Sec Form 4/A Filing - Chao John Tsung-chen @ WESTLAKE CORP - 2025-03-05

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

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, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL OMB Number: 3235-0287 Expires: November 30, 2011 Estimated average burden hours per response... 0.5

1. Name and Address of Reporting Person Chao John Tsung-chen 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) (Last) (First) (Middle) 2801 POST OAK BLVD., STE. 600 3. Date of Earliest Transaction (MM/DD/YY) 03/05/2025 (Street) HOUSTON, TX77056 4. If Amendment, Date Original Filed (MM/DD/YY) 02/20/2025 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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 02/18/2025 M 513 A $ 0 6,709 D Common Stock 03/05/2025 F 235 ( 1 ) D $ 108.62 7,429 ( 2 ) 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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 7. Title and Amount of Underlying Securities (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 of Derivative Security: 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

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Chao John Tsung-chen 2801 POST OAK BLVD., STE. 600 HOUSTON, TX77056 X Signatures John Chao by J Feng POA 03/06/2025 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The original Form 4 filed by the Reporting Person on February 20, 2025 is amended by this Form 4A to disclose that 235 shares of common stock were sold to satisfy tax obligations arising out of the vesting of the reporting persons Restricted Stock Units. The original Form 4 did not report the sale to cover tax withholding obligations because the number of shares to be sold was not known at the time of filing. This Form 4A is in addition to, and does not replace, the disclosure contained in the original Form 4. ( 2 )The amount of common stock beneficially owned by the Reporting Person relfects adjustments for subsquent transactions reported on February 24, 2025 and reflects the total owned subsquent to the tax witholding obligation of 235 shares.

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.