[Form 4] TREX CO INC Insider Trading Activity

Rhea-AI Filing Summary

Trex Co Inc director David Christian Keffer reported receiving a stock-based compensation award rather than making an open-market trade. On April 1, 2026, he acquired 175 shares of Common Stock at an indicated value of $36.57 per share as a grant or award.

The filing notes this restricted stock unit award will vest on the first anniversary of the grant, meaning the shares are subject to a one-year vesting period before fully earned. After this award, Keffer directly holds 3,424 Trex shares, reflecting a relatively small, routine director compensation grant.

Insider Trade Summary

1 transaction reported

Mixed 1 txn

Insider Keffer David Christian

Role Director

Type	Security	Shares	Price	Value
Grant/Award	Common Stock	175	$36.57	$6K

Holdings After Transaction: Common Stock — 3,424 shares (Direct)

Footnotes (1)

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Key Figures

Shares granted: 175 shares Grant price: $36.57 per share Shares owned after grant: 3,424 shares

3 metrics

Shares granted 175 shares Restricted stock unit award on April 1, 2026

Grant price $36.57 per share Value used for the April 1, 2026 award

Shares owned after grant 3,424 shares Total direct Trex holdings following the transaction

Key Terms

restricted stock unit award, Common Stock, Grant, award, or other acquisition

3 terms

restricted stock unit award financial

"This restricted stock unit award will vest on the first anniversary"

A restricted stock unit award is a promise by a company to give an employee a specified number of company shares at a future date if certain conditions are met, such as staying with the company or hitting performance goals. For investors, these awards matter because they can increase the total number of shares outstanding when converted, diluting existing holders, and they align employees’ incentives with shareholders’ interests much like giving a rising bonus that becomes real only after conditions are satisfied.

Common Stock financial

"security_title: "Common Stock""

Common stock represents ownership shares in a company, giving investors a stake in its success and a say in important decisions through voting rights. It is the most common type of stock traded on markets and can provide income through dividends, as well as potential for value growth. For investors, holding common stock means sharing in the company’s profits and risks.

Grant, award, or other acquisition financial

"transaction_code_description: "Grant, award, or other acquisition""

Form 4 Insider Transactions: What Each Field Means →

SEC Form 4

FORM 4

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

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

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

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Keffer David Christian

(Last) (First) (Middle)

2500 TREX WAY

C/O TREX COMPANY, INC.

(Street)

WINCHESTER VIRGINIA 22601

(City) (State) (Zip)

UNITED STATES

(Country)

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)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
04/01/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

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	04/01/2026		A(1)		175	A	$36.57	3,424	D

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 Securities Underlying Derivative Security (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: 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

Explanation of Responses:

1. This restricted stock unit award will vest on the first anniversary of the grant.

	/s/ Amy M. Fernandez by power of attorney	04/03/2026
	** Signature of Reporting Person	Date
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.
* Form 4: SEC 1474 (03-26)