X0508 4 2026-02-19 0001262823 WESTLAKE CORP WLK 0002021323 Holy Jeffrey Adam 2801 POST OAK BLVD., SUITE 600 HOUSTON TX 77056 false true false false VP and CAO false Common Stock 2026-02-19 4 A false 264 0 A 5205 D Common Stock 2026-02-20 4 F false 81 94.10 D 5124 D Employee Option (right to buy) 94.48 2026-02-20 4 A false 4394 0 A 2036-02-20 Common Stock 4394 4394 D Restricted Stock Units 2026-02-20 4 A false 1199 0 A Common Stock 1199 1199 D Restricted Stock Units 2026-02-20 4 A false 2540 0 A Common Stock 2540 2540 D Represents shares of common stock that vested on February 19, 2026, upon the determination by the Compensation Committee of the Issuer's Board of Directors of the satisfaction of performance criteria underlying an award of performance stock units ("PSUs") granted to the Reporting Person on February 17, 2023, under the terms of the Issuer's 2013 Omnibus Incentive Plan. Shares otherwise issuable were witheld to satisfy tax obligations arising out of vesting of the Reporting Person's PSUs. The stock options are excercisable in three installments of 33%, 33% and 34% on February 20, 2027, 2028 and 2029, respectively. Each restricted stock unit ("RSU") represents a contingent right to recieve one share of the Issuer's common stock. All of the RSUs will vest on February 20, 2029. Jeffrey A. Holy by J. Feng, POA 2026-02-23