# EDGAR Filing Document

**Accession Number:** 0001069878
**File Stem:** 0001069878-26-000040
**Filing Date:** 2026-5
**Character Count:** 6695
**Document Hash:** daac6211b83d52a697fe946f0139f19f
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001069878-26-000040.hdr.sgml**: 20260506

**ACCESSION NUMBER**: 0001069878-26-000040

**CONFORMED SUBMISSION TYPE**: 3

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20260428

**FILED AS OF DATE**: 20260506

**DATE AS OF CHANGE**: 20260506

**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Lauer Zachary C.
- **CENTRAL INDEX KEY:** 0002132943

**ORGANIZATION NAME:**

**FILING VALUES:**
- **FORM TYPE:** 3
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-14649
- **FILM NUMBER:** 26947556

**MAIL ADDRESS:**
- **STREET 1:** 2500 TREX WAY
- **STREET 2:** C/O TREX COMPANY, INC.
- **CITY:** WINCHESTER
- **STATE:** VA
- **ZIP:** 22601
**ISSUER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** TREX CO INC
- **CENTRAL INDEX KEY:** 0001069878
- **STANDARD INDUSTRIAL CLASSIFICATION:** LUMBER & WOOD PRODUCTS (NO FURNITURE) [2400]
- **ORGANIZATION NAME:** 04 Manufacturing
- **EIN:** 541910453
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**BUSINESS ADDRESS:**
- **STREET 1:** 2500 TREX WAY
- **CITY:** WINCHESTER
- **STATE:** VA
- **ZIP:** 22601
- **BUSINESS PHONE:** 5405426300

**MAIL ADDRESS:**
- **STREET 1:** 2500 TREX WAY
- **CITY:** WINCHESTER
- **STATE:** VA
- **ZIP:** 22601

### UNITED STATES SECURITIES AND EXCHANGE COMMISSION
**Washington, D.C. 20549**

## FORM 3

### INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

[ ] Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Lauer Zachary C.<br><sub>(Last) (First) (Middle)</sub><br>2500 TREX WAY<br>C/O TREX COMPANY, INC.<br><sub>(Street)</sub><br>WINCHESTER, VA 22601<br><sub>(City) (State) (Zip)</sub> | **3. Issuer Name and Ticker or Trading Symbol**<br>TREX CO INC [ TREX ] | **5. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  |
| **2. Date of Event Requiring Statement (Month/Day/Year)**<br>2026-04-28 | **4. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[ ] Director   [ ] 10% Owner<br>[X] Officer (give title below)   [ ] Other (specify below)<br>_SVP, Chief Operations Officer_ | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[X] Form filed by One Reporting Person<br>[ ] Form filed by More than One Reporting Person |

---

## Table I - Non-Derivative Securities Beneficially Owned

---

|  |  |  |  |
| --- | --- | --- | --- |
| 1. Title of Security | 2. Amount of Securities Beneficially Owned | 3. Ownership Form | 4. Nature of Indirect Beneficial Ownership |
| Common Stock | 28187<sup>(1)</sup> | D |  |

---

## Table II - Derivative Securities Beneficially Owned

---

|  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Derivative Security | 2. Date Exercisable and Expiration Date (Month/Day/Year) | 2. Date Exercisable and Expiration Date (Month/Day/Year) | 3. Title and Amount of Underlying Securities | 3. Title and Amount of Underlying Securities | 4. Conversion or Exercise Price | 5. Ownership Form | 6. Nature of Indirect Beneficial Ownership |
| 1. Title of Derivative Security | Date Exercisable | Expiration Date | Title | Amount or Number of Shares | 4. Conversion or Exercise Price | 5. Ownership Form | 6. Nature of Indirect Beneficial Ownership |
| Stock Appreciation Right | 2023-02-19<sup>(2)</sup> | 2030-02-19 | Common Stock | 2166 | $50.83 | D |  |
| Stock Appreciation Right | 2024-02-17<sup>(3)</sup> | 2031-02-17 | Common Stock | 810 | $104.56 | D |  |
| Stock Appreciation Right | 2025-03-01<sup>(4)</sup> | 2032-02-23 | Common Stock | 1338 | $82.01 | D |  |
| Stock Appreciation Right | 2026-03-01<sup>(5)</sup> | 2033-02-14 | Common Stock | 2152 | $56.80 | D |  |
| Stock Appreciation Right | 2027-03-01<sup>(6)</sup> | 2034-02-19 | Common Stock | 1522 | $90.86 | D |  |
| Stock Appreciation Right | 2028-03-01<sup>(7)</sup> | 2035-02-17 | Common Stock | 2481 | $67.33 | D |  |

---

### Footnotes:

(1) Includes 3,848 time-based restricted stock units that vest March 1, 2027; 3,264 time-based restricted stock units that vest March 1, 2028; 2,304 time-based restricted stock units that vest March 1, 2029; a target number of 4,509 performance-based restricted stock units that vest on March 1, 2027; a target number of 3,675 performance-based restricted stock units that vest on March 1, 2028; and a target number of 2,304 performance-based restricted stock units that vest on March 1, 2029. The number of performance-based restricted stock units set forth above is the target number of shares. The number of shares that will actually vest 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.

(2) This stock appreciation right became exercisable in three equal installments that occurred on February 19, 2021, February 19, 2022, and February 19, 2023.

(3) This stock appreciation right became exercisable in three equal installments that occurred on February 17, 2022, February 17, 2023, and February 17, 2024.

(4) This stock appreciation right became exercisable in three equal installments that occurred on March 1, 2023, March 1, 2024, and March 1, 2025.

(5) This stock appreciation right became exercisable in three equal installments that occurred on March 1, 2024, March 1, 2025, and March 1, 2026.

(6) This stock appreciation right vests in three equal annual installments; the first and second installments became exercisable on March 1, 2025 and March 1, 2026, respectively, and the third installment will become exercisable on March 1, 2027.

(7) This stock appreciation right vests in three equal annual installments; the first installment became exercisable on March 1, 2026, and the second and third installments will become exercisable on March 1, 2027 and March 1, 2028, respectively.

**Signature:** /s/ Amy M. Fernandez by power of attorney  
**Date:** 2026-05-06

### Remarks:

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* 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).

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

**Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.**