TTWFGP LLC

SEC source: 0001567619-20-007143 · doc1.xml · nonDerivative · entry 4

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 47,400,277

F4 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $40.01 to $40.60, 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.

F5 · ownership.nature: 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.

SEC source: 0001567619-20-007143 · doc1.xml · nonDerivative · entry 3

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 47,388,990

F3 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $39.00 to $40.00, 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.

F5 · ownership.nature: 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.

SEC source: 0001567619-20-007143 · doc1.xml · nonDerivative · entry 2

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 47,299,547

F2 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $37.99 to $38.99, 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.

F5 · ownership.nature: 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.

SEC source: 0001567619-20-007143 · doc1.xml · nonDerivative · entry 1

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 47,257,252

F1 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $36.98 to $37.98, 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.

F5 · ownership.nature: 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.

SEC source: 0001567619-20-015789 · doc1.xml · nonDerivative · entry 9

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 1,395,000

F11 · price: Reflects the average price of shares purchased March 27, 2020. Each line in Table I of the original Form 4, filed March 30, 2020, correctly aggregated purchases within a $1.00 price range.

F2 · balance_after: Amended to reflect total direct ownership of Issuer shares as of the original Form 4 filing date. Purchases reported on and after March 16, 2020 were erroneously added to existing indirect holdings. These indirect holdings of 46,005,227 (which correspond to a post stock-split total of 92,010,554 shares) are owned by TTWF LP and further described by footnote 12 below.

F3 · ownership.direct: Erroneously reported as indirect holdings. Amended to reflect direct ownership.

SEC source: 0001567619-20-007073 · doc1.xml · nonDerivative · entry 3

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 47,240,277

F3 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $41.79 to $42.13, 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.

F4 · ownership.nature: 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.

SEC source: 0001567619-20-007073 · doc1.xml · nonDerivative · entry 2

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 47,231,477

F2 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $40.78 to $41.78, 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.

F4 · ownership.nature: 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.

SEC source: 0001567619-20-007073 · doc1.xml · nonDerivative · entry 1

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 47,137,476

F1 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $39.77 to $40.77, 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.

F4 · ownership.nature: 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.

SEC source: 0001567619-20-015789 · doc1.xml · nonDerivative · entry 8

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 1,235,000

F10 · price: Reflects the average price of shares purchased March 26, 2020. The original Form 4, filed March 27, 2020, provides weighted average pricing for each transaction within a $1.00 threshold in column 4 and related footnotes.

F2 · balance_after: Amended to reflect total direct ownership of Issuer shares as of the original Form 4 filing date. Purchases reported on and after March 16, 2020 were erroneously added to existing indirect holdings. These indirect holdings of 46,005,227 (which correspond to a post stock-split total of 92,010,554 shares) are owned by TTWF LP and further described by footnote 12 below.

F3 · ownership.direct: Erroneously reported as indirect holdings. Amended to reflect direct ownership.

SEC source: 0001567619-20-007010 · doc1.xml · nonDerivative · entry 6

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 47,095,277

F6 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $42.45 to $43.03, 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.

F7 · ownership.nature: 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.

SEC source: 0001567619-20-007010 · doc1.xml · nonDerivative · entry 5

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 47,071,213

F5 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $41.44 to $42.44, 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.

F7 · ownership.nature: 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.

SEC source: 0001567619-20-007010 · doc1.xml · nonDerivative · entry 4

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 47,037,855

F4 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $40.43 to $41.43, 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.

F7 · ownership.nature: 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.

SEC source: 0001567619-20-007010 · doc1.xml · nonDerivative · entry 3

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 47,023,830

F3 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $39.38 to $40.33, 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.

F7 · ownership.nature: 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.

SEC source: 0001567619-20-007010 · doc1.xml · nonDerivative · entry 2

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 46,996,159

F2 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $38.37 to $39.37, 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.

F7 · ownership.nature: 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.

SEC source: 0001567619-20-007010 · doc1.xml · nonDerivative · entry 1

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 46,971,928

F1 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $37.34 to $38.32, 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.

F7 · ownership.nature: 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.

SEC source: 0001567619-20-015789 · doc1.xml · nonDerivative · entry 7

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 1,090,000

F9 · price: Reflects the average price of shares purchased March 25, 2020. Each line in Table I of the original Form 4, filed March 26, 2020, correctly aggregated purchases within a $1.00 price range.

F2 · balance_after: Amended to reflect total direct ownership of Issuer shares as of the original Form 4 filing date. Purchases reported on and after March 16, 2020 were erroneously added to existing indirect holdings. These indirect holdings of 46,005,227 (which correspond to a post stock-split total of 92,010,554 shares) are owned by TTWF LP and further described by footnote 12 below.

F3 · ownership.direct: Erroneously reported as indirect holdings. Amended to reflect direct ownership.

SEC source: 0001567619-20-006977 · doc1.xml · nonDerivative · entry 4

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 46,965,277

F4 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $37.43 to $37.87, 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.

F5 · ownership.nature: 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.

SEC source: 0001567619-20-006977 · doc1.xml · nonDerivative · entry 3

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 46,950,246

F3 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $36.42 to $37.42, 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.

F5 · ownership.nature: 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.

SEC source: 0001567619-20-006977 · doc1.xml · nonDerivative · entry 2

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 46,882,434

F2 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $35.41 to $36.41, 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.

F5 · ownership.nature: 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.

SEC source: 0001567619-20-006977 · doc1.xml · nonDerivative · entry 1

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 46,825,015

F1 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $34.30 to $35.30, 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.

F5 · ownership.nature: 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.

SEC source: 0001567619-20-015789 · doc1.xml · nonDerivative · entry 6

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 960,000

F8 · price: Reflects the average price of shares purchased March 24, 2020. Each line in Table I of the original Form 4, filed March 25, 2020, correctly aggregated purchases within a $1.00 price range.

F2 · balance_after: Amended to reflect total direct ownership of Issuer shares as of the original Form 4 filing date. Purchases reported on and after March 16, 2020 were erroneously added to existing indirect holdings. These indirect holdings of 46,005,227 (which correspond to a post stock-split total of 92,010,554 shares) are owned by TTWF LP and further described by footnote 12 below.

F3 · ownership.direct: Erroneously reported as indirect holdings. Amended to reflect direct ownership.

SEC source: 0001567619-20-006808 · doc1.xml · nonDerivative · entry 5

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 46,820,277

F5 · price: 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.

F6 · ownership.nature: 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.

SEC source: 0001567619-20-006808 · doc1.xml · nonDerivative · entry 4

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 46,798,500

F4 · price: 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.

F6 · ownership.nature: 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.

SEC source: 0001567619-20-006808 · doc1.xml · nonDerivative · entry 2

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 46,680,776

F2 · price: 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.

F6 · ownership.nature: 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.

SEC source: 0001567619-20-006808 · doc1.xml · nonDerivative · entry 1

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 46,658,279

F1 · price: 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.

F6 · ownership.nature: 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.

SEC source: 0001567619-20-015789 · doc1.xml · nonDerivative · entry 5

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 815,000

F7 · price: Reflects the average price of shares purchased March 19, 2020 Each line in Table I of the original Form 4, filed March 20, 2020, correctly aggregated purchases within a $1.00 price range.

F2 · balance_after: Amended to reflect total direct ownership of Issuer shares as of the original Form 4 filing date. Purchases reported on and after March 16, 2020 were erroneously added to existing indirect holdings. These indirect holdings of 46,005,227 (which correspond to a post stock-split total of 92,010,554 shares) are owned by TTWF LP and further described by footnote 12 below.

F3 · ownership.direct: Erroneously reported as indirect holdings. Amended to reflect direct ownership.

SEC source: 0001567619-20-006727 · doc1.xml · nonDerivative · entry 4

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 46,655,277

F4 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $32.94 to $33.29, 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.

F5 · ownership.nature: 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.

SEC source: 0001567619-20-006727 · doc1.xml · nonDerivative · entry 3

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 46,652,977

F3 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $31.87 to $32.78, 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.

F5 · ownership.nature: 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.

SEC source: 0001567619-20-006727 · doc1.xml · nonDerivative · entry 2

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 46,616,187

F2 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $30.86 to $31.86, 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.

F5 · ownership.nature: 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.

SEC source: 0001567619-20-006727 · doc1.xml · nonDerivative · entry 1

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 46,516,247

F1 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $29.85 to $30.85, 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.

F5 · ownership.nature: 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.

SEC source: 0001567619-20-006808 · doc1.xml · nonDerivative · entry 3

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 46,744,112

F3 · price: 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.

F6 · ownership.nature: 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.

SEC source: 0001567619-20-015789 · doc1.xml · nonDerivative · entry 4

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 650,000

F6 · price: Reflects the average price of shares purchased March 18, 2020. Each line in Table I of the original Form 4, filed March 19, 2020, correctly aggregated purchases within a $1.00 price range.

F2 · balance_after: Amended to reflect total direct ownership of Issuer shares as of the original Form 4 filing date. Purchases reported on and after March 16, 2020 were erroneously added to existing indirect holdings. These indirect holdings of 46,005,227 (which correspond to a post stock-split total of 92,010,554 shares) are owned by TTWF LP and further described by footnote 12 below.

F3 · ownership.direct: Erroneously reported as indirect holdings. Amended to reflect direct ownership.

SEC source: 0001567619-20-006641 · doc1.xml · nonDerivative · entry 6

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 46,490,277

F6 · ownership.nature: 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.

SEC source: 0001567619-20-006641 · doc1.xml · nonDerivative · entry 5

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 46,490,177

F5 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $34.00 to $34.98, 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.

F6 · ownership.nature: 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.

SEC source: 0001567619-20-006641 · doc1.xml · nonDerivative · entry 4

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 46,447,356

F4 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $32.99 to $33.99, 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.

F6 · ownership.nature: 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.

SEC source: 0001567619-20-006641 · doc1.xml · nonDerivative · entry 3

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 46,378,353

F3 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $31.98 to $32.98, 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.

F6 · ownership.nature: 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.

SEC source: 0001567619-20-006641 · doc1.xml · nonDerivative · entry 2

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 46,337,277

F2 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $30.97 to $31.97, 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.

F6 · ownership.nature: 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.

SEC source: 0001567619-20-006641 · doc1.xml · nonDerivative · entry 1

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 46,334,437

F1 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $29.90 to $30.77, 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.

F6 · ownership.nature: 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.

SEC source: 0001567619-20-015789 · doc1.xml · nonDerivative · entry 3

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 485,000

F5 · price: Reflects the average price of shares purchased March 17, 2020. Each line in Table I of the original Form 4, filed March 18, 2020, correctly aggregated purchases within a $1.00 price range.

F2 · balance_after: Amended to reflect total direct ownership of Issuer shares as of the original Form 4 filing date. Purchases reported on and after March 16, 2020 were erroneously added to existing indirect holdings. These indirect holdings of 46,005,227 (which correspond to a post stock-split total of 92,010,554 shares) are owned by TTWF LP and further described by footnote 12 below.

F3 · ownership.direct: Erroneously reported as indirect holdings. Amended to reflect direct ownership.

SEC source: 0001567619-20-006510 · doc1.xml · nonDerivative · entry 3

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 46,325,277

F3 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $32.41 to $32.82, 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.

F4 · ownership.nature: 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.

SEC source: 0001567619-20-006510 · doc1.xml · nonDerivative · entry 2

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 46,312,952

F2 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $31.40 to $32.40, 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.

F4 · ownership.nature: 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.

SEC source: 0001567619-20-006510 · doc1.xml · nonDerivative · entry 1

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 46,255,749

F1 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $30.39 to $31.39, 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.

F4 · ownership.nature: 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.

SEC source: 0001567619-20-015789 · doc1.xml · nonDerivative · entry 2

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 320,000

F4 · price: Reflects the average price of shares purchased March 16, 2020. Each line in Table I of the original Form 4, filed March 17, 2020, correctly aggregated purchases within a $1.00 price range.

F2 · balance_after: Amended to reflect total direct ownership of Issuer shares as of the original Form 4 filing date. Purchases reported on and after March 16, 2020 were erroneously added to existing indirect holdings. These indirect holdings of 46,005,227 (which correspond to a post stock-split total of 92,010,554 shares) are owned by TTWF LP and further described by footnote 12 below.

F3 · ownership.direct: Erroneously reported as indirect holdings. Amended to reflect direct ownership.

SEC source: 0001567619-20-006376 · doc1.xml · nonDerivative · entry 2

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 46,165,277

F2 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $33.18 to $34.00, 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.

F3 · ownership.nature: 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.

SEC source: 0001567619-20-006376 · doc1.xml · nonDerivative · entry 1

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 46,119,014

F1 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions ranging from $23.17 to $33.17, 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 purchased at each separate price within the ranges set forth in this footnote.

F3 · ownership.nature: 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.

SEC source: 0001567619-20-015789 · doc1.xml · nonDerivative · entry 1

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 160,000

F1 · price: Reflects the average price of shares purchased March 13, 2020. Each line in Table I of the original Form 4, filed March 16, 2020, correctly aggregated purchases within a $1.00 price range.

F2 · balance_after: Amended to reflect total direct ownership of Issuer shares as of the original Form 4 filing date. Purchases reported on and after March 16, 2020 were erroneously added to existing indirect holdings. These indirect holdings of 46,005,227 (which correspond to a post stock-split total of 92,010,554 shares) are owned by TTWF LP and further described by footnote 12 below.

F3 · ownership.direct: Erroneously reported as indirect holdings. Amended to reflect direct ownership.

SEC source: 0001567619-19-007880 · doc1.xml · nonDerivative · entry 1

TTWFGP LLC · CIK 0001299599 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 1,401,869

SEC source: 0000899243-17-021289 · doc4.xml · derivative · entry 2

WPT LLC · CIK 0001262852 · 10% owner

WESTLAKE CHEMICAL CORP · CIK 0001262823 · 10% owner

WESTLAKE POLYMERS LLC · CIK 0001262845 · 10% owner

WESTLAKE CHEMICAL INVESTMENTS, INC. · CIK 0001262834 · 10% owner

WESTLAKE OLEFINS CORP · CIK 0001262842 · 10% owner

TTWF LP · CIK 0001299601 · 10% owner

TTWFGP LLC · CIK 0001299599 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Units (Limited Partner Interests) · 12,686,115 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: On August 30, 2017, pursuant to the terms of the agreement of limited partnership (the "Partnership Agreement") of the Issuer, the 12,686,115 subordinated units representing limited partner interests in the Issuer (the "subordinated units") acquired by WPT LLC ("WPT") in the Issuer's initial public offering converted into common units representing limited partner interests of the Issuer ("common units") on a one-for-one basis, resulting in the acquisition of 12,686,115 common units. The subordinated units had no expiration date.

F1 · price: On August 30, 2017, pursuant to the terms of the agreement of limited partnership (the "Partnership Agreement") of the Issuer, the 12,686,115 subordinated units representing limited partner interests in the Issuer (the "subordinated units") acquired by WPT LLC ("WPT") in the Issuer's initial public offering converted into common units representing limited partner interests of the Issuer ("common units") on a one-for-one basis, resulting in the acquisition of 12,686,115 common units. The subordinated units had no expiration date.

F1 · derivative.exercise_date: On August 30, 2017, pursuant to the terms of the agreement of limited partnership (the "Partnership Agreement") of the Issuer, the 12,686,115 subordinated units representing limited partner interests in the Issuer (the "subordinated units") acquired by WPT LLC ("WPT") in the Issuer's initial public offering converted into common units representing limited partner interests of the Issuer ("common units") on a one-for-one basis, resulting in the acquisition of 12,686,115 common units. The subordinated units had no expiration date.

F1 · derivative.expiration_date: On August 30, 2017, pursuant to the terms of the agreement of limited partnership (the "Partnership Agreement") of the Issuer, the 12,686,115 subordinated units representing limited partner interests in the Issuer (the "subordinated units") acquired by WPT LLC ("WPT") in the Issuer's initial public offering converted into common units representing limited partner interests of the Issuer ("common units") on a one-for-one basis, resulting in the acquisition of 12,686,115 common units. The subordinated units had no expiration date.

F2 · ownership.direct: As of August 30, 2017, (i) WPT owns 55.7% of the outstanding limited partner interests in the Issuer. Westlake Chemical Corporation ("Westlake") owns 100% of Westlake Olefins Corporation, which owns 100% of Westlake Chemical Investments, Inc., which owns 100% of Westlake Polymers LLC, which owns 100% of WPT. TTWF LP, a Delaware limited partnership, holds 92,010,554 shares of Westlake's common stock. TTWF GP LLC, a Delaware limited liability company, is the general partner of TTWF LP. Each of the reporting persons in the above described ownership chain of WPT may be deemed to indirectly own the common units and the subordinated units directly held by WPT.

SEC source: 0000899243-17-021289 · doc4.xml · nonDerivative · entry 1

WPT LLC · CIK 0001262852 · 10% owner

WESTLAKE CHEMICAL CORP · CIK 0001262823 · 10% owner

WESTLAKE POLYMERS LLC · CIK 0001262845 · 10% owner

WESTLAKE CHEMICAL INVESTMENTS, INC. · CIK 0001262834 · 10% owner

WESTLAKE OLEFINS CORP · CIK 0001262842 · 10% owner

TTWF LP · CIK 0001299601 · 10% owner

TTWFGP LLC · CIK 0001299599 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 14,122,230

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: On August 30, 2017, pursuant to the terms of the agreement of limited partnership (the "Partnership Agreement") of the Issuer, the 12,686,115 subordinated units representing limited partner interests in the Issuer (the "subordinated units") acquired by WPT LLC ("WPT") in the Issuer's initial public offering converted into common units representing limited partner interests of the Issuer ("common units") on a one-for-one basis, resulting in the acquisition of 12,686,115 common units. The subordinated units had no expiration date.

F1 · balance_after: On August 30, 2017, pursuant to the terms of the agreement of limited partnership (the "Partnership Agreement") of the Issuer, the 12,686,115 subordinated units representing limited partner interests in the Issuer (the "subordinated units") acquired by WPT LLC ("WPT") in the Issuer's initial public offering converted into common units representing limited partner interests of the Issuer ("common units") on a one-for-one basis, resulting in the acquisition of 12,686,115 common units. The subordinated units had no expiration date.

F2 · ownership.direct: As of August 30, 2017, (i) WPT owns 55.7% of the outstanding limited partner interests in the Issuer. Westlake Chemical Corporation ("Westlake") owns 100% of Westlake Olefins Corporation, which owns 100% of Westlake Chemical Investments, Inc., which owns 100% of Westlake Polymers LLC, which owns 100% of WPT. TTWF LP, a Delaware limited partnership, holds 92,010,554 shares of Westlake's common stock. TTWF GP LLC, a Delaware limited liability company, is the general partner of TTWF LP. Each of the reporting persons in the above described ownership chain of WPT may be deemed to indirectly own the common units and the subordinated units directly held by WPT.