Document:

EX-4.2

 Exhibit 4.2 

Execution Version 
  

 
  

WESTLAKE CHEMICAL CORPORATION 

1.625% Senior Notes due 2029 
  

 
 Twelfth
Supplemental Indenture 
 Dated as of July 17, 2019 

 
  

THE BANK OF NEW YORK MELLON TRUST COMPANY, N.A. 

Trustee 
  

 
  

 TABLE OF CONTENTS 
  

							
	 	  	Page	 
		
	ARTICLE ONE Scope of Supplemental Indenture; General	  	 	2	 
		
	ARTICLE TWO Certain Definitions	  	 	2	 
		
	ARTICLE THREE Redemption	  	 	9	 
			
	 Section 3.12.
	 	 Optional Redemption
	  	 	9	 
	 Section 3.13.
	 	 Redemption for Tax Reasons
	  	 	10	 
		
	ARTICLE FOUR Covenants	  	 	10	 
			
	 Section 4.08.
	 	 Restrictions on Secured Debt
	  	 	10	 
	 Section 4.09.
	 	 Limitations on Sale and Leaseback Transactions
	  	 	12	 
	 Section 4.10.
	 	 Change of Control Triggering Event
	  	 	13	 
	 Section 4.11.
	 	 Additional Amounts
	  	 	15	 
		
	ARTICLE FIVE [Reserved]	  	 	16	 
		
	ARTICLE SIX Miscellaneous	  	 	17	 
			
	 Section 6.01.
	 	 No Recourse Against Others
	  	 	17	 
	 Section 6.02.
	 	 Governing Law
	  	 	17	 
	 Section 6.03.
	 	 No Adverse Interpretation of Other Agreements
	  	 	17	 
	 Section 6.04.
	 	 Successors and Assigns
	  	 	17	 
	 Section 6.05.
	 	 Duplicate Originals
	  	 	17	 
	 Section 6.06.
	 	 Severability
	  	 	17	 
	 Section 6.07.
	 	 Amendments to the Base Indenture Applicable to the Notes Only
	  	 	18	 
	 Section 6.08.
	 	 Rights of Trustee
	  	 	19	 
	 Section 6.09.
	 	 Waiver of Jury Trial
	  	 	19	 
	 Section 6.10.
	 	 Force Majeure
	  	 	19	 
	 Section 6.11.
	 	 No Recitals, etc.
	  	 	19	 
	 Section 6.12.
	 	 Notices
	  	 	19	 
	 Section 6.13.
	 	 Issuance in Euro
	  	 	20	 
	 Section 6.14.
	 	 Foreign Account Tax Compliance Act
	  	 	20	 
		
	EXHIBIT A Form of Note	  	 	A-1	 

  
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 TWELFTH SUPPLEMENTAL INDENTURE dated as of July 17, 2019 (this “Supplemental
Indenture”), to the Indenture dated as of January 1, 2006 (the “Indenture”), by and among WESTLAKE CHEMICAL CORPORATION, a Delaware corporation (the “Company”), each of the potential guarantors named
therein and THE BANK OF NEW YORK MELLON TRUST COMPANY, N.A. (as successor to JPMorgan Chase Bank, National Association), as trustee (the “Trustee”). 

Each party agrees as follows for the benefit of the other parties and for the equal and ratable benefit of the Holders (as defined herein):

 WHEREAS, the Company and the Trustee have duly authorized the execution and delivery of the Indenture to provide for the issuance from
time to time of the Company’s debentures, notes, bonds or other evidences of indebtedness to be issued in one or more series as in the Indenture provided (as defined therein, “Securities”); 

WHEREAS, the Company desires and has requested the Trustee to join it in the execution and delivery of this Supplemental Indenture in order to
establish and provide for the issuance by the Company of a series of Securities designated as its 1.625% Senior Notes due 2029, substantially in the form attached hereto as Exhibit A (the “Notes”), on the
terms set forth herein; 
 WHEREAS, Section 2.01 of the Indenture provides that a supplemental indenture may be entered into by the
Company and the Trustee for such purpose provided certain conditions are met; 
 WHEREAS, the conditions set forth in the Indenture for the
execution and delivery of this Supplemental Indenture have been complied with; and 
 WHEREAS, all things necessary to make this
Supplemental Indenture a valid agreement of the Company and the Trustee, in accordance with its terms, and a valid amendment of, and supplement to, the Indenture have been done; 

 NOW, THEREFORE: 

In consideration of the premises and the purchase and acceptance of the Notes by the Holders thereof, the Company covenants and agrees with the
Trustee, for the equal and ratable benefit of the Holders, that the Indenture is supplemented and amended, to the extent expressed herein, as follows: 

ARTICLE ONE 
 Scope of
Supplemental Indenture; General 
 The changes, modifications and supplements to the Indenture effected by this Supplemental Indenture
shall be applicable only with respect to, and govern the terms of, the Notes, which shall not be limited in aggregate principal amount, and shall not apply to any other Securities that may be issued under the Indenture unless a supplemental
indenture with respect to such other Securities specifically incorporates such changes, modifications and supplements. Pursuant to this Supplemental Indenture, there is hereby created and designated a series of Securities under the Indenture
entitled “1.625% Senior Notes due 2029.” The Notes shall be in the form of Exhibit A hereto, which is hereby incorporated into this Supplemental Indenture by reference. 

ARTICLE TWO 
 Certain
Definitions 
 The following terms have the meanings set forth below in this Supplemental Indenture. Capitalized terms used but not
defined herein have the meanings ascribed to such terms in the Indenture. To the extent terms defined herein differ from the Indenture the terms defined herein will govern. 

“ACTUAL/ACTUAL (ICMA)” means the interest payment convention by which interest on the Notes is computed on the basis of the actual
number of days in the period for which interest is being calculated and the actual number of days from and including the last date on which interest was paid on the Notes (or from July 17, 2019, if no interest has been paid on the Notes), to
but excluding the next scheduled Interest Payment Date. 
 “Attributable Debt” means, as to any lease in respect of a Sale
and Leaseback Transaction under which any Person is at the time liable, at any date as of which the amount thereof is to be determined, the total net amount of rent required to be paid by such Person under such lease during the remaining term
thereof (or, if earlier, the first date upon which such lease may be terminated without penalty), discounted from the respective due dates thereof to such date at the rate per annum borne by the Notes, compounded annually. The net amount of rent
required to be paid under any such lease for any such period shall be the aggregate amount of the rent payable by the lessee with respect to such period after excluding amounts required to be paid on account of maintenance and repairs, insurance,
taxes, assessments, water rates and similar charges. Unless the Company elects to calculate the total 

  
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amount of rent required to be paid through the first date upon which such lease may be terminated without penalty (if such a provision exists), in the case of any lease which is terminable by the
lessee upon the payment of a penalty, such net amount shall also include the amount of such penalty, but no rent shall be considered as required to be paid under such lease subsequent to the first date upon which it may be so terminated. 

“Below Investment Grade Rating Event” means the rating on the Notes is lowered and as a result the Notes cease to be rated
Investment Grade by each of the Rating Agencies on any date during the period (the “Trigger Period”) commencing on the earlier of (a) the occurrence of a Change of Control and (b) the first public announcement by the
Company of any Change of Control (or pending Change of Control) and ending 60 days following the consummation of such Change of Control (which Trigger Period will be extended if the rating of the Notes is under publicly announced consideration for
possible downgrade by any Rating Agency on such 60th day, such extension to last with respect to each Rating Agency until the date on which such Rating Agency considering such possible downgrade either (x) rates the Notes below Investment Grade
or (y) publicly announces that it is no longer considering the Notes for possible downgrade; provided, that no such extension will occur if on such 60th day the Notes are rated Investment Grade not subject to review for possible downgrade by
any Rating Agency); provided, that a rating event will not be deemed to have occurred in respect of a particular Change of Control (and thus will not be deemed a Below Investment Grade Rating Event for purposes of the definition of Change of Control
Triggering Event contained in this Article Two) if each Rating Agency making the reduction in rating does not publicly announce or confirm or inform the Trustee in writing at the Company’s request that the reduction was the result, in whole or
in part, of any event or circumstance comprised of or arising as a result of, or in respect of, the Change of Control (whether or not the applicable Change of Control has occurred at the time of the Below Investment Grade Rating Event). If any
Rating Agency withdraws its rating on the Notes or otherwise ceases to provide a rating on the Notes on any day during the Trigger Period for any reason and the Company has not selected a replacement Rating Agency pursuant to the terms of this
Supplemental Indenture, the rating of such Rating Agency shall be deemed to be rated below Investment Grade on such day. 

“Beneficial Owner” has the meaning assigned to such term in Rule 13d-3 and Rule 13d-5 under the Exchange Act, except that in calculating the beneficial ownership of any particular “person” as such term is used in Section 13(d)(3) of the Exchange Act, such “person” will
be deemed to have beneficial ownership of all securities that such “person” has the right to acquire by conversion or exercise of other securities, whether such right is currently exercisable or is exercisable only upon the occurrence of a
subsequent condition. 
 “Business Day” is any day that is: (a) not a Saturday, a Sunday or a day on which banking
institutions in any of New York, New York, Houston, Texas or London, United Kingdom are authorized or obligated by law, regulation or executive order to remain 

  
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closed; and (b) a day on which commercial banking institutions are open for business and carrying out transactions in Euros in the United Kingdom and in the country in which the Paying Agent
has its specified office and is a day on which the Trans-European Automated Real Time Gross Settlement Express Transfer System is operating. 

“Capital Stock” means: 

(1)    in the case of a corporation, capital stock; 

(2)    in the case of an association or business entity, any and all shares, interests, participations,
rights or other equivalents (however designated) of capital stock; 
 (3)    in the case of a partnership
or limited liability company, partnership interests (whether general or limited) or membership interests, respectively; and 

(4)    any other interest or participation that confers on a Person the right to receive a share of the
profits and losses of, or distributions of assets of, the issuing Person, but excluding from all of the foregoing any debt securities convertible into Capital Stock, whether or not such debt securities include any right of participation with Capital
Stock. 
 “Change of Control” means the occurrence of any of the following after the date of this Supplemental Indenture:

 (1)    the direct or indirect sale, lease, transfer, conveyance or other disposition (other than by way of merger or
consolidation), in one or a series of related transactions, of all or substantially all of the assets of the Company and the Subsidiaries taken as a whole to any “person” or “group” (as those terms are used in
Section 13(d)(3) of the Exchange Act) other than to the Company or a Subsidiary; 
 (2)    the consummation of any
transaction (including, without limitation, any merger or consolidation) the result of which is that any “person” or “group” (as those terms are used in Section 13(d)(3) of the Exchange Act, it being agreed that an employee
of the Company or any Subsidiary for whom shares are held under an employee stock ownership, employee retirement, employee savings or similar plan and whose shares are voted in accordance with the instructions of such employee shall not be a member
of a “group” (as that term is used in Section 13(d)(3) of the Exchange Act) solely because such employee’s shares are held by a trustee under said plan) becomes the ultimate Beneficial Owner, directly or indirectly, of Voting
Stock of the Company representing more than 50% of the voting power of the outstanding Voting Stock of the Company; 

  
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 (3)    the Company consolidates with, or merges with or into, any
Person, or any Person consolidates with, or merges with or into, the Company, in any such event pursuant to a transaction in which any of the outstanding Voting Stock of the Company or Voting Stock of such other Person is converted into or exchanged
for cash, securities or other property, other than any such transaction where the Voting Stock of the Company outstanding immediately prior to such transaction constitutes, or is converted into or exchanged for, Voting Stock representing more than
50% of the voting power of the Voting Stock of the surviving Person or its parent immediately after giving effect to such transaction; 

(4)    during any period of 24 consecutive calendar months, the majority of the members of the Board of Directors of the
Company shall no longer be composed of individuals (a) who were members of the Board of Directors of the Company on the first day of such period or (b) whose election or nomination to the Board of Directors of the Company was approved by
individuals referred to in clause (a) above constituting, at the time of such election or nomination, at least a majority of the Board of Directors of the Company or, if directors are nominated by a committee of the Board of Directors of the
Company, constituting at the time of such nomination, at least a majority of such committee; or 
 (5)    the adoption
of a plan relating to the liquidation or dissolution of the Company. 
 Notwithstanding the foregoing, a transaction will not be deemed to
involve a Change of Control if (i) the Company becomes a direct or indirect wholly-owned subsidiary of a holding company and (ii) the direct or indirect holders of the Voting Stock of such holding company immediately following that
transaction are substantially the same as the holders of the Voting Stock in the Company immediately prior to that transaction. 

“Change of Control Offer” has the meaning provided in Section 4.10(a). 

“Change of Control Payment” has the meaning provided in Section 4.10(a). 

“Change of Control Payment Date” has the meaning provided in Section 4.10(b). 

“Change of Control Triggering Event” means the occurrence of both a Change of Control and a Below Investment Grade Rating
Event. Notwithstanding the foregoing, no Change of Control Triggering Event will be deemed to have occurred in connection with any particular Change of Control unless and until such Change of Control has actually been consummated. 

“Clearing System” each of Euroclear Bank SA/NV and Clearstream Banking S.A. in Luxembourg. 

“Clearing System Business Day” means a day on which each Clearing System for which any global security is being held is open
for business. 

  
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 “Company” has the meaning provided in the Indenture. 

“Comparable Government Bond” means, in relation to any Comparable Government Bond Rate calculation, at the discretion of an
independent investment bank selected by the Company, a German government bond whose maturity is closest to the maturity of the Notes to be redeemed, or if such independent investment bank in its discretion determines that such similar bond is not in
issue, such other German government bond as such independent investment bank may, with the advice of three brokers of, and/or market makers in, German government bonds selected by the Company, determine to be appropriate for determining the
Comparable Government Bond Rate. 
 “Comparable Government Bond Rate” means, with respect to any Redemption Date, the
price, expressed as a percentage (rounded to three decimal places, with 0.0005 being rounded upwards), at which the gross redemption yield on the Notes to be redeemed, if they were to be purchased at such price on the third Business Day prior to the
date fixed for redemption, would be equal to the gross redemption yield on such Business Day of the Comparable Government Bond (as defined above) on the basis of the middle market price of the Comparable Government Bond prevailing at 11:00 a.m.
(London time) on such Business Day as determined by an independent investment bank selected by the Company. 
 “Consolidated Net
Tangible Assets” means the aggregate amount of assets (less applicable reserves and other properly deductible items) after deducting therefrom (1) all current liabilities, except for (a) notes and loans payable, (b) current
maturities of long-term debt and (c) current maturities of obligations under finance leases and (2) all goodwill, trade names, trademarks, patents, unamortized debt discount and expense and other like intangibles, all as set forth on the
most recent balance sheet of the Company and its consolidated Subsidiaries and computed in accordance with GAAP. Deferred income taxes, deferred investment tax credit or other similar items, as calculated in accordance with GAAP, will not be
considered as a liability or as a deduction from or adjustment to total assets. 
 “Debt” has the meaning provided in
Section 4.08. 
 “Domestic Subsidiary” means any Subsidiary that was formed under the laws of the United States or any
state of the United States or the District of Columbia. 
 “Euro” and “€” means the official currency
of the European Union member states participating in the European Monetary Union; “Fair Market Value” means the price that could be negotiated in an arm’s-length transaction between a
willing buyer and a willing seller not involving distress or necessity of either party, determined in good faith by the Board of Directors of the Company. 

  
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 “Funded Debt” means all indebtedness for money borrowed having a maturity
of more than 12 months from the date of the most recent balance sheet of the Company and its consolidated Subsidiaries or having a maturity of less than 12 months but by its terms being renewable or extendible beyond 12 months from the date of such
balance sheet at the option of the borrower of such indebtedness. 
 “Holder” means the Person in whose name a Note is
registered in the books of the Registrar for the Notes. 
 “Indenture” has the meaning provided in the Preamble. 

“Investment Grade” means a rating of Baa3 or better by Moody’s (or its equivalent under any successor rating category of
Moody’s) and a rating of BBB- or better by S&P (or its equivalent under any successor rating category of S&P), and the equivalent investment grade credit rating from any replacement rating agency
or rating agencies selected by the Company under the circumstances specified in this Supplemental Indenture permitting the Company to select a replacement rating agency and in the manner specified in this Supplemental Indenture for selecting a
replacement rating agency, in each case as set forth in the definition of “Rating Agency.” 
 “Moody’s”
means Moody’s Investors Service, Inc., a subsidiary of Moody’s Corporation, and its successors. 
 “Mortgage” and
“Mortgages” have the meanings provided in Section 4.08. 
 “Notes” has the meaning provided in the
Recitals. 
 “Par Call Date” has the meaning provided in Section 3.12. 

“Paying Agent” means The Bank of New York Mellon, London Branch or any successor paying agent. 

“Person” means any individual, corporation, limited liability company, partnership, joint venture, incorporated or
unincorporated association, joint stock company, trust, estate, unincorporated organization or government or any agency, instrumentality or political subdivision thereof or any other entity of any kind. 

“Principal Property” means any single parcel of real estate, any single manufacturing plant or any single warehouse owned or
leased in connection with a Sale and Leaseback Transaction by the Company or any Subsidiary which is located within the United States and the net book value of which on the date as of which the determination is being made exceeds 1% of Consolidated
Net Tangible Assets, other than any such manufacturing plant or warehouse or portion thereof (1) which is a pollution control or other facility financed 

  
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by obligations issued by a state or local government unit and described in Sections 141(a), 142(a)(5), 142(a)(6), 142(a)(10) or 144(a) of the Internal Revenue Code (or their successor provisions)
or by any other obligations the interest of which is excluded under Section 103 of the Internal Revenue Code (or its successor provision), or (2) which, in the good-faith opinion of the Board of Directors of the Company, as evidenced by a
Board Resolution, is not of material importance to the total business conducted by the Company and the Subsidiaries taken as a whole. 

“Rating Agency” means each of Moody’s and S&P; provided, that if any of Moody’s or S&P ceases to provide
rating services to issuers or investors, the Company may appoint another “nationally recognized statistical rating organization” (as defined under the Exchange Act) as a replacement for such Rating Agency; provided, that the Company shall
give written notice of such appointment to the Trustee. 
 “Registrar” means The Bank of New York Mellon Trust Company,
N.A., or any successor registrar of the Notes. 
 “Restricted Subsidiary” means a wholly-owned Subsidiary of the Company
substantially all of the assets of which are located in the United States (excluding territories or possessions) and which owns a Principal Property; provided, however, that the term Restricted Subsidiary shall not include any Subsidiary that is
principally engaged in (1) the business of financing; (2) the business of owning, buying, selling, leasing, dealing in or developing real property; or (3) the business of exporting goods or merchandise from or importing goods or
merchandise into the United States. 
 “S&P” means S&P Global Ratings, a division of S&P Global, Inc., and its
successors. 
 “Sale and Leaseback Transaction” has the meaning provided in Section 4.09. 

“Secured Debt” has the meaning provided in Section 4.08. 

“Subsidiary” means a Person more than 50% of the outstanding Voting Stock of which is owned, directly or indirectly, by the
Company or by one or more other Subsidiaries, or by the Company and one or more other Subsidiaries. 
 “Supplemental
Indenture” has the meaning provided in the Preamble. 
 “Trustee” has the meaning provided in the Preamble. 

  
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 “Voting Stock” of any specified Person as of any date means the capital
stock (or comparable equity interests) of such Person that is at the time entitled to vote generally in the election of the board of directors (or members of the governing body) of such Person. 

ARTICLE THREE 
 Redemption

 The following provision shall be added to Article III of the Indenture, but only with respect to the Notes: 

Section 3.12.    Optional Redemption. 

(a)    The Company may redeem the Notes, at its option, in whole or in part, at any time and from time to
time prior to April 17, 2029 (three months prior to the Maturity Date of the Notes, the “Par Call Date”) in principal amounts of €1,000 and integral multiples of €1,000 in excess thereof, provided that the unredeemed portion
of a Note must be in a minimum principal amount of €100,000, for a Redemption Price equal to the greater of: 

(i)    100% of the principal amount of the Notes to be redeemed; and 

(ii)    the sum of the present values of the remaining scheduled payments on the Notes being redeemed that
would be due if the Notes matured on the Par Call Date (not including any portion of such payments of interest accrued as of the Redemption Date), discounted to the Redemption Date on an annual basis (ACTUAL/ACTUAL (ICMA)) at a rate equal to the
applicable Comparable Government Bond Rate plus 30 basis points, 
 plus accrued and unpaid interest on the Notes being redeemed to the
Redemption Date. 
 (b)    The Company may redeem the Notes, at its option, in whole or in part, at any time and from
time to time on or after the Par Call Date, in principal amounts of €1,000 and integral multiples of €1,000 in excess thereof, provided that the unredeemed portion of a Note must be in a minimum principal amount of €100,000, at a
Redemption Price equal to 100% of the principal amount of the Notes being redeemed plus accrued and unpaid interest on the Notes being redeemed to the Redemption Date. 

  
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 (c)    The Company may at any time, and from time to time, purchase the
Notes at any price or prices in the open market, through negotiated transactions, by tender offer or otherwise. 

(d)    The Company shall have no obligation to make mandatory redemption of the Notes or to redeem, purchase or repay
Notes pursuant to any sinking fund or analogous provision or, except as provided in Section 4.10, at the option of a Holder thereof. 

(e)    With respect to any redemption occurring prior to the Par Call Date, the Company shall deliver notice to the Trustee
of the related Redemption Price not less than 10 days nor more than 60 days before the Redemption Date and the Trustee shall not have any responsibility for such calculation. 

Section 3.13.    Redemption for Tax Reasons. 

If, as a result of any change in, or amendment to, the laws (or any regulations or rulings promulgated under the laws) of the United States (or
any taxing authority in the United States), or any change in, or amendment to, an official position regarding the application or interpretation of such laws, regulations or rulings, which change or amendment is announced and becomes effective on or
after the issue date of the Notes, the Company determines (based on an opinion issued to the Company by counsel of recognized standing with respect to U.S. federal income tax matters) that the Company becomes obligated to pay additional amounts as
described in Section 4.11 with respect to the Notes, then the Company may at any time at its option redeem, in whole, but not in part, the Notes on not less than 30 nor more than 60 days’ prior notice, at a redemption price equal to 100%
of their principal amount, together with accrued and unpaid interest on the Notes to, but not including, the Redemption Date. 
 ARTICLE FOUR

 Covenants 
 The
following covenants are added to Article IV of the Indenture for the benefit of Holders, but only with respect to the Notes: 

Section 4.08.    Restrictions on Secured Debt. 

The Company shall not, and the Company shall not permit any Restricted Subsidiary to, incur, issue, assume or guarantee any notes, bonds,
debentures or other similar evidences of indebtedness for money borrowed (“Debt”), secured by pledge of, or mortgage or lien on, any Principal Property, or any shares of Capital Stock of or Debt of any Restricted

  
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Subsidiary (such pledges, mortgages and liens being called “Mortgage” or “Mortgages” and such Debt secured by such Mortgages being called “Secured
Debt”), without effectively providing that the Notes (together with, if the Company shall so determine, any other indebtedness of the Company or such Restricted Subsidiary then existing or thereafter created which is not subordinate to the
Notes) shall be secured equally and ratably with (or prior to) such Secured Debt, so long as such Secured Debt shall be so secured, unless after giving effect thereto, the aggregate amount of all such Secured Debt plus all Attributable Debt of the
Company and its Restricted Subsidiaries in respect of any Sale and Leaseback Transaction would not, at the time of such incurrence, issuance, assumption or guarantee, exceed 15% of Consolidated Net Tangible Assets; provided, however, that this
restriction shall not apply to, and there shall be excluded from Secured Debt in any computation under such restriction, indebtedness secured by: 

(a)    Mortgages on such property or shares of Capital Stock or Debt existing on the date of this
Supplemental Indenture; 
 (b)    Mortgages on such property or shares of Capital Stock of or Debt of any
Person, which Mortgages are existing at the time (i) such Person became a Restricted Subsidiary, (ii) such Person is merged into or consolidated with the Company or any Subsidiary or (iii) the Company or a Subsidiary merges into or
consolidates with such Person (in a transaction in which such Person becomes a Restricted Subsidiary), which Mortgage was not incurred in anticipation of such transaction and was outstanding prior to such transaction; 

(c)    Mortgages in favor of the Company; 

(d)    Mortgages in favor of a governmental entity or in favor of the holders of securities issued by any
such entity, pursuant to any contract or statute (including Mortgages to secure debt of the pollution control or industrial revenue bond type) or to secure any indebtedness incurred for the purpose of financing all or any part of the purchase price
or the cost of construction of the property subject to such Mortgages; 
 (e)    Mortgages in favor of
any governmental entity to secure progress, advance or other payments pursuant to any contract or provision of any statute; 

(f)    Mortgages on such property or shares of Capital Stock or Debt existing at the time of acquisition
thereof (including acquisition through merger or consolidation); 
 (g)    Mortgages on such property or
shares of Capital Stock or Debt to secure the payment of all or any part of the purchase price or construction cost thereof or to secure any Debt incurred prior to, at the time of, or within 180 days after, the acquisition

  
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of such property or shares or Debt, the completion of any construction or the commencement of full operation, for the purpose of financing all or any part of the purchase price or construction
cost thereof; 
 (h)    Mortgages incurred in connection with a Sale and Leaseback Transaction satisfying
the provisions set forth in Section 4.09; and 
 (i)    any extension, renewal or replacement (or
successive extensions, renewals or replacements), as a whole or in part, of any Mortgage referred to in the foregoing clauses; provided that such extension, renewal or replacement Mortgage shall be limited to all or a part of the same such property
or shares of Capital Stock or Debt that secured the Mortgage extended, renewed or replaced (plus improvements on such property). 

Section 4.09.    Limitations on Sale and Leaseback Transactions. 

The Company shall not, and shall not permit any Restricted Subsidiary to, enter into any arrangement with any bank, insurance company or other
lender or investor (not including the Company or any Restricted Subsidiary) or to which any such lender or investor is a party, providing for the leasing by the Company or a Restricted Subsidiary for a period, including renewals, in excess of three
years of any Principal Property the ownership of which has been or is to be sold or transferred, more than 180 days after the completion of construction and commencement of full operation thereof, by the Company or such Restricted Subsidiary to such
lender or investor or to any Person to whom funds have been or are to be advanced by such lender or investor on the security of such Principal Property (referred to as a “Sale and Leaseback Transaction”) unless: 

(a)    such Sale and Leaseback Transaction is with a governmental entity that provides financial or tax
benefits; 
 (b)    the Company or such Restricted Subsidiary could create Secured Debt pursuant to the
provisions set forth in Section 4.08 on the Principal Property to be leased in an amount equal to the Attributable Debt with respect to such Sale and Leaseback Transaction without equally and ratably securing the Notes; or 

(c)    the net proceeds of the sale or transfer of the Principal Property leased pursuant to such Sale and
Leaseback Transaction is at least equal to the Fair Market Value of such Principal Property and within 180 days after such sale or transfer shall have been made by the Company or by a Restricted Subsidiary, the Company shall apply an amount not less
than the greater of (i) the net proceeds of the sale of the Principal Property leased pursuant to such arrangement or (ii) the Fair Market Value of the Principal Property so leased at the time of entering into such arrangement (as
evidenced 

  
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by an Officers’ Certificate delivered to the Trustee) to the retirement of Funded Debt of the Company; provided that the amount to be applied to the retirement of Funded Debt of the Company
shall be reduced by (x) the principal amount of Notes delivered within 180 days after such sale to the Trustee for retirement and cancellation, and (y) the principal amount of Funded Debt other than Notes, voluntarily retired by the
Company within 180 days after such sale. No retirement referred to in this clause (c) may be effected by payment at maturity or pursuant to any mandatory sinking fund payment or mandatory prepayment provision. 

Section 4.10.    Change of Control Triggering Event. 

(a)    Upon the occurrence of a Change of Control Triggering Event, unless the Company, subject to
Section 4.10(d), has exercised its right to redeem the Notes in accordance with Section 3.12, each Holder will have the right to require the Company to purchase all or a portion (€1,000 or an integral multiple of €1,000 in excess
thereof) of such Holder’s Notes pursuant to the offer described below (the “Change of Control Offer”), at a purchase price equal to 101% of the principal amount thereof plus accrued and unpaid interest, if any, to the date of
purchase (the “Change of Control Payment”), subject to the rights of Holders on the relevant record date to receive interest due on the relevant Interest Payment Date; provided that the principal amount of a Note remaining
outstanding after a repurchase in part shall be €100,000 or an integral multiple of €1,000 in excess thereof. 

(b)    Within 30 days following the date upon which the Change of Control Triggering Event occurred, or at
the Company’s option, prior to any Change of Control but after the public announcement of the pending Change of Control, the Company shall deliver a notice to each Holder of Notes that were not redeemed, with a copy to the Trustee, which notice
shall govern the terms of the Change of Control Offer. Such notice will, among other things, state the purchase date, which must be no earlier than 30 days nor later than 60 days from the date such notice is sent, other than as may be required by
applicable law (the “Change of Control Payment Date”), describe the transaction or transactions constituting the Change of Control Triggering Event and offer to repurchase the Notes. The notice, if sent prior to the date of
consummation of the Change of Control, shall state that the Change of Control Offer is conditioned on the Change of Control being consummated on or prior to the Change of Control Payment Date. 

(c)    On the Change of Control Payment Date, the Company shall, to the extent lawful: 

(i)    accept or cause a third party to accept for payment all Notes or portions of Notes properly tendered
pursuant to the Change of Control Offer; 

  
 -13- 

 (ii)    deposit or cause a third party to deposit with
the Paying Agent an amount equal to the Change of Control Payment in respect of all Notes or portions of Notes properly tendered; and 

(iii)    deliver or cause to be delivered to the Trustee the Notes to be redeemed properly accepted
together with an Officers’ Certificate stating the aggregate principal amount of Notes or portions of Notes being repurchased and that all conditions precedent to the Change of Control Offer and to the repurchase by the Company of Notes
pursuant to the Change of Control Offer have been complied with. 
 (d)    The Company will not be
required to make a Change of Control Offer with respect to the Notes if (i) a third party makes such an offer in the manner, at the times and otherwise in compliance with the requirements for such an offer otherwise required to be made by the
Company and such third party purchases all such Notes properly tendered and not withdrawn under its offer or (ii) a notice of redemption has been given to the Holders of all of the Notes in accordance with the terms of the Indenture, unless and
until there is a default in payment of the Redemption Price. 
 (e)    A Change of Control Offer may be
made in advance of a Change of Control, conditional upon such Change of Control, if a definitive agreement is in place with respect to the Change of Control at the time of making of the Change of Control Offer. 

(f)    The Company will comply in all material respects with the requirements of Rule 14e-1 under the Exchange Act, and any other securities laws and regulations thereunder to the extent those laws and regulations are applicable in connection with the repurchase of the Notes as a result of a Change
of Control Triggering Event. To the extent that the provisions of any such securities laws or regulations conflict with this Section 4.10, the Company will comply with those securities laws and regulations and will not be deemed to have
breached its obligations under this Section 4.10 by virtue of any such conflict. 

  
 -14- 

 Section 4.11. Additional Amounts 

The Company will, subject to the exceptions and limitations set forth below, pay as additional interest on the Notes such additional amounts as
are necessary in order that the net payment of the principal of and interest on the Notes to a Holder that is not a United States person (as defined below), after withholding or deduction for any present or future tax, assessment or other
governmental charge imposed by the United States or a taxing authority in the United States, will not be less than the amount provided in the Notes to be then due and payable; provided, however, that the foregoing obligation to pay additional
amounts shall not apply: 
 (a)    to any tax, assessment or other governmental charge that is imposed
solely by reason of the Holder (or the beneficial owner for whose benefit such Holder holds such Note), or a fiduciary, settlor, beneficiary, member or shareholder of the Holder if the Holder is an estate, trust, partnership or corporation, or a
person holding a power over an estate or trust administered by a fiduciary Holder, being considered as: 

(i)    being or having been engaged in a trade or business in the United States or having or having had a
permanent establishment in the United States; 
 (ii)    having a current or former connection with the
United States (other than a connection arising solely as a result of the ownership of the Notes or the receipt of any payment or the enforcement of any rights thereunder), including being or having been a citizen or resident of the United States;

 (iii)    being or having been a personal holding company, a passive foreign investment company or a
controlled foreign corporation for United States federal income tax purposes or a corporation that has accumulated earnings to avoid United States federal income tax; 

(iv)    being or having been a “10-percent shareholder”
of the Company as defined in section 871(h)(3) of the United States Internal Revenue Code of 1986, as amended (the “Code”), or any successor provision; or 

(v)    being a bank receiving payments on an extension of credit made pursuant to a loan agreement entered
into in the ordinary course of its trade or business; 
 (b)    to any Holder that is not the sole
beneficial owner of the Notes, or a portion of the Notes, or that is a fiduciary, partnership or limited liability company, but only to the extent that a beneficial owner with respect to the Holder, a beneficiary or settlor with respect to the
fiduciary, or a beneficial owner or member of the partnership or limited liability company would not have been entitled to the payment of an additional amount had the beneficiary, settlor, beneficial owner or member received directly its beneficial
or distributive share of the payment; 
 (c)    to any tax, assessment or other governmental charge that
would not have been imposed but for the failure of the Holder or any other person to comply with certification, identification or information reporting requirements concerning the nationality, residence, identity or connection with the United States
of the Holder or beneficial owner of the Notes, if compliance is required by statute, by regulation of the United States or any taxing authority therein or as a precondition to exemption from such tax, assessment or other governmental charge; 

  
 -15- 

 (d)    to any tax, assessment or other governmental
charge that is imposed otherwise than by withholding by the Company or an applicable withholding agent from the payment; 

(e)    to any estate, inheritance, gift, sales, transfer, wealth, capital gains or personal property tax or
similar tax, assessment or other governmental charge; 
 (f)    to any tax, assessment or other
governmental charge that would not have been imposed but for the presentation by the Holder of any Note, where presentation is required, for payment on a date more than 30 days after the date on which payment became due and payable or the date on
which payment thereof is duly provided for, whichever occurs later; 
 (g)    to any tax, assessment or
other governmental charge imposed under Sections 1471 through 1474 of the Code (or any amended or successor provisions), any current or future regulations or official interpretations thereof, any agreement entered into pursuant to
Section 1471(b) of the Code or any fiscal or regulatory legislation, rules or practices adopted pursuant to any intergovernmental agreement entered into in connection with the implementation of such sections of the Code; or 

(h)    in the case of any combination of items (a), (b), (c), (d), (e), (f) and (g). 

The Notes are subject in all cases to any tax, fiscal or other law or regulation or administrative or judicial interpretation applicable to the Notes. Except
as specifically provided in this Section 4.11, the Company will not be required to make any payment for any tax, assessment or other governmental charge imposed by any government or a political subdivision or taxing authority of or in any
government or political subdivision. 
 As used in this Section 4.11 and in Section 3.13, the term “United States” means the United
States of America, the states of the United States, and the District of Columbia, and the term “United States person” means any individual who is a citizen or resident of the United States for United States federal income tax purposes, a
corporation, partnership or other entity created or organized in or under the laws of the United States, any state of the United States or the District of Columbia, or any estate or trust the income of which is subject to United States federal
income taxation regardless of its source. 
 ARTICLE FIVE 

[Reserved] 

  
 -16- 

 ARTICLE SIX 

Miscellaneous 

Section 6.01.    No Recourse Against Others. 

Section 11.08 of the Indenture shall be amended by replacing that section of the Indenture with the following, but only with respect to
the Notes: 
 A director, officer, member, manager, employee, stockholder, partner or other owner of the Company, or the Trustee, as such,
shall not have any liability for any obligations of the Company under the Notes or for any obligations of the Company or the Trustee under this Indenture or for any claim based on, in respect of or by reason of such obligations or their creation.
Each Holder by accepting a Note waives and releases all such liability. The waiver and release shall be part of the consideration for the issuance of Notes. 

Section 6.02.    Governing Law. 

The laws of the State of New York shall govern this Supplemental Indenture and the Notes. 

Section 6.03.    No Adverse Interpretation of Other Agreements. 

This Supplemental Indenture may not be used to interpret another indenture (other than the Indenture), loan or debt agreement of the Company.
Any such indenture, loan or debt agreement may not be used to interpret this Supplemental Indenture. 

Section 6.04.    Successors and Assigns. 

All covenants and agreements of the Company in this Supplemental Indenture and the Notes shall bind its successors and assigns. All agreements
of the Trustee in this Supplemental Indenture shall bind its successors and assigns. 
 Section 6.05.    Duplicate
Originals. 
 The parties may sign any number of copies of this Supplemental Indenture. Each signed copy shall be an original, but all of
them together represent the same agreement. 
 Section 6.06.    Severability. 

In case any provision in this Supplemental Indenture or in the Notes shall be invalid, illegal or unenforceable, the validity, legality and
enforceability of the remaining provisions shall, to the fullest extent permitted by applicable law, not in any way be affected or impaired thereby. 

  
 -17- 

 Section 6.07.    Amendments to the Base Indenture Applicable to the Notes
Only. 
 (a)    With respect to the Notes only, the definition of “Government Obligations” in
Section 1.01 of the Base Indenture is amended and restated in its entirety, and shall read as follows: 
 “Government Obligations” means,
with respect to a series of Securities, (i) direct obligations of a government that issues the currency in which the Securities of the series are payable for the payment of which the full faith and credit of such government is pledged, or, in
the case of a series of Securities denominated in Euros, direct obligations of a government of a country in the European Monetary Union for the payment of which the full faith and credit of such government is pledged, (ii) obligations of a
Person controlled or supervised by and acting as an agency or instrumentality of such government, the payment of which is unconditionally guaranteed as a full faith and credit obligation by such government, which, in either case under clause
(i) or (ii) above, are not callable or redeemable at the option of the issuer thereof; or (iii) depository receipts issued by a bank or trust company as custodian with respect to any such Government Obligations or a specific payment of
interest on or principal of any such Government Obligation held by such custodian for the account of the holder of a depository receipt, provided that (except as required by law) such custodian is not authorized to make any deduction from the amount
payable to the holder of such depository receipt from any amount received by the custodian in respect of the Government Obligation evidenced by such depository receipt. 

(b)    With respect to the Notes only, Section 11.07 of the Indenture is amended and restated in its entirety, and
shall read as follows: 
 SECTION 11.07 Business Days. 

If the principal of or any premium or interest on the Notes is payable on a day that is not a Business Day, the payment will be made on the
following Business Day and no interest shall accrue for the intervening period. 
 (c) Section 9.01 of the Indenture is supplemented
with the addition of the following with respect to the Notes: 
 (12)    to provide any other
modifications which do not adversely affect the interests of the Holders in any material respect. 

(13)    to conform the provisions of the Indenture or the Notes to the “Description of the Senior
Notes” section of the final prospectus supplement relating to the Notes, dated July 10, 2019. 

  
 -18- 

 Section 6.08.    Rights of Trustee. 

In no event shall the Trustee be responsible or liable for special, indirect, or consequential loss or damage of any kind whatsoever
(including, but not limited to, loss of profit) irrespective of whether the Trustee has been advised of the likelihood of such loss or damage and regardless of the form of action. 

The Trustee may request that the Company deliver an Officers’ Certificate setting forth the names of individuals and/or titles of
officers (with specimen signatures) authorized at such times to take specific actions pursuant to this Supplemental Indenture, which Officers’ Certificate may be signed by any person specified as so authorized in any such certificate previously
delivered and not superseded. 
 Section 6.09.    Waiver of Jury Trial. 

The Company and the Trustee hereby irrevocably waives, to the fullest extent permitted by applicable law, any and all right to trial by jury in
any legal proceeding arising out of or relating to this Supplemental Indenture, the Indenture, the Notes or the transactions contemplated hereby. 

Section 6.10.    Force Majeure. 

In no event shall the Trustee be responsible or liable for any failure or delay in the performance of its obligations under this Supplemental
Indenture arising out of or caused by, directly or indirectly, forces beyond its reasonable control, including, without limitation, strikes, work stoppages, accidents, acts of war or terrorism, civil or military disturbances, nuclear or natural
catastrophes or acts of God, and interruptions, loss or malfunctions of utilities, communications or computer (software or hardware) services. 

Section 6.11.    No Recitals, etc. 

The Trustee shall not be responsible in any manner whatsoever for or in respect of the validity or sufficiency of this Supplemental Indenture
or for or in respect of the recitals contained herein, all of which are made solely by the Company. 

Section 6.12.    Notices. 

The Trustee agrees to accept and act upon instructions or directions pursuant to this Indenture sent by unsecured e-mail, pdf, facsimile transmission or other similar unsecured electronic methods, provided, however, that the Trustee shall have received an incumbency certificate listing persons designated to give such
instructions or directions and containing specimen signatures of such designated persons, which such incumbency certificate shall be amended and replaced as necessary prior to the giving of such instructions or directions. If

  
 -19- 

 
the Company elects to give the Trustee e-mail or facsimile instructions (or instructions by a similar electronic method) and the Trustee in its discretion
elects to act upon such instructions, the Trustee’s understanding of such instructions shall be deemed controlling. The Trustee shall not be liable for any losses, costs or expenses arising directly or indirectly from the Trustee’s
reliance upon and compliance with such instructions notwithstanding such instructions conflict or are inconsistent with a subsequent written instruction. The Company agrees to assume all risks arising out of the use of such electronic methods to
submit instructions and directions to the Trustee, including without limitation the risk of the Trustee acting on unauthorized instructions, and the risk or interception and misuse by third parties. 

Section 6.13.    Issuance in Euro 

All payments of interest and principal, including payments made upon any redemption of the Notes, will be payable in Euros. If the Euro is
unavailable to the Company due to the imposition of exchange controls or other circumstances beyond the Company’s control or if the Euro is no longer being used by the then member states of the European Monetary Union that have adopted the Euro
as their currency or for the settlement of transactions by public institutions of or within the international banking community, then all payments in respect of the Notes will be made in Dollars until the Euro is again available to the Company or so
used. The amount payable on any date in Euros will be converted into dollars on the basis of the most recently available market exchange rate for Euros. Any payment in respect of the Notes so made in dollars will not constitute an Event of Default.
Neither the Trustee nor the Paying Agent shall have any responsibility for any calculation or conversion in connection with the foregoing. 

Section 6.14.    Foreign Account Tax Compliance Act. 

Each of the Company and the Trustee agrees to provide the other with such information in its possession (subject in all cases to applicable
privacy laws) as reasonably requested by the other to enable the determination of whether any payment to a Holder pursuant to the Indenture is subject to withholding imposed pursuant to Sections 1471 through 1474 of the Internal Revenue Code, any
regulations thereunder, intergovernmental agreements in respect thereof or official interpretations of any of the foregoing (“Applicable FATCA Law”). 

  
 -20- 

 SIGNATURES 

IN WITNESS WHEREOF, the parties have caused this Supplemental Indenture to be duly executed, all as of the date first above written. 

 

			
	WESTLAKE CHEMICAL CORPORATION

 
			
		
	By:	 	 /S/ ALBERT CHAO

	Name:	 	Albert Chao
	Title:	 	President and Chief Executive Officer

  
 [Signature Page to
Twelfth Supplemental Indenture] 

			
	 The Bank of New York Mellon Trust Company, N.A.,
as Trustee

		
	By:	 	 /S/ KAREN YU

	Name:	 	Karen Yu
	Title:	 	Vice President

  
 [Signature Page to
Twelfth Supplemental Indenture] 

 EXHIBIT A 

FORM 
 OF 

1.625% SENIOR NOTE DUE 2029 
  

 
 A-1 

  

 [FORM OF FACE OF NOTE] 

Global Notes Legend 
 THIS NOTE
IS A GLOBAL SECURITY WITHIN THE MEANING OF THE INDENTURE HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF THE COMMON DEPOSITARY (OR ITS NOMINEE) FOR, AND DEPOSITED WITH, CLEARSTREAM BANKING S.A. IN LUXEMBOURG (“CLEARSTREAM”) AND/OR
EUROCLEAR BANK SA/NV (“EUROCLEAR” AND, TOGETHER WITH EUROCLEAR, “EUROCLEAR/CLEARSTREAM”) (THE “COMMON DEPOSITARY”). UNLESS AND UNTIL IT IS EXCHANGED IN WHOLE OR IN PART FOR NOTES IN CERTIFICATED FORM, THIS NOTE MAY NOT
BE TRANSFERRED EXCEPT AS A WHOLE BY THE COMMON DEPOSITARY OR OTHER DULY APPOINTED DEPOSITARY TO A NOMINEE OF THE DEPOSITARY OR BY A NOMINEE OF THE DEPOSITARY TO THE DEPOSITARY OR ANOTHER NOMINEE OF THE DEPOSITARY OR BY THE DEPOSITARY OR ANY SUCH
NOMINEE TO A SUCCESSOR DEPOSITARY OR A NOMINEE OF SUCH SUCCESSOR DEPOSITARY. 
 UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED
REPRESENTATIVE OF EUROCLEAR/CLEARSTREAM, TO THE ISSUER HEREOF OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF THE BANK OF NEW YORK DEPOSITORY (NOMINEES) LIMITED OR TO SUCH
OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF EUROCLEAR/CLEARSTREAM, ANY TRANSFER, PLEDGE, OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, THE BANK OF NEW YORK
DEPOSITORY (NOMINEES) LIMITED, HAS AN INTEREST HEREIN. 
 NO. [    ]
            CUSIP / ISIN / Common Code NO. 960413 AV4 / XS2028104037 / 202810403 

WESTLAKE CHEMICAL CORPORATION 

1.625% SENIOR NOTE DUE 2029 
  

			
	Principal Amount:	  	€700,000,000
		
	Regular Record Date:	  	the close of business (in the relevant Clearing System) on the Clearing System Business Day immediately preceding each Interest Payment Date (or, if the Notes are held in definitive form, the 15th calendar day preceding each
Interest Payment Date, whether or not a Business Day).
		
	Original Issue Date:	  	July 17, 2019
		
	Stated Maturity:	  	July 17, 2029

  
 A-2 

			
	Interest Payment Dates:	  	July 17, commencing July 17, 2020
		
	Interest Rate:	  	1.625% per annum
		
	Authorized Denomination:	  	€100,000 and integral multiples of €1,000 in excess thereof

 WESTLAKE CHEMICAL CORPORATION, a corporation duly organized and existing under the laws of the State of
Delaware (herein called the “Company,” which term includes any successor under the Indenture referred to below), for value received, hereby promises to pay to
                                    , or its registered assigns, the
principal sum of
                                        
(€                            ) on the Stated Maturity shown above (or upon any earlier date of
redemption or acceleration of maturity) (each such date being hereinafter referred to as the “Maturity Date”) and to pay interest thereon, from and including the immediately preceding Interest Payment Date to which interest has been
paid or duly provided for (or from, and including, the Original Issue Date if no interest has been paid or duly provided for), to, but excluding, the Maturity Date, annually in arrears on each Interest Payment Date as specified above, commencing on
July 17, 2020 at the rate per annum shown above until the principal hereof is paid or made available for payment and at such rate on any overdue principal and on any overdue installment of interest. Capitalized terms used herein shall have the
meanings specified in the Indenture. 
 Reference is hereby made to the further provisions of this Note set forth on the reverse hereof,
which provisions shall for all purposes have the same force and effect as if set forth on the face hereof. 
 Unless the Certificate of
Authentication hereon has been executed by the Trustee by manual signature, this Note shall not be entitled to any benefit under the Indenture or be valid or obligatory for any purpose. 

  
 A-3 

 IN WITNESS WHEREOF, the Company has caused this instrument to be duly executed. 

 

			
	WESTLAKE CHEMICAL CORPORATION

 
			
		
	By:	 	     

	Name:	 	
	Title:	 	
		
	By:	 	     

	Name:	 	
	Title:	 	

 CERTIFICATE OF AUTHENTICATION 

This is one of the Securities of the series designated therein referred to in the within-mentioned Indenture. 

Date of Authentication:                     ,
20     
 THE BANK OF NEW YORK MELLON TRUST COMPANY, N.A., 

Trustee 
  

			
	By:	 	  

		 	Authorized Signatory

  
 A-4 

 [REVERSE OF NOTE] 

Westlake Chemical Corporation 

1.625% Senior Note due 2029 
 This Note is
one of a duly authorized issue of 1.625% Senior Notes due 2029 (the “Notes”) of Westlake Chemical Corporation, a Delaware corporation (the “Company”). Capitalized terms used herein shall have the meanings specified in the
Indenture (as defined below). 
 1.    Interest. 

The Company promises to pay interest on the principal amount of this Note at the rate per annum shown above. The Company shall pay such
interest annually in arrears on July 17 of each year, commencing July 17, 2020. Interest will be paid on the close of business (in the relevant Clearing System) on the Clearing System Business Day immediately preceding each Interest
Payment Date (or, if the Notes are held in definitive form, the 15th calendar day preceding each Interest Payment Date, whether or not a Business Day) (each such date, a “Regular Record Date”), even if such Interest Payment Date is a
Redemption Date, Change of Control Payment Date or other Maturity Date, except as provided in Section 2.14 of the Indenture with respect to defaulted interest. Interest on the Notes will accrue from the most recent date to which interest has
been paid or duly provided for or, if no interest has been paid or duly provided for, from July 17, 2020. Interest will be computed on the basis of the actual number of days in the period for which interest is being calculated and the actual
number of days from and including the last date on which interest was paid on the notes (or from July 17, 2019, if no interest has been paid on the notes), to but excluding the next scheduled Interest Payment Date (ACTUAL/ACTUAL (ICMA)). 

2.    Method of Payment. 

Upon the terms and subject to the conditions of the Indenture, the Company will make all payments of the Redemption Price and Change of Control
Payment and principal due at Maturity in respect of the Notes to Holders who surrender such Notes to a Paying Agent to collect such payments; provided that if any Redemption Date, Change of Control Payment Date or other Maturity Date is an
Interest Payment Date, accrued and unpaid interest shall be paid to the Holder as of the immediately preceding Regular Record Date. The Company will pay all amounts due in respect of the Notes in money of the European Monetary Union that at the time
of payment is legal tender for payment of public and private debts. At the option of the Company, the Company may elect for such amounts to be paid (i) by wire transfer of immediately available funds in Euros so long as the Notes are
represented by Global Securities, or (ii) by check payable in such money mailed to a Holder’s registered address with respect to any certificated Notes. 

3.    Paying Agent and Registrar. 

Initially, The Bank of New York Mellon Trust Company, N.A., the Trustee under the Indenture, will act as Registrar at its office at 601 Travis
Street, 16th Floor, Houston, Texas 77002, and The Bank of New York Mellon, London Branch will act as the initial Paying Agent at its office at One Canada Square, London E14 5AL, United Kingdom pursuant to a Paying Agency Agreement entered into by
the Company and the Paying Agent on July 17, 2019. The Company may appoint and change any Paying Agent or Registrar without notice to any Holder. The Company or any of its other Subsidiaries may act as Paying Agent or Registrar. 

  
 A-5 

 4.    Indenture. 

The Company issued the Notes under an Indenture dated as of January 1, 2006 (the “Base Indenture”), as supplemented by the
Twelfth Supplemental Indenture dated as of July 17, 2019 (the “Twelfth Supplemental Indenture,” and together with the Base Indenture, the “Indenture”) between the Company and the Trustee. The terms of the Notes include those
stated in the Indenture and those made part of the Indenture by reference to the Trust Indenture Act of 1939, as amended (the “TIA”). The Notes are subject to all such terms, and Holders are referred to the Indenture and the TIA for a
statement of such terms. To the extent any provision of this Note conflicts with the express provisions of the Indenture, the provisions of the Indenture shall govern and be controlling. The Notes are general unsecured obligations of the Company and
are initially issued in an aggregate principal amount of €700,000,000. The Company may, subject to the provisions of the Indenture, issue additional Notes of the same series as the Notes from time to time without the consent of the Holders. The
Notes initially issued and any additional Notes subsequently issued under the Indenture will be treated as a single series for all purposes of the Indenture, including, without limitation, with respect to waivers, amendments, supplements,
redemptions and offers to purchase. The Indenture provides for the issuance of other series of debt securities (including the Notes, the “Securities”) thereunder. 

5.    Optional Redemption. 

The Company may redeem the Notes, at its option, in whole or in part, at any time and from time to time prior to April 17, 2029 (three
months prior to the Maturity Date of the Notes, the “Par Call Date”) in principal amounts of €1,000 and integral multiples of €1,000 in excess thereof, provided that the unredeemed portion of a Note must be in a minimum principal
amount of €100,000, for a Redemption Price equal to the greater of: 
  

	 	(a)	 100% of the principal amount of the Notes to be redeemed; and 

 

	 	(b)	 the sum of the present values of the remaining scheduled payments on the Notes being redeemed that would be due
if the Notes matured on the Par Call Date (not including any portion of such payments of interest accrued as of the Redemption Date), discounted to the Redemption Date on an annual basis (ACTUAL/ACTUAL (ICMA)) at a rate equal to the applicable
Comparable Government Bond Rate plus 30 basis points, 

  
 A-6 

 plus accrued and unpaid interest on the Notes being redeemed to the Redemption Date. 

(c)    The Company may redeem the Notes, at its option, in whole or in part, at any time and from time to time on or after
the Par Call Date, in principal amounts of €1,000 and integral multiples of €1,000 in excess thereof, provided that the unredeemed portion of a Note must be in a minimum principal amount of €100,000, at a Redemption Price equal to
100% of the principal amount of the Notes being redeemed plus accrued and unpaid interest on the Notes being redeemed to the Redemption Date. 

6.    Mandatory Redemption and Redemption for Tax Reasons. 

(a)    The Company will not be required to make mandatory redemption or sinking fund payments with respect to the Notes;

 (b)     If, as a result of any change in, or amendment to, the laws (or any regulations or rulings promulgated under
the laws) of the United States (or any taxing authority in the United States), or any change in, or amendment to, an official position regarding the application or interpretation of such laws, regulations or rulings, which change or amendment is
announced and becomes effective on or after the issue date of the Notes, the Company determines (based on an opinion issued to the Company by counsel of recognized standing with respect to U.S. federal income tax matters) that the Company becomes
obligated to pay additional amounts as described in Section 4.11 with respect to the Notes, then the Company may at any time at its option redeem, in whole, but not in part, the Notes on not less than 30 nor more than 60 days’ prior
notice, at a redemption price equal to 100% of their principal amount, together with accrued and unpaid interest on the Notes to, but not including, the Redemption Date. 

7.    Notice of Redemption. 

The Company shall deliver notice of a redemption not less than 10 days nor more than 60 days before the Redemption Date to Holders of Notes to
be redeemed. Once notice of redemption is sent, the Notes called for redemption will become due and payable on the Redemption Date at the applicable Redemption Price. A notice of redemption may not be conditional. 

8.    Repurchase at the Option of Holder. 
  

	 	(a)	 Upon the occurrence of a Change of Control Triggering Event, unless the Company has exercised its right to
optionally redeem the Notes, each Holder will have the right to require the Company to purchase all or a portion (€1,000 or an integral multiple of €1,000 in excess thereof) of such Holder’s Notes pursuant to the Change of Control
Offer, at a purchase price equal to 101% of the principal amount thereof plus accrued and unpaid interest, if any, to the Change of Control Payment Date, subject to the rights of Holders on the relevant record date to receive interest due on the
relevant Interest Payment Date; provided that the principal amount of a Note remaining outstanding after a repurchase in part shall be €100,000 or an integral multiple of €1,000 in excess thereof. 

 

	 	(b)	 Within 30 days following the date upon which the Change of Control Triggering Event occurred, or at the
Company’s option, prior to any Change of Control but after the public announcement of the pending Change of Control, the Company will be required to send, 

  
 A-7 

	 	
by first class mail, a notice to each Holder of the Notes, with a copy to the Trustee, which notice will govern the terms of the Change of Control Offer. Such notice will, among other things,
state the Change of Control Payment Date, which must be no earlier than 30 days nor later than 60 days from the date such notice is mailed, other than as may be required by applicable law, describe the transaction or transactions constituting the
Change of Control Triggering Event and offer to repurchase the Notes. 

 9.    Denominations; Transfer; Exchange.

 The Notes initially are issued in permanent global form. Under certain circumstances described in the Indenture, Notes may also be issued
in the form of certificated Notes in fully registered form, without coupons, in minimum denominations of €100,000 and integral multiples of €1,000 in excess thereof. The Registrar may require a Holder, among other things, to furnish
appropriate endorsements and transfer documents and to pay any transfer taxes or similar governmental changes required by law or permitted by the Indenture. The Registrar need not register the transfer or exchange of any Notes selected for
redemption in whole or in part (except the unredeemed portion of any Note to be redeemed in part) or any Notes during a period beginning 15 Business Days prior to the delivery of the relevant notice of redemption or repurchase and ending on the
close of business on the day of delivery such notice. 
 10.    Persons Deemed Owners. 

The registered Holder of a Note may be treated as its owner for all purposes. 

11.    Amendment; Waiver. 

Subject to certain exceptions and limitations, the Indenture or the Securities may be amended or supplemented with the consent of the Holders
of at least a majority in principal amount of the then outstanding Securities of all series affected by such amendment or supplement (acting as one class), and any existing or past Default or Event of Default under, or compliance with any provision
of, the Indenture may be waived (other than any continuing Default or Event of Default in the payment of the principal of, premium (if any) on or interest on the Securities) by the Holders of at least a majority in principal amount of the then
outstanding Securities of any series or of all series (acting as one class) in accordance with the terms of the Indenture. Subject to certain exceptions set forth in the Indenture, without the consent of any Holder, the Company, and the Trustee may
amend or supplement the Indenture or the Securities in certain respects set forth in the Indenture. 
 Without the consent of each Holder
affected, the Company may not (i) reduce the amount of Securities whose Holders must consent to an amendment, supplement or waiver; (ii) reduce the rate of or change the time for payment of interest, including default interest, on any
Security; (iii) reduce the principal of or premium on, or change the Stated Maturity of, any Security; (iv) reduce the premium, if any, payable upon the redemption of any Security or change the time at which any Security may or shall be
redeemed; (v) change any obligation of the Company to pay Additional Amounts with respect to any Security; (vi) change the coin or currency in which any Security or any premium or interest with respect thereto is payable; (vii) impair
the right to institute suit for the enforcement of any payment of principal of or premium (if any) or interest on any Security, except as provided in the Indenture; (viii) make any change in the percentage of principal amount of Securities
necessary to waive compliance with certain provisions of the Indenture or make any change in the provision for modification; or (ix) waive a continuing Default or Event of Default in the payment of principal of or premium (if any) or interest
on the Securities. 

  
 A-8 

 A supplemental indenture that changes or eliminates any covenant or other provision of the
Indenture which has expressly been included solely for the benefit of one or more particular series of Securities under the Indenture, or which modifies the rights of the Holders of Securities of such series with respect to such covenant or other
provision, shall be deemed not to affect the rights under the Indenture of the Holders of Securities of any other series. 

12.    Defaults and Remedies. 

Under the Indenture, Events of Default include (i) default in the payment of interest that continues for a period of 30 days;
(ii) default in any payment of principal of or premium, if any, on the Notes when due and payable; (iii) failure by the Company to comply with any of its other covenants or agreements in the Indenture or the Notes, which shall not have
been remedied within the specified time period after written notice; and (iv) certain events of bankruptcy or insolvency with respect to the Company. If an Event of Default occurs and is continuing, either the Trustee or the Holders of at least
25% in aggregate principal amount of the Notes at the time outstanding (or, in the case of an Event of Default described in clause (iii) above, if outstanding Securities of other series are affected by such Default, then at least 25% in
principal amount of the then outstanding Securities so affected), may declare the principal amount of all the Securities (or the Notes) to be due and payable immediately, together with accrued and unpaid interest thereon. Certain events of
bankruptcy or insolvency are Events of Default that will result in the principal amount of the Notes, together with accrued and unpaid interest thereon, becoming due and payable immediately upon the occurrence of such Events of Default. 

As set forth in, and subject to the provisions of, the Indenture, no Holder of any Securities shall have any right to institute any
proceeding, judicial or otherwise, with respect to the Indenture, or for the appointment of a receiver or trustee, or for any other remedy thereunder, unless certain conditions set forth in the Indenture have been satisfied. The Trustee may refuse
to enforce the Indenture or the Securities unless it receives indemnity satisfactory to it. Subject to certain limitations (including that, in some cases, a majority in principal amount of all outstanding Securities (or the Notes) is required),
Holders of a majority in aggregate principal amount of the outstanding Securities (or the Notes) have the right to direct the time, method and place of conducting certain proceedings, or exercising any trust or power conferred on the Trustee. 

13.    Trustee Dealings with the Company. 

Subject to certain limitations imposed by the TIA, the Trustee under the Indenture, in its individual or any other capacity, may become the
owner or pledgee of Notes and may otherwise deal with the Company with the same rights it would have if it were not Trustee. 

14.    Discharge Prior to Maturity. 

The Indenture with respect to the Notes shall be discharged and canceled upon the payment of all of the Notes and shall be discharged except
for certain obligations upon the irrevocable deposit with the Trustee of any combination of funds and Government Obligations sufficient for such payment as provided in the Indenture. 

  
 A-9 

 15.    No Recourse Against Others. 

A director, officer, member, manager, employee, stockholder, partner or other owner of the Company, or the Trustee, as such, shall not have any
liability for any obligations of the Company under the Notes, or for any obligations of the Company or the Trustee under the Indenture or for any claim based on, in respect of or by reason of such obligations or their creation. Each Holder by
accepting a Note waives and releases all such liability. The waiver and release shall be part of the consideration for the issuance of Notes. 

16.    CUSIP, ISIN and Common Code Numbers. 

Pursuant to a recommendation promulgated by the Committee on Uniform Security Identification Procedures, the Company has caused CUSIP, ISIN and
Common Code numbers to be printed on the Notes and the Trustee may use CUSIP, ISIN and Common Code numbers in notices of redemption as a convenience to Holders. No representation is made as to the accuracy of such numbers either as printed on the
Notes or as contained in any notice of redemption and reliance may be placed only on the other identification numbers placed thereon. 

17.    Abbreviations. 

Customary abbreviations may be used in the name of a Holder or an assignee, such as: TEN COM (= tenants in common), TEN ENT (= tenants by the
entireties), JT TEN (= joint tenants with right of survivorship and not as tenants in common), CUST (= Custodian), and U/G/M/A (= Uniform Gifts to Minors Act). 

  
 A-10 

 ASSIGNMENT FORM 

To assign this Note, fill in the form below: 
 I or we assign
and transfer this Note to 
  
  

 
 (Print or type assignee’s name,
address and zip code) 
  
  

 
 (Insert assignee’s soc. sec. or
tax I.D. No.) 
 and irrevocably appoint
                                         
                                         
                                         
                                         
                                     agent to transfer this Note
on the books of the Company. The agent may substitute another to act for him. 
  
  

 
  

											
	Date:	  	  
	 	        	 	Your Signature:	  	  
	  	
		  		 		 		  	Sign exactly as your name appears on the other side of this note	  	

  

	
	  
 Your Signature

  

					
	Signature Guarantee:	  	  
 Signature must be guaranteed by a
participant in a recognized signature guaranty medallion program or other signature guarantor acceptable to the Trustee
	  	

  
 A-11 

Date:                       
                                         

  
  

 
 Signature
of Signature Guarantee 

  
 A-12EX-4.4

 Exhibit 4.4 

EXECUTION VERSION 
 Dated:
July 17, 2019 
 Westlake Chemical Corporation 

as Issuer 
 and 

The Bank of New York Mellon, London Branch 

as Paying Agent 
 PAYING AGENCY
AGREEMENT 

 THIS AGREEMENT is made as of July 17, 2019 between Westlake Chemical
Corporation (the “Issuer”), and The Bank of New York Mellon, London Branch as paying agent (the “Paying Agent”), located at One Canada Square, London E14 5AL. 

WHEREAS, the Issuer proposes to issue (i) Euro denominated 1.625% Senior Notes due 2029 in the form attached hereto as Annex A (the
“Notes”) in the aggregate principal amount of €700 million on the date hereof, pursuant to an indenture, dated as of January 1, 2006 (the “Base Indenture”), among the Issuer, the potential subsidiary
guarantors party thereto and The Bank of New York Mellon Trust Company, N.A. (as successor to JPMorgan Chase Bank, National Association), as trustee (the “Trustee”), as amended and supplemented by that certain Twelfth Supplemental
Indenture (the “Twelfth Supplemental Indenture” and, together with the Base Indenture, the “Indenture”), dated as of July 17, 2019, between the Issuer and the Trustee; 

WHEREAS, solely with respect to the Notes, the Issuer wishes to appoint the Paying Agent, as set forth above, upon the terms and subject to
the conditions set forth herein; 
 NOW, THEREFORE, in consideration of the mutual promises contained herein, the parties hereto agree as
follows: 
  

	1	 Definitions 

  

	1.1	 All capitalized terms used herein, but not defined, shall have the meanings given to them in the
Indenture. 

  

	1.2	 In addition, the following terms shall have the following meanings: 

“Business Day” means any day that is: (a) not a Saturday, a Sunday or a day on which banking institutions in any of New
York, New York, Houston, Texas or London, United Kingdom is authorized or obligated by law, regulation or executive order to remain closed; and (b) a day on which commercial banking institutions are open for business and carrying out
transactions in Euros in the United Kingdom and in the country in which the Paying Agent has its specified office and is a day on which the Trans-European Automated Real Time Gross Settlement Express Transfer System is operating. 

“Holder(s)” means the person(s) in whose name(s) the Note is registered in the Trustee’s register. 

References to the records of Euroclear Bank S.A./N.V. (“Euroclear”) and Clearstream Banking, société anonyme
(“Clearstream”) shall be to the records that each of Euroclear and Clearstream holds for its customers which reflect the amount of such customers’ interests in the Notes. 

  
 1 

	 	2	 Appointment of Paying Agent 

The Issuer hereby appoints The Bank of New York Mellon, London Branch at its office specified above as the paying agent solely in respect of
the Notes upon the terms and conditions herein contained, and The Bank of New York Mellon, London Branch accepts such appointment.  

 

	 	3	 Payment 

  

	3.1	 In order to provide for all payments due on the Notes as the same shall become due, the Issuer shall
cause to be paid to the Paying Agent, no later than 1:00 p.m. London time one Business Day prior to the due date for the payment of each Note, at such bank as the Paying Agent shall previously have notified to the Issuer, in immediately available
funds sufficient to meet all payments due on such Notes. 

  

	3.2	 The Issuer hereby authorizes and directs the Paying Agent, from the amounts paid to it pursuant to this
Section 3, to make or cause to be made all payments on the Notes in accordance with the terms thereof. Such payments shall be made to the Holder or Holders of Notes in accordance with the terms of the Notes, the provisions contained in this
Agreement, and the procedures of Euroclear and Clearstream. All interest payments in respect of the Notes will be made by the Paying Agent on the relevant interest payment date (as set forth in the Note) to the Holders in whose names the Notes are
registered on the record date specified in the Notes next preceding the interest payment date or such other date as is provided in the Notes. At the option of the Issuer, the Issuer may elect for such amounts to be paid (1) by wire transfer of
immediately available funds in Euros (so long as the Notes are represented by a single global certificate) or (2) by check payable in such money mailed to a Holder’s registered address with respect to any Notes. 

 

	3.3	 The Paying Agent will pay the principal amount of each Note and premium, if any, and additional amounts,
if any, on the applicable maturity date or upon any redemption date with respect thereto, together with accrued and unpaid interest due at maturity or such redemption date, if any, upon presentation and surrender of such Note on or after the
maturity date or redemption date thereof to the Paying Agent, or as specified in the Notes. 

  

	3.4	 If for any reason the amounts received by the Paying Agent are insufficient to satisfy all claims in
respect of all payments then due on the Notes, the Paying Agent shall forthwith notify the Issuer, and the Paying Agent shall not be obliged to pay any such claims until the Paying Agent has received the full amount of the monies then due and
payable in respect of such Notes. If, however, the Paying Agent in its sole discretion shall make payment on the Notes on their maturity or redemption, or payments of interest or such other payments when otherwise due (it being understood that the
Paying Agent shall have no obligation whatsoever to make any such payment) and the amount which should have been received is not received on such date, the Issuer agrees forthwith on demand to pay, or procure the payment of, to the Paying Agent, in
addition to the amount which should have been paid hereunder, interest thereon from the day following the date when the amount unpaid should have been received under this Agreement to the date when such amount is actually received (inclusive) at a
rate equal to the cost of the Paying Agent of funding such amount, as certified by the Paying Agent and expressed as a rate per annum. 

  
 2 

	3.5	 The Paying Agent hereby agrees that: 

 

	(i)	 it will hold all sums held by it as Paying Agent for the payment of the principal of, premium, if any,
additional amounts, if any, or interest on the Notes in trust for the benefit of the Holders of the Notes entitled thereto, or for the benefit of the Trustee, as the case may be, until such sums shall be paid out to such Holders or otherwise as
provided in Section 3.6 below and in the Indenture; 

  

	(ii)	 it will promptly give the Trustee notice of: (x) an Issuer deposit for the payment of principal of,
premium, if any, additional amounts, if any, or interest on the Notes, (y) any failure by the Issuer in the making of any deposit for the payment of principal of, premium, if any, additional amounts, if any, or interest on the Notes that shall
have become payable, and (z) any default by the Issuer in making any payment of the principal of, premium, if any, additional amounts, if any, or interest on the Notes where the same shall be due and payable as provided in the Notes;

  

	(iii)	 at any time after an Event of Default in respect of the Notes shall have occurred, the Paying Agent shall, if
so required by notice in writing given by the Trustee to the Paying Agent: (y) thereafter, until otherwise instructed by the Trustee, act as agent of the Trustee under the terms of the Indenture; and/or (z) deliver all Notes and all sums,
documents and records held by the Paying Agent in respect of the Notes to the Trustee or as the Trustee shall direct in such notice; provided that such notice shall be deemed not to apply to any document or record which the Paying Agent is obliged
not to release by any applicable law or regulation; and 

  

	(iv)	 it will comply with section 317(b) of the Trust Indenture Act of 1939, as amended. 

 

	3.6	 Notwithstanding the foregoing: 

 

	(i)	 if any Note is presented or surrendered for payment to the Paying Agent and the Paying Agent has delivered a
replacement therefor or has been notified that the same has been replaced, the Paying Agent shall as soon as is reasonably practicable notify the Issuer in writing of such presentation or surrender and shall not make payment against the same until
it is so instructed by the Issuer and has received the amount to be so paid; and 

  

	(ii)	 the Paying Agent shall cancel each Note against surrender of which it has made full payment and shall deliver
each Note so cancelled by it to the Trustee. 

  

	3.7	 In no event, shall the Paying Agent be obliged to make any payments hereunder if it has not received the
full amount of any payment. 

  

	 	4	 Indemnity 

  

	4.1	 The Issuer shall indemnify the Paying Agent against any losses, liabilities, costs, claims, actions or
demands which it may incur or which may be made against it (but excluding any tax based upon, measured by or determined by reference to the income of the Paying Agent) as a result of or in connection with its appointment or the exercise of its
powers and duties 

  
 3 

	 	
under this Agreement or in respect of the Issuer’s issue of Notes, except to the extent that they have resulted from the Paying Agent’s negligence, willful misconduct or bad faith (as
determined by a court of competent jurisdiction in a final and non-appealable decision). The Paying Agent shall notify the Issuer promptly of any claim for which it may seek indemnity. The failure of the
Paying Agent to so notify the Issuer will relieve the Issuer from any liability which it may have to the Paying Agent for contribution or otherwise under the indemnity contained in this Section, but only to the extent that the Issuer is materially
prejudiced as a direct result of such failure. The Issuer shall defend the claim and the Paying Agent shall cooperate in the defense. The Paying Agent may have separate counsel in any such defense, but the fees and expenses of such counsel shall be
at the expense of the Paying Agent, unless: (i) the employment of such counsel has been specifically authorized in writing by the Issuer; (ii) the Issuer has failed promptly to assume the defense and employ counsel reasonably satisfactory
to the Paying Agent; or (iii) the named parties to any such action (including any impleaded parties) include both the Paying Agent and the Issuer or any affiliate of the Issuer, and such Paying Agent shall have reasonably concluded that either
(x) there may be one or more legal defenses available to it which are different from or additional to those available to the Issuer or such affiliate of the Issuer or (y) a conflict may exist between the Paying Agent and the Issuer or such
affiliate of the Issuer. The Issuer need not pay for any settlement without its consent. 

  

	4.2	 The indemnity contained in this Section shall survive the termination or expiry of this Agreement and
the resignation or removal of the Paying Agent. 

  

	 	5	 General 

  

	5.1	 In acting under this Agreement, the Paying Agent shall not (a) be under any fiduciary duty towards
any person, (b) be responsible for or liable in respect of the authorization, validity or legality of any Note amount paid by it hereunder (except to the extent that any such liability is determined by a court of competent jurisdiction to have
resulted from the Paying Agent’s negligence, willful misconduct or bad faith), (c) be under any obligation towards any person other than the Trustee and Issuer or (d) assume any relationship of agency or trust for or with any Holder.

  

	5.2	 The Paying Agent shall be entitled to treat the registered Holder of any Note as the absolute owner of
such Note for all purposes and make payments thereon accordingly. 

  

	5.3	 The Paying Agent may exercise any of its rights or duties hereunder by or through agents or attorneys,
and shall not be responsible for any misconduct thereof, provided such agent or attorney has been appointed with due care. 

  

	5.4	 The Paying Agent shall not exercise any lien, right of set-off
or similar claim against any Holder of a Note in respect of moneys payable by it under this Agreement; however, should the Paying Agent elect to make a payment pursuant to Section 3.4 hereof, it shall be entitled to appropriate for its own
account out of the funds received by it under Section 3 an amount equal to the amount so paid by it. 

  
 4 

	5.5	 The Paying Agent may (at the reasonable expense of the Issuer) consult on any matter concerning its
duties hereunder any legal adviser or other expert selected by it, and the Paying Agent shall not be liable in respect of anything done, or omitted to be done in good faith in accordance with that adviser’s opinion. At any time, the Paying
Agent may apply to any duly authorized representative of the Issuer for a written instruction, and shall not be liable for an action lawfully taken or omitted to be taken in accordance with such instruction. Notwithstanding anything to the contrary
herein, in no event shall the Paying Agent be entitled to reimbursement of the expenses of such legal adviser or expert with respect to any matter arising from the Paying Agent’s negligence, willful misconduct or bad faith.

  

	5.6	 The Paying Agent shall be entitled to rely, and shall not be liable in respect of anything done or
suffered by it in reliance, on any notice, document, communication or information reasonably believed in good faith by it to be genuine and given by the Issuer, the Issuer’s counsel, the Trustee or the Trustee’s counsel.

  

	5.7	 The Paying Agent shall be obliged to perform only such duties as are specifically set forth herein and
in the Notes, and no implied duties or obligations shall be read into this Agreement or the Notes against the Paying Agent. 

  

	5.8	 The Paying Agent shall not be liable to account to the Issuer for any interest or other amounts in
respect of funds received by it from the Issuer. Money held by the Paying Agent need not be segregated except as required by law. 

  

	5.9	 No provision of this Agreement or the Notes shall require the Paying Agent to risk or expend its own
funds, or to take any action which in its reasonable judgment would result in any expense or liability accruing to it. 

  

	5.10	 In no event will the Paying Agent be responsible or liable for any failure or delay in the performance
of its obligations hereunder arising out of or caused by, directly or indirectly, forces beyond its control, including, without limitation, strikes, work stoppages, acts of war or terrorism, civil or military disturbances, nuclear or natural
catastrophes or acts of God, and interruptions, severe loss or severe malfunctions of utilities, communications or computer (software and hardware) services; it being understood that the Paying Agent will use best reasonable efforts which are
consistent with accepted practices in the banking industry to resume performance as soon as practicable under the circumstances. 

  

	5.11	 The Paying Agent shall have no duty to inquire as to the performance of the covenants of the Issuer, nor
shall it be charged with knowledge of any default or Event of Default under the Indenture. 

  

	5.12	 Notwithstanding any provision of this Agreement to the contrary, the Paying Agent will not in any event
be liable for special, punitive or consequential loss or damage of any kind whatsoever (including but not limited to lost profits), even if the Paying Agent has been advised of the likelihood of such loss or damage and regardless of the form of
action. 

  

	5.13	 The Paying Agent, its officers, directors, employees and shareholders may become the owners of, or
acquire any interest in, the Notes, with the same rights that it or they would have if it were not the Paying Agent, and may engage or be interested in any financial or other transaction with the Issuer as freely as if it were not the Paying Agent.

  
 5 

	5.14	 The Paying Agent shall retain the right not to act and shall not be held liable for refusing to act
unless it has received clear and reasonable documentation which complies with the terms of this Agreement. 

  

	5.15	 The Issuer will supply the Paying Agent with the names and specimen signatures of its authorized persons
as soon as practicable after the date hereof. 

  

	5.16	 Neither the Paying Agent nor its officers, directors, employees, agents or attorneys shall be liable to
the Issuer for any act or omission hereunder, or for any error of judgment made in good faith by it or them, except to the extent such liability has been determined by a court of competent jurisdiction to have resulted from the Paying Agent’s
(or, as applicable, its officers’, directors’, employees’, agents’ or attorneys’) negligence, willful misconduct or bad faith. 

  

	 	6	 Change of Paying Agent 

 

	6.1	 Resignation or Removal of Paying Agent. Any time, other than on a day during the forty-five
(45) day period preceding any payment date for Issuer’s Notes, the Paying Agent may resign by giving at least forty-five (45) days’ prior written notice to Issuer; and the Paying Agent’s agency shall be terminated and its
duties shall cease upon expiration of such forty-five (45) days or such lesser period of time as shall be mutually agreeable to Paying Agent and Issuer. At any time, following at least forty-five (45) days’ prior written notice (or
such lesser period of time as shall be mutually agreeable to the Paying Agent and the Issuer) from the Issuer, the Paying Agent may be removed from its agency. Such removal shall become effective upon the expiration of the forty-five (45) day
or agreed lesser time period (provided that any such removal shall be immediate in case the Paying Agent shall be adjudicated bankrupt or insolvent), and upon payment to the Paying Agent of all amounts payable to it in connection with its agency. In
such event, following payment of its fees and expenses, the Paying Agent shall deliver to the Issuer, or to the Issuer’s designated representative, all Notes (if any) and cash (if any) belonging to the Issuer and, at the Issuer’s
reasonable expense, shall furnish to the Issuer, or to the Issuer’s designated representative, such information regarding the status of the Issuer’s outstanding Notes reasonably requested by the Issuer. 

 

	6.2	 Any corporation into which a Paying Agent may be merged or consolidated or any corporation resulting
from any merger or consolidation to which such Paying Agent is a party or any corporation to which such Paying Agent shall sell or otherwise transfer all or substantially all of its corporate trust or agency assets shall on the date on which such
merger, consolidation or transfer becomes effective, become the successor to such Paying Agent under this Agreement without the execution or filing of any paper or any further act on the part of the parties hereto; provided that such corporation
provides the information required by Section 10.1 of this Agreement. 

  

	 	7	 Compensation, Fees and Expenses 

 

	7.1	 The Issuer will pay to the Paying Agent the compensation, fees and expenses in respect of the Paying
Agent’s services as separately agreed with the Paying Agent. 

  
 6 

	7.2	 The Issuer will also pay all reasonable documented out-of-pocket expenses (including reasonable legal expenses) incurred by the Paying Agent in connection with its services hereunder, together with any applicable value added tax and stamp, issue, or other
documentary taxes and duties, except such as have been determined by a court of competent jurisdiction to have resulted from the Paying Agent’s negligence, willful misconduct or bad faith. 

 

	 	8	 Notices 

  

	8.1	 Each notice or communication under this Agreement shall be made in writing, by fax, email or otherwise
in accordance with this Section 8. Each communication or document to be delivered to any party under this Agreement shall be sent to that party at the fax number, email address or address, and marked for the attention of the person (if any),
from time to time designated by that party to the Paying Agent (or, in the case of the Paying Agent, by it to each other party) for the purpose of this Agreement. The initial telephone number, fax number, email address and person so designated are:

 in the case of the Issuer, at: 

Westlake Chemical Corporation 

2801 Post Oak Boulevard 

Houston, Texas 77056 

Tel no.: + 1 (713) 960-9111 

Fax no.: +1 (713) 629-6239 

Email: bederington@westlake.com 

Attention: General Counsel 

in the case of the Paying Agent, to it at: 

The Bank of New York Mellon, London Branch 

One Canada Square, London E14 5AL 

Attention: Corporate Trust Administration 

Tel no.: +44 (0) 207 964 5028 

Fax no.: +44 (0) 207 964 2536 

With a copy to: 

The Bank of New York Mellon Trust Company, N.A. 

601 Travis Street, 16th Floor 

Houston, TX 77002 

Fax no.: +1 (713) 483-6752 

Email: lisa.mccants@bnymellon.com 

  
 7 

	8.2	 All notices under this Agreement shall be effective (if by fax or email) when good receipt is confirmed
by the recipient following enquiry by the sender and (if in writing) when delivered, except that a communication received outside normal business hours shall be deemed to be received on the next Business Day in the city in which the recipient is
located. 

  

	8.3	 In no event, shall the Paying Agent be liable for any losses arising from the Paying Agent receiving or
transmitting any data from or to an authorized person via any non-secure method of transmission or communication, such as but without limitation, by facsimile or email. The Issuer accepts that some methods of
communication are not secure and the Paying Agent shall not incur any liability for receiving instructions via any such non-secure method. The Paying Agent is authorized to comply with and rely upon any such
notice, instruction or other communications reasonably and in good faith believed by it to have been sent or given by an authorized person. The Issuer shall use all reasonable endeavours to ensure that instructions transmitted to the Paying Agent
pursuant to this Agreement are complete and correct. Any instructions shall be conclusively deemed to be valid instructions from the Issuer to the Paying Agent for the purposes of this Agreement. 

 

	 	9	 Governing Law and Jurisdiction; Waiver of Jury Trial 

 

	9.1	 The interpretation, validity and enforcement of this Agreement, and all legal actions brought under or
in connection with the subject matter of this Agreement, shall be governed by the laws of the State of New York. 

  

	9.2	 Any court action brought under or in connection with the subject matter of this Agreement shall be
brought only in the United States District Court for the Southern District of New York or, if such court would not have jurisdiction over the matter, then only in a New York State court sitting in the Borough of Manhattan, City of New York. Each
Party submits to the exclusive jurisdiction of these courts and agrees not to commence any legal action under or in connection with the subject matter of this Agreement in any other court or forum. 

 

	9.3	 Each Party waives any objection to the laying of the venue of any legal action brought under or in
connection with the subject matter of this Agreement in the Federal or state courts sitting in the Borough of Manhattan, City of New York, and agrees not to plead or claim in such courts that any such action has been brought in an inconvenient
forum. 

  

	9.4	 EACH PARTY HEREBY IRREVOCABLY WAIVES, TO THE FULLEST EXTENT PERMITTED BY APPLICABLE LAW, ANY AND ALL
RIGHT TO TRIAL BY JURY IN ANY LEGAL PROCEEDING ARISING OUT OF OR RELATING TO THIS AGREEMENT OR THE TRANSACTION CONTEMPLATED HEREBY. 

  

	 	10	 U.S. Tax Forms 

 

	10.1	 10.1 The Paying Agent and the Trustee (as applicable, “BNYM”) shall deliver to the Issuer two
properly completed and executed copies of IRS Form W-9 (or appropriate successor form) upon entering into this Agreement (and from time to time thereafter upon reasonable

  
 8 

	 	
request of the Issuer). BNYM agrees that if any form or certification that it previously delivered expires or becomes obsolete or inaccurate in any respect, it shall update such form or
certification promptly or promptly notify the Issuer in writing of its legal inability to do so. Any agent appointed pursuant to Section 5.3 hereof making any payment on the Notes shall deliver to the Issuer two properly completed and
executed copies of IRS Form W-9 (or appropriate successor form) upon such appointment (and from time to time thereafter upon reasonable request of the Issuer). 

 

	10.2	 The terms of this Section 10 shall survive the termination of this Agreement.

  

	 	11	 Withholding 

  

	11.1	 Notwithstanding any other provision of this Agreement, BNYM shall be entitled to make a deduction or
withholding (including the deduction of FATCA Withholding Tax) from any payment which it makes under this Agreement for or on account of any present or future taxes, duties or charges if and to the extent so required by any applicable law and any
current or future regulations or agreements thereunder or official interpretations thereof or any law implementing an intergovernmental approach thereto or by virtue of the relevant Holder failing to satisfy any certification or other requirements
in respect of the Notes (the “Applicable Law”), in which event BNYM shall make such payment after such withholding or deduction has been made and shall account, in a timely manner, to the relevant authorities for the amount so
withheld or deducted, and BNYM shall have no obligation to gross up any payment hereunder or pay any additional amount as a result of having deducted or withheld such tax. The Issuer shall hold harmless BNYM from any loss resulting from BNYM having
deducted or withheld such tax in accordance with Applicable Law. 

  

	11.2	 BNYM agrees to provide the Issuer, and the Issuer agrees to provide BNYM, with such information in its
possession (subject in all cases to applicable privacy laws) as reasonably requested to enable the determination of any tax related obligations under Applicable Law. 

The terms of this section shall survive the termination of this Agreement. 

Definitions: 
 “FATCA
Withholding Tax” shall mean any withholding or deduction pursuant to an agreement described in Section 1471(b) of the Code or otherwise imposed pursuant to Sections 1471 through 1474 of the Code (or any regulations or agreements thereunder
or official interpretations thereof) or any intergovernmental agreement between the United States and another jurisdiction facilitating the implementation thereof (or any law implementing such an intergovernmental agreement). 

“Code” shall mean the US internal Revenue Code of 1986, as amended. 

  
 9 

	 	12	 Counterparts 

This Agreement may be signed in any number of counterparts, each of which shall be deemed an original. 

*    *    *    *    * 

  
 10 

 In witness whereof the parties hereto have caused this Agreement to be duly executed the day
and year first above written. 
  

			
	WESTLAKE CHEMICAL CORPORATION
		
		 	as Issuer                        
		
	By:	 	 /S/ ALBERT CHAO

	Name:	 	Albert Chao
	Title:	 	President and Chief Executive Officer

  
 [Signature to Paying
Agency Agreement] 

			
	Paying Agent
	
	The Bank of New York Mellon, London Branch
		
	By:	 	 /S/ LATOYA S. ELVIN

	Name:	 	Latoya S. Elvin
	Title:	 	Vice President

  
 [Signature to Paying
Agency Agreement] 

 EXHIBIT A 

 
  
  

A-1

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