X0306 4 2020-02-17 0 0001262823 WESTLAKE CHEMICAL CORP WLK 0001439749 Kenner Andrew 2801 POST OAK BOULEVARD, SUITE 600 HOUSTON TX 77056 0 1 0 0 SVP - Chemical Manufacturing Common Stock 2020-02-17 4 M 0 2647 A 18115 D Common Stock 2020-02-18 4 F 0 754 60.528 D 17361 D Restricted Stock Units 2020-02-17 4 M 0 2647 0 D Common Stock 2647 00 D Restricted stock units convert into Issuer's shares of common stock on a one-for-one basis. On February 17, 2017, the reporting person was granted 2,647 restricted stock units vesting on the third anniversary of the grant date. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $60.50 to $60.946, inclusive. The reporting person undertakes to provide to Westlake Chemical Corp., any security holder of Westlake Chemical Corp. or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote. Andrew Kenner by J. Feng POA 2020-02-19