X0306 4 2017-12-04 0 0001262823 WESTLAKE CHEMICAL CORP WLK 0001330417 Bender Mark Steven 2801 POST OAK BOULEVARD, SUITE 600 HOUSTON TX 77056 0 1 0 0 EVP and CFO Common Stock 2017-12-04 4 M 0 6500 22.915 A 30567 D Common Stock 2017-12-04 4 S 0 6500 97.831 D 24067 D Employee Option (right to buy) 22.915 2017-12-04 4 M 0 6500 0 A 2021-02-18 Common Stock 6500 6680 D The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $97.35 to $98.17, 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. The stock options are excercisable in three installments of 33%, 33% and 34% on February 18, 2012, 2013 and 2014. M. Steven Bender by J. Feng POA 2017-12-05