X0306 4 2020-03-19 0 0001262823 WESTLAKE CHEMICAL CORP WLK 0001299599 TTWFGP LLC 2801 POST OAK BOULEVARD, SUITE 600 HOUSTON TX 77056 0 0 1 0 Common Stock 2020-03-19 4 P 0 3002 35.23 A 46658279 I See Footnote Common Stock 2020-03-19 4 P 0 22497 36.20 A 46680776 I See Footnote Common Stock 2020-03-18 4 P 0 63336 37.32 A 46744112 I See Footnote Common Stock 2020-03-19 4 P 0 54388 38.22 A 46798500 I See Footnote Common Stock 2020-03-19 4 P 0 21777 39.09 A 46820277 I See Footnote The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $34.69 to $35.69, 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 purchased at each separate price within the ranges set forth in this footnote. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $35.71 to $36.65, 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 purchased at each separate price within the ranges set forth in this footnote. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $36.75 to $37.75, 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 purchased at each separate price within the ranges set forth in this footnote. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $37.77 to $38.77, 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 purchased at each separate price within the ranges set forth in this footnote. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $38.78 to $39.77, 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 purchased at each separate price within the ranges set forth in this footnote. TTWFGP LLC is the general partner of TTWF LP, the record holder of the securities listed in Table 1. Reporting Person has no direct pecuniary interest in the securities in Table 1. Reporting Person may be deemed to beneficially own an indirect pecuniary interest in the securities in Table 1. TTWFGP LLC by J. Feng, POA 2020-03-20