Westlake Corp (WLK) chair exercises options and sells common stock

Rhea-AI Filing Summary

Westlake Corp’s executive chairman and director reported an option exercise and share sales in the company’s common stock. On 12/22/2025, he exercised an employee stock option to acquire 81,673 shares of common stock at an exercise price of $44.42 per share, increasing his direct holdings.

That same day, he sold shares in several open-market transactions, including 9,711 shares at a weighted average price of $72.818, 30,604 shares at a weighted average price of $73.796, and 521 shares at a weighted average price of $74.443. A portion of the sale proceeds was used to pay the option strike price and related taxes. After these transactions, he directly owned 627,722 shares of Westlake Corp common stock, and the reported option position was reduced to zero.

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

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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^*

Chao Albert

(Last) (First) (Middle)

2801 POST OAK BLVD., STE. 600

(Street)

HOUSTON TX 77056

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
WESTLAKE CORP [ WLK ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Executive Chairman

3. Date of Earliest Transaction (Month/Day/Year)
12/22/2025

4. If Amendment, Date of 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

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	12/22/2025		M		81,673	A	$44.42	668,558	D
Common Stock	12/22/2025		S(1)		9,711	D	$72.818(2)	658,847	D
Common Stock	12/22/2025		S(1)		30,604	D	$73.796(3)	628,243	D
Common Stock	12/22/2025		S(1)		521	D	$74.443(4)	627,722	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
Employee Option (right to buy)	$44.42	12/22/2025		M			81,673	(5)	02/18/2026	Common Stock	81,673	$0	0	D

Explanation of Responses:

1. A portion of the sale proceeds were used to cover the strike price and related taxes in regards to the excercise of the options disclosed in Table II.

2. Weighted average price. These shares were sold in multiple transactions ranging from $72.395 to $73.39 inclusive. The reporting person undertakes to provide the issuer, any security holder of the issuer, or the staff of the SEC, upon request, full information regarding the number of shares sold at each separate price within the range set forth above.

3. Weighted average price. These shares were sold in multiple transactions ranging from $73.40 to $74.40 inclusive. The reporting person undertakes to provide the issuer, any security holder of the issuer, or the staff of the SEC, upon request, full information regarding the number of shares sold at each separate price within the range set forth above.

4. Weighted average price. These shares were sold in multiple transactions ranging from $74.405 to $74.515 inclusive. The reporting person undertakes to provide the issuer, any security holder of the issuer, or the staff of the SEC, upon request, full information regarding the number of shares sold at each separate price within the range set forth above.

5. The stock options are exercisable in three installments of 33%, 33% and 34% on February 18, 2017, 2018 and 2019, respectively.

	Albert Chao by J Feng POA	12/23/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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FAQ

What insider transaction did Westlake Corp (WLK) report in this Form 4?

The filing reports that Westlake Corp’s executive chairman and director exercised an employee stock option for 81,673 shares of common stock at $44.42 per share on 12/22/2025, and sold portions of the acquired stock in multiple market transactions the same day.

How many Westlake Corp (WLK) shares did the insider sell and at what prices?

On 12/22/2025, the insider sold 9,711 shares at a weighted average price of $72.818, 30,604 shares at a weighted average price of $73.796, and 521 shares at a weighted average price of $74.443. Each weighted average price covers multiple trades within the price ranges described in the notes.

How many Westlake Corp (WLK) shares does the reporting person own after these transactions?

Following the reported option exercise and share sales on 12/22/2025, the executive chairman directly owned 627,722 shares of Westlake Corp common stock.

What happened to the stock options reported by the Westlake Corp (WLK) insider?

The insider exercised an employee stock option covering 81,673 shares of common stock at $44.42 per share. After this exercise, the number of derivative securities (the option) reported as beneficially owned was zero. The option was originally scheduled to vest in three installments of 33%, 33% and 34% in 2017, 2018 and 2019 and had an expiration date of 02/18/2026.

Did the Westlake Corp (WLK) insider use sale proceeds for option costs or taxes?

Yes. The explanation states that a portion of the sale proceeds from the reported stock sales was used to cover the option strike price and related taxes associated with the option exercise disclosed in Table II.

What role does the reporting person hold at Westlake Corp (WLK)?

The reporting person is identified as both a director and an officer, serving as Executive Chairman of Westlake Corp.