Westlake director exercises 2,168 RSUs into stock

WESTLAKE CORP director David Tsung-Hung Chao reported the vesting and conversion of 2,168 restricted stock units into an equal number of common shares on August 8, 2026.

Rhea-AI Filing Summary

WESTLAKE CORP director David Tsung-Hung Chao reported the vesting and conversion of 2,168 restricted stock units into an equal number of common shares on August 8, 2026. Following this exercise, he holds 11,080 common shares directly and 19,423 common shares indirectly through a trust for his benefit, where he serves as sole trustee.

Insider Trade Summary

2,168 shares exercised/converted

Exercise 3 txns

Insider Chao David Tsung-Hung

Role Director

Type	Security	Shares	Price	Value
Exercise	Restricted Stock Units F1, F3	2,168	$0.00	$0.00
Exercise	Common Stock F1	2,168	--	--
holding	Common Stock F2	--	--	--

Holdings After Transaction: Restricted Stock Units — 2,168 contracts (Direct); Common Stock — 11,080 shares (Direct); Common Stock — 19,423 shares (Indirect, by Trust)

Footnotes (3)

1. F1. Restricted stock units convert into the Issuer's common stock on a one-for-one basis.
2. F2. These shares are held in a trust for the benefit of the reporting person, who also serves as sole trustee.
3. F3. On August 8, 2025 the reporting person was granted 2,168 restricted stock units vesting on the first anniversary of the grant date.

Key Figures

Restricted stock units exercised: 2,168 units Common shares acquired: 2,168 shares Direct common share holdings: 11,080 shares +2 more

5 metrics

Restricted stock units exercised 2,168 units RSUs converted into common stock on August 8, 2026

Common shares acquired 2,168 shares Shares received from RSU conversion

Direct common share holdings 11,080 shares Direct ownership after the reported transactions

Indirect trust holdings 19,423 shares Common stock held indirectly by trust for reporting person

RSU grant size 2,168 units Restricted stock units granted on August 8, 2025

Key Terms

Restricted stock units, derivative security, indirect ownership, trust

4 terms

Restricted stock units financial

"Restricted stock units convert into the Issuer's common stock on a one-for-one basis."

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

derivative security financial

"Transaction code M is described as Exercise or conversion of derivative security."

A derivative security is a financial contract whose value comes from the price or performance of something else, such as a stock, bond, commodity, or market index. For investors it acts like an insurance policy or a wager: it can be used to protect against losses, lock in prices, or amplify gains and losses, so it can change a portfolio’s risk and potential return without owning the underlying asset directly.

indirect ownership financial

"Common Stock held indirectly with nature of ownership noted as by Trust."

trust financial

"These shares are held in a trust for the benefit of the reporting person."

A trust is a legal setup in which one party (the trustee) holds and manages assets—like cash, stocks or property—on behalf of other people (beneficiaries) according to instructions from the person who created it (the grantor). Think of it as a locked box with a keyholder who must follow written rules; for investors it matters because trusts influence who controls and benefits from assets, affect taxes and succession, and can change how quickly or transparently shares are bought, sold or voted.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What transaction did Westlake Corp (WLK) director David Tsung-Hung Chao report?

Director David Tsung-Hung Chao reported the exercise of 2,168 restricted stock units into common stock on August 8, 2026. The units converted one-for-one into Westlake Corp common shares.

How many Westlake Corp (WLK) shares did David Tsung-Hung Chao acquire in this Form 4?

He acquired 2,168 common shares through the conversion of restricted stock units. The filing states the restricted stock units convert into the issuer’s common stock on a one-for-one basis.

What are David Tsung-Hung Chao’s Westlake Corp (WLK) direct holdings after the transaction?

After the transaction, David Tsung-Hung Chao directly holds 11,080 common shares of Westlake Corp. This figure reflects the addition of 2,168 shares received from vested restricted stock units.

How many Westlake Corp (WLK) shares does David Tsung-Hung Chao hold through a trust?

He indirectly holds 19,423 common shares through a trust. The trust is for his benefit, and he serves as sole trustee, as disclosed in the filing footnote.

What do the restricted stock unit (RSU) terms disclose for Westlake Corp (WLK)?

The filing notes that restricted stock units convert into common stock on a one-for-one basis. It also states that 2,168 RSUs were granted on August 8, 2025, vesting on the first anniversary of the grant date.

Was David Tsung-Hung Chao’s Westlake Corp (WLK) transaction under a Rule 10b5-1 plan?

The Form 4 indicates the Rule 10b5-1 checkbox is not marked, so these transactions are not reported as executed under a Rule 10b5-1 trading plan according to the filing data.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 08/10/2026 - 01:50 PM EDT Learn about SEC filing dates

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^*

Chao David Tsung-Hung

(Last) (First) (Middle)

2801 POST OAK BLVD., STE. 600

(Street)

HOUSTON TEXAS 77056

(City) (State) (Zip)

UNITED STATES

(Country)

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
	Officer (give title below)		Other (specify below)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
08/08/2026

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	08/08/2026		M		2,168	A	(1)	11,080	D
Common Stock								19,423	I	by Trust(2)

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
Restricted Stock Units	(1)	08/08/2026		M			2,168	(3)	(3)	Common Stock	2,168	$0	2,168	D

Explanation of Responses:

1. Restricted stock units convert into the Issuer's common stock on a one-for-one basis.

2. These shares are held in a trust for the benefit of the reporting person, who also serves as sole trustee.

3. On August 8, 2025 the reporting person was granted 2,168 restricted stock units vesting on the first anniversary of the grant date.

	David Chao by J Feng POA	08/10/2026
	** 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)