year period in three equal annual installments occurring March 1, 2027, March 1, 2028, and March 1, 2029. This restricted stock unit award is performance-based, and vests over a three-year period in three equal installments occurring March 1, 2027, March 1, 2028, and March 1, 2029. The number of shares set forth above is the target number of shares. The number of shares that will actually vest each year will be based upon performance against certain financial goals for the Company and will range from 0% to 200% of the target number of shares. /s/ Amy M. Fernandez 2026-02-25