Document:

Form of Sixth Supplemental Indenture

 Exhibit 4.2 

 
  

 
 WESTLAKE CHEMICAL CORPORATION
AND THE SUBSIDIARY 
 GUARANTORS PARTY HERETO 
 3.600% Senior Notes due 2022 
  

 
 Sixth
Supplemental Indenture 
 Dated as of July 17, 2012 

 
  

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.
	 	Redemption at the Option of the Company.	  	 	9	  
		
	ARTICLE FOUR Covenants	  	 	10	  
			
	 Section 4.08.
	 	Restrictions on Secured Debt.	  	 	10	  
	 Section 4.09.
	 	Limitations on Sale and Leaseback Transactions.	  	 	11	  
	 Section 4.10.
	 	Change of Control Triggering Event.	  	 	12	  
	 Section 4.11.
	 	Additional Guarantees.	  	 	14	  
		
	ARTICLE FIVE Guarantee	  	 	14	  
			
	 Section 5.01.
	 	Release of Subsidiary Guarantors from Guarantee.	  	 	14	  
		
	ARTICLE SIX Miscellaneous	  	 	15	  
			
	 Section 6.01.
	 	No Recourse Against Others.	  	 	15	  
	 Section 6.02.
	 	Governing Law.	  	 	15	  
	 Section 6.03.
	 	No Adverse Interpretation of Other Agreements.	  	 	15	  
	 Section 6.04.
	 	Successors and Assigns.	  	 	16	  
	 Section 6.05.
	 	Duplicate Originals.	  	 	16	  
	 Section 6.06.
	 	Severability.	  	 	16	  
	 Section 6.07.
	 	Amendments Without Consent of Holders.	  	 	16	  
	 Section 6.08.
	 	Rights of Trustee.	  	 	16	  
	 Section 6.09.
	 	Waiver of Jury Trial.	  	 	17	  
	 Section 6.10.
	 	Force Majeure.	  	 	17	  
	 Section 6.11.
	 	No Recitals, etc.	  	 	17	  
		
	EXHIBIT A Form of Note	  	 	A-1	  

  
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 SUPPLEMENTAL INDENTURE dated as of July 17, 2012 (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 Subsidiary Guarantors (as
defined herein) 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, the Subsidiary Guarantors 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 and the Subsidiary Guarantors desire and have requested the Trustee to join them 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 3.600% Senior Notes due 2022, substantially in the form attached hereto as Exhibit A
(the “Notes”), guaranteed by the Subsidiary Guarantors, 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, the Subsidiary Guarantors 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, the Subsidiary
Guarantors 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 and the Subsidiary Guarantors mutually covenant and agree 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 “3.600% Senior Notes due 2022.” The Notes shall be in the form of Exhibit A
hereto, which is hereby incorporated into this Supplemental Indenture by reference. The Notes shall be guaranteed by the Subsidiary Guarantors as provided in such form and the Indenture. 

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. 
 “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 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. 

  
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 “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. 
 “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 

  
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 (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; 
 (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 

  
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 (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.

 “Company” has the meaning provided in the Indenture. 

“Comparable Treasury Issue” means the U.S. Treasury security selected by an Independent Investment Banker as having a
maturity comparable to the remaining term of the Notes to be redeemed that would be used, at the time of selection and in accordance with customary financial practice, in pricing new issues of corporate debt securities of comparable maturity to the
remaining term of the Notes to be redeemed. 
 “Comparable Treasury Price” means, with respect to any
Redemption Date, (a) the average of the Reference Treasury Dealer Quotations for the Redemption Date, after excluding the highest and lowest of such Reference Treasury Dealer Quotations, or (b) if the Independent Investment Banker obtains
fewer than four such Reference Treasury Dealer Quotations, the average of all quotations obtained. 
 “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 capital 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. 

  
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 “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. 
 “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. 

“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.

 “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. 

“Independent Investment Banker” means one of the Reference Treasury Dealers appointed by the Company. 

“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. 
 “Paying Agent” means The Bank of New York Mellon Trust Company, N.A. or any
successor paying agent. 

  
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 “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 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. 
 “Reference Treasury
Dealer” means each of Deutsche Bank Securities Inc., Merrill Lynch, Pierce, Fenner & Smith Incorporated and Morgan Stanley & Co. LLC, and their respective successors, and one other nationally recognized investment banking
firm that is a primary U.S. government securities dealer specified from time to time by the Company. If, however, any of them shall cease to be a primary U.S. government securities dealer, the Company will substitute another nationally recognized
investment banking firm that is such a dealer. 
 “Reference Treasury Dealer Quotations” means, with respect to
each Reference Treasury Dealer and any Redemption Date, the average, as determined by the Independent Investment Banker, of the bid and asked prices for the Comparable Treasury Issue (expressed in each case as a percentage of its principal amount)
quoted in writing to the Independent Investment Banker by such Reference Treasury Dealer as of 5:00 p.m., New York time, on the third Business Day preceding the Redemption Date. 

“Registrar” means The Bank of New York Mellon Trust Company, N.A., or any successor registrar of the Notes. 

  
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 “Remaining Scheduled Payments” means the remaining scheduled payments of
the principal of and interest on each Note to be redeemed that would be due after the related Redemption Date but for such redemption. 
 “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 Standard & Poor’s Ratings Services, a division of The McGraw-Hill Companies, 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. 
 “Subsidiary
Guarantors” means: 
 (1) each of the Subsidiaries of the Company listed on Schedule A to this
Supplemental Indenture; and 
 (2) any other Subsidiary that executes a Guarantee in accordance with the
provisions of this Supplemental Indenture; 
 and their respective successors and assigns; provided that any Person constituting a
Subsidiary Guarantor as described above shall cease to constitute a Subsidiary Guarantor when its respective Guarantee is released in accordance with the terms of this Supplemental Indenture. 

“Supplemental Indenture” has the meaning provided in the Preamble. 

“Treasury Rate” means, for any Redemption Date, the rate per annum equal to the semi-annual equivalent yield to
maturity, computed as of the second Business Day immediately preceding that Redemption Date, of the Comparable Treasury Issue, assuming a price for the Comparable Treasury Issue (expressed as a percentage of its principal amount) equal to the
Comparable Treasury Price for that Redemption Date. 

  
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 “Trustee” has the meaning provided in the Preamble. 

“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.	Redemption at the Option of the Company. 

 (a) The Company may redeem the Notes, in whole or in part, at any time and from time to time prior to April 15, 2022, 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 $2,000, for a Redemption Price equal to: 
 (i) 100% of the principal amount of the Notes to be redeemed; and 

(ii) the sum, as determined by an Independent Investment Banker, of the present values of the Remaining Scheduled Payments
on the Notes being redeemed (excluding accrued and unpaid interest to the Redemption Date), discounted to the Redemption Date on a semiannual basis (assuming a 360-day year consisting of twelve 30-day months) at the Treasury Rate plus 35 basis
points, 
 plus, in each case, accrued and unpaid interest to the Redemption Date. 

(b) The Company may redeem the Notes, in whole or in part, at any time and from time to time on or after April 15, 2022, 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 $2,000, at a Redemption Price equal to 100% of the principal amount of the Notes
being redeemed plus accrued and unpaid interest to the Redemption Date. 
 (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. 

  
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 (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 April 15, 2022, the Company shall give the Trustee notice of the related Redemption Price promptly after the calculation thereof and the Trustee
shall not have any responsibility for such calculation. 
 ARTICLE FOUR 

Covenants 

The following covenants are added to the Indenture for the benefit of Holders: 

 

	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 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; 

  
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 (c) Mortgages in favor of the Company or any Subsidiary Guarantor;

 (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 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 

  
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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 by an Officers’ Certificate) 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 $2,000 or an integral multiple of $1,000 in excess thereof.

  
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 (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 send, by first class mail, a notice to each Holder, 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 mailed, 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 mailed 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; 
 (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 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 

  
 -13-

 
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. 
  

	Section 4.11.	Additional Guarantees. 

If, after the date of this Supplemental Indenture, any Domestic Subsidiary that is not already a Subsidiary Guarantor (including, without
limitation, any Domestic Subsidiary acquired or created after the date of this Supplemental Indenture) guarantees any Debt in excess of $5 million of either the Company or a Subsidiary Guarantor, then in either case that Subsidiary shall become a
Subsidiary Guarantor by executing a supplemental indenture and delivering it to the Trustee within 15 Business Days of the date on which it guaranteed such Debt. 
 ARTICLE FIVE 
 Guarantee 

 

	Section 5.01.	Release of Subsidiary Guarantors from Guarantee. 

 Section 10.04 of the Indenture shall be amended by replacing that section of the Indenture with the following, but only with respect to the Notes: 

(a) Notwithstanding any other provisions of this Indenture, the Guarantee of any Subsidiary Guarantor may be released upon
the terms and subject to the conditions set forth in this Section 10.04. Provided that no Event of Default shall have occurred and shall be continuing under this Indenture, any Guarantee incurred by a Subsidiary Guarantor pursuant to this
Article X shall be unconditionally released and discharged automatically: 
 (i) upon any sale or other
disposition of all or substantially all of the assets of that Subsidiary Guarantor (including by way of merger or consolidation) to a Person that is not (either before or after giving effect to such transaction) the Company or a Subsidiary;

 (ii) upon any sale or other disposition of all of the Capital Stock of a Subsidiary Guarantor to a Person that
is not (either before or after giving effect to such transaction) the Company or a Subsidiary; 

  
 -14-

 (iii) upon legal defeasance or satisfaction and discharge of the Notes as
provided in Article VIII; or 
 (iv) at such time as such Subsidiary Guarantor ceases to guarantee any other Debt
of the Company or a Subsidiary Guarantor in excess of $5 million. 
 (b) The Trustee shall deliver an appropriate
instrument evidencing any release of a Subsidiary Guarantor from its Guarantee upon receipt of a written request of the Company accompanied by an Officers’ Certificate and an Opinion of Counsel to the effect that the Subsidiary Guarantor is
entitled to such release in accordance with the provisions of this Indenture. If the Subsidiary Guarantor is not so released it shall remain liable for the full amount of principal of (and premium, if any, on) and interest on the Notes, subject to
the limitations of Section 10.03. 
 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, any Subsidiary Guarantor or the
Trustee, as such, shall not have any liability for any obligations of the Company under the Notes, for any obligations of any Subsidiary Guarantor under any Guarantee, or for any obligations of the Company, any Subsidiary Guarantor 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, the Notes and the related Guarantees. 
  

	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 Subsidiary Guarantor or a Subsidiary. Any such indenture,
loan or debt agreement may not be used to interpret this Supplemental Indenture. 

  
 -15-

	Section 6.04.	Successors and Assigns. 

All covenants and agreements of the Company and each of the Subsidiary Guarantors 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 or in any Guarantee of a Subsidiary Guarantor 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. 
  

	Section 6.07.	Amendments Without Consent of Holders. 

 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. 

 

	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 or any Subsidiary
Guarantor 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. 

  
 -16-

	Section 6.09.	Waiver of Jury Trial. 

Each of the Company, the Subsidiary Guarantors 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 and the
Subsidiary Guarantors. 

  
 -17-

 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 Sixth Supplemental Indenture] 

 SUBSIDIARY GUARANTORS: 

 

			
	Geismar Holdings, Inc.
	 GVGP, Inc.

Westlake Chemical Investments, Inc.

	Westlake Development Corporation
	 Westlake Ethylene Pipeline Corporation
 Westlake Geismar Power Company LLC

		 	 By Westlake Vinyls Company LP,
its Manager

		 	 By GVGP, Inc.,
its General Partner

	Westlake Longview Corporation
	 Westlake Management Services, Inc.
 Westlake NG I Corporation

	Westlake NG IV Corporation
	 Westlake NG V Corporation
 Westlake Olefins Corporation
 Westlake Petrochemicals LLC,

		 	 By Westlake Chemical Investments, Inc.,
its Manager

	Westlake Pipeline Investments LLC,
		 	 By Westlake Chemical Investments, Inc.,
its Manager

	Westlake Polymers LLC,
		 	 By Westlake Chemical Investments, Inc.,
its Manager

	Westlake PVC Corporation
	 Westlake Resources Corporation
 Westlake Styrene LLC,

		 	 By Westlake Chemical Investments, Inc.,
its Manager

	Westlake Supply and Trading Company
	Westlake Vinyl Corporation
	Westlake Vinyls Company LP,
		 	 By GVGP, Inc.,
its General Partner

	Westlake Vinyls, Inc.
	WPT LLC,
		 	 By Westlake Chemical Investments, Inc.
its Manager

		
	By:	 	 /s/ Albert Chao

			
	Name:	 	Albert Chao
	Title:	 	President

  
 [Signature
Page to Sixth Supplemental Indenture] 

			
	North American Pipe Corporation
	Westech Building Products, Inc.
		
	By:	 	 /s/ Robert F. Buesinger

			
	Name:	 	Robert F. Buesinger
	Title:	 	President

  
 [Signature
Page to Sixth Supplemental Indenture] 

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

					
	 as Trustee

		
	By:	 	 /s/ Julie Hoffman-Ramos

		 	Name:	 	Julie Hoffman-Ramos
		 	Title:	 	Vice President

  
 [Signature
Page to Sixth Supplemental Indenture] 

 Schedule A 
 Subsidiary Guarantors 
 Geismar Holdings, Inc. 

GVGP, Inc. 
 North American Pipe Corporation

 Westech Building Products, Inc. 

Westlake Chemical Investments, Inc. 
 Westlake
Development Corporation 
 Westlake Ethylene Pipeline Corporation 
 Westlake Geismar Power Company LLC 
 Westlake Longview Corporation 

Westlake Management Services, Inc. 
 Westlake
NG I Corporation 
 Westlake NG IV Corporation 
 Westlake NG V Corporation 
 Westlake Olefins Corporation 

Westlake Petrochemicals LLC 
 Westlake Pipeline
Investments LLC 
 Westlake Polymers LLC 
 Westlake PVC Corporation 
 Westlake Resources Corporation 

Westlake Styrene LLC 
 Westlake Supply and
Trading Company 
 Westlake Vinyl Corporation 
 Westlake Vinyls Company LP 
 Westlake Vinyls, Inc. 

WPT LLC 

  
 [Signature
Page to Sixth Supplemental Indenture] 

 EXHIBIT A 

FORM 
 OF

 3.600% SENIOR NOTE DUE 2022 

  
 A-1

 [FORM OF FACE OF NOTE] 

[If this Note is to be a Global Security, insert — THIS NOTE IS A GLOBAL SECURITY WITHIN THE MEANING OF THE INDENTURE HEREINAFTER
REFERRED TO AND IS REGISTERED IN THE NAME OF THE DEPOSITORY TRUST COMPANY (55 WATER STREET, NEW YORK, NEW YORK) OR OTHER DULY APPOINTED DEPOSITORY (THE “DEPOSITARY”) OR THEIR RESPECTIVE NOMINEES. 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 DEPOSITORY TRUST COMPANY 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 The Depository Trust Company, a New York corporation, to the issuer hereof or its agent for registration of transfer, exchange, or
payment, and any certificate issued is registered in the name of Cede & Co. or in such other name as is requested by an authorized representative of The Depository Trust Company (and any payment is made to Cede & Co. or to such
other entity as is requested by an authorized representative of The Depository Trust Company), ANY TRANSFER, PLEDGE, OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede &
Co., has an interest herein.] 
  

			
	NO.         	  	CUSIP NO. 960413 AF9

 WESTLAKE CHEMICAL CORPORATION 

3.600% SENIOR NOTE DUE 2022 
  

			
		
	Principal Amount:	  	$250,000,000
		
	Regular Record Date:	  	January 1 or July 1 (whether or not a Business Day), as the case may be, next preceding the applicable Interest Payment Date
		
	Original Issue Date:	  	July 17, 2012
		
	Stated Maturity:	  	July 15, 2022
		
	Interest Payment Dates:	  	January 15 and July 15, commencing January 15, 2013
		
	Interest Rate:	  	3.600% per annum
		
	Authorized Denomination:	  	$2,000 and integral multiples of $1,000 in excess thereof

  
 A-2

 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, semiannually in arrears on each Interest Payment Date as specified above, commencing on January 15, 2013 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 
 3.600% Senior Note due 2022

 This Note is one of a duly authorized issue of 3.600% Senior Notes due 2022 (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 semi-annually in arrears on January 15 and July 15 of each year, commencing January 15, 2013.
Interest will be paid on each such Interest Payment Date to the Persons who are registered Holders of the Notes at the close of business on the January 1 or July 1 (whether or not a Business Day) next preceding the Interest Payment Date
(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, 2012. Interest will be computed on the basis of a
360-day year of twelve 30-day months. 
  

	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 United States of America that at the time of payment is legal tender for payment of public and private debts. The Company will make such payments
(i) by wire transfer of immediately available funds to any account maintained in the United States with respect to Notes evidenced by Global Securities and any other Notes with any aggregate principal amount in excess of $1,000,000 the Holder
of which has provided wire transfer instructions to the Paying Agent at least five Business Days prior to the applicable payment date 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 Paying Agent and Registrar at its office at 601 Travis Street, 16th Floor, Houston, Texas 77002.
The Company may appoint and change any Paying Agent or Registrar without notice to any Holder. The Company, any Subsidiary Guarantor 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 Sixth Supplemental Indenture dated as of July 17, 2012 (the “Sixth Supplemental Indenture,” and together
with the Base Indenture, the “Indenture”) among the Company, the Subsidiary Guarantors 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 $250,000,000. 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, in whole or in part, at any time and from time to time prior to April 15, 2022, 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 $2,000, for a Redemption Price equal to: 
  

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

  

	 	(b)	the sum, as determined by an Independent Investment Banker, of the present values of the Remaining Scheduled Payments on the Notes being redeemed (excluding accrued and
unpaid interest to the Redemption Date), discounted to the Redemption Date on a semiannual basis (assuming a 360-day year consisting of twelve 30-day months) at the Treasury Rate plus 35 basis points, 

plus, in each case, accrued and unpaid interest to the Redemption Date. 
 The Company may redeem the Notes, in whole or in part, at any time and from time to time on or after April 15, 2022, 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 $2,000, at a Redemption Price equal to 100% of the principal amount of the Notes being redeemed plus accrued and unpaid interest to the Redemption Date.

  
 A-6

	6.	Mandatory Redemption. 

The Company will not be required to make mandatory redemption or sinking fund payments with respect to the Notes. 

 

	7.	Notice of Redemption. 

The Company shall mail notice of a redemption not less than 30 days nor more than 60 days before the Redemption Date to Holders of Notes
to be redeemed. Once notice of redemption is mailed, 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 $2,000 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, 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 $2,000 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 mailing of the relevant notice of redemption or repurchase and ending on the close of business on the day of mailing such notice. 

  
 A-7

	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, the Subsidiary
Guarantors 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 or any Subsidiary Guarantor 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; (ix) waive a
continuing Default or Event of Default in the payment of principal of or premium (if any) or interest on the Securities or (x) except as provided in the Indenture, release any Subsidiary Guarantor or modify the related Guarantee in any manner
materially adverse to the Holders. 
 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 or any Subsidiary Guarantor to 

  
 A-8

 
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; (iv) certain
events of bankruptcy or insolvency with respect to the Company or any Subsidiary Guarantors that are Significant Subsidiaries and (viii) except as permitted by the Indenture, any Guarantee of the Notes ceases to be in full force and effect or
is declared null and void in a judicial proceeding or any Subsidiary Guarantor denies or disaffirms its obligations under the Indenture and the Guarantee (other than by reason of release of a Subsidiary Guarantor from its Guarantee in accordance
with the terms of the Indenture and the Guarantee). 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 U.S. Government Obligations sufficient for such payment as provided in the Indenture. 
  

	15.	No Recourse Against Others. 

 A director, officer, member, manager, employee, stockholder, partner or other owner of the Company, any Subsidiary Guarantor or the Trustee, as such, shall not have any liability for any obligations of
the Company under the Notes, for any obligations of any Subsidiary Guarantor under any Guarantee, or for any obligations of the Company, any Subsidiary Guarantor 

  
 A-9

 
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 Numbers. 

 Pursuant
to a recommendation promulgated by the Committee on Uniform Security Identification Procedures, the Company has caused CUSIP numbers to be printed on the Notes and the Trustee may use CUSIP 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 
 If you the Holder want to assign this Security, fill in the form below: 
 I or we assign and
transfer this Security to 
  
  

 
  
 (Insert assignee’s social security or tax ID number) 
  

 
  

 
  

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

 
  
 agent to transfer this Security 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 Security)

 

			
	Signature Guarantee:	 	  

		 	Signature must be guaranteed by participant in a recognized Signature Guarantee Medallion Program (or other signature guarantee program reasonably acceptable to the
Trustee)

  
 A-11

 [FORM OF NOTATION ON SECURITY RELATING TO GUARANTEE] 

NOTATION OF GUARANTEE 
 The
undersigned (the “Subsidiary Guarantors”) have unconditionally guaranteed, jointly and severally (such guarantee by each Subsidiary Guarantor being referred to herein as the “Guarantee”), (i) the due and
punctual payment of the principal of and premium, if any, and interest on the Notes, whether at maturity, by acceleration or otherwise, the due and punctual payment of interest on the overdue principal and interest, if any, on the Notes, to the
extent lawful, and the due and punctual performance of all other obligations of the Company to the Holders or the Trustee all in accordance with, and subject to the limitations of, the terms set forth in Article X of the Indenture and (ii) in
case of any extension of time of payment or renewal of any Notes or any of such other obligations, that the same will be promptly paid in full when due or performed in accordance with the terms of the extension or renewal, whether at stated
maturity, by acceleration or otherwise. 
 No past, present or future stockholder, officer, director, member, manager, partner, employee or
incorporator, as such, of any of the Subsidiary Guarantors shall have any liability under the Guarantee by reason of such person’s status as stockholder, officer, director, member, manager, partner, employee or incorporator. Each Holder of a
Note by accepting a Note waives and releases all such liability. This waiver and release are part of the consideration for the issuance of the Guarantees. 
 Each Holder of a Note by accepting a Note agrees that any Subsidiary Guarantor named below shall have no further liability with respect to its Guarantee if such Subsidiary Guarantor otherwise ceases to be
liable in respect of its Guarantee in accordance with the terms of the Indenture. 

  
 A-12

 The Guarantee shall not be valid or obligatory for any purpose until the certificate of authentication on
the Notes upon which the Guarantee is noted shall have been executed by the Trustee under the Indenture by the manual signature of one of its authorized officers. 

 

			
	Geismar Holdings, Inc.
	 GVGP, Inc.

Westlake Chemical Investments, Inc.

	Westlake Development Corporation
	 Westlake Ethylene Pipeline Corporation
 Westlake Geismar Power Company LLC

		 	 By Westlake Vinyls Company LP,
its Manager

		 	 By GVGP, Inc.,
its General Partner

	Westlake Longview Corporation
	 Westlake Management Services, Inc.
 Westlake NG I Corporation

	Westlake NG IV Corporation
	 Westlake NG V Corporation
 Westlake Olefins Corporation
 Westlake Petrochemicals LLC,

		 	 By Westlake Chemical Investments, Inc.,
its Manager

	Westlake Pipeline Investments LLC,
		 	 By Westlake Chemical Investments, Inc.,
its Manager

	Westlake Polymers LLC,
		 	 By Westlake Chemical Investments, Inc.,
its Manager

	Westlake PVC Corporation
	 Westlake Resources Corporation
 Westlake Styrene LLC,

		 	 By Westlake Chemical Investments, Inc.,
its Manager

	Westlake Supply and Trading Company
	Westlake Vinyl Corporation
	Westlake Vinyls Company LP,
		 	 By GVGP, Inc.,
its General Partner

	Westlake Vinyls, Inc.
	WPT LLC,
		 	 By Westlake Chemical Investments, Inc.
its Manager

		
	By:	 	  

			
	Name:	 	Albert Chao
	Title:	 	President

  
 A-13

 
			
	North American Pipe Corporation
	Westech Building Products, Inc.
		
	By:	 	  

			
	Name:	 	Robert F. Buesinger
	Title:	 	President

  
 A-14Amendment No. 1 to Rights Agreement

 Exhibit 4.1 
 AMENDMENT NO. 1 TO RIGHTS AGREEMENT 
 This AMENDMENT NO. 1 (this
“Amendment”) to the Rights Agreement dated as of May 16, 2012 (the “Rights Agreement”) between Human Genome Sciences, Inc., a Delaware corporation (the “Company”), and American Stock
Transfer & Trust Company, LLC, as rights agent (the “Rights Agent”), is entered into as of July 16, 2012. Capitalized terms used in this Amendment and not otherwise defined herein shall have the meanings given to them
in the Rights Agreement. 
 WITNESSETH: 
 WHEREAS, the Board of Directors of the Company (the “Board”) has determined that it is in the best interests of the Company and its stockholders to amend the Rights Agreement as set forth
herein immediately prior to and in connection with the execution of the Agreement and Plan of Merger, dated as of July 16, 2012 (as amended, modified or supplemented, from time to time, the “Merger Agreement”), by and among
GlaxoSmithKline plc, a public limited company organized under the laws of England and Wales (“Parent“), H. Acquisition Corp., a Delaware corporation and a wholly-owned subsidiary of Parent (“Merger Sub“), and the
Company, pursuant to which Merger Sub will be merged with and into the Company (the “Merger”), with the Company surviving the Merger as a wholly-owned subsidiary of Parent; 
 WHEREAS, the Company desires to amend the Rights Agreement pursuant to Section 5.4 of the Rights Agreement, immediately prior to entering into the Merger Agreement, to facilitate the transactions
contemplated by the Merger Agreement; 
 WHEREAS, pursuant to Section 5.4 of the Rights Agreement, the Company has delivered to the Rights
Agent a certificate signed by an appropriate officer of the Company which states that this Amendment is in compliance with the terms of Section 5.4(a) of the Rights Agreement; and 
 WHEREAS, pursuant to resolutions adopted at a duly convened special meeting of the Board held on July 16, 2012, the Board has determined that it is in the best interests of the Company and its
stockholders, and consistent with the objectives of the Board in adopting the Rights Agreement, to amend the Rights Agreement in the manner set forth herein immediately prior to entering into the Merger Agreement to except from the operation of the
Rights Agreement the Merger Agreement, the Offer, Merger and Top-Up Option (as such terms are defined in the Merger Agreement), and any and all other transactions contemplated by the Merger Agreement and to provide that the Rights Agreement shall
expire immediately prior to the effective time of the Merger. 

 NOW, THEREFORE, in consideration of the foregoing and the mutual agreements herein set
forth, the parties hereby agree as follows: 
  

	1.	Amendment to Section 1.1 

  

	 	a.	The definition of “Acquiring Person” in Section 1.1 of the Rights Agreement is hereby amended by adding the following sentence to the end of said
definition: 

 “Notwithstanding anything in this Agreement to the contrary, none of Parent, Merger Sub or any
of their respective Affiliates or Associates shall be or become an Acquiring Person, and the term “Acquiring Person” shall not include any of Parent, Merger Sub or any of their respective Affiliates or Associates, solely by reason of
(i) the approval, execution, delivery, performance or public announcement of the Merger Agreement (including any amendments or supplements thereto), (ii) the consummation or public announcement of the Offer, Merger or Top-Up Option or
(iii) the consummation of any of the other transactions contemplated by the Merger Agreement.” 
  

	 	b.	The definition of “Expiration Time” in Section 1.1 of the Rights Agreement is hereby deleted in its entirety and replaced with the following:

 ““Expiration Time” shall mean the earliest of (i) the Exchange Time,
(ii) the Redemption Time, (iii) the close of business on the twelve-month anniversary of the Record Time, and (iv) the Effective Time of the Merger in accordance with the terms of the Merger Agreement.” 

 

	 	c.	The definition of “Flip-in Date” in Section 1.1 of the Rights Agreement is hereby amended by adding the following sentence to the end of said definition:

 “Notwithstanding anything in this Agreement to the contrary, no Flip-in Date shall be deemed to have
occurred solely as a result of (i) the approval, execution, delivery, performance or public announcement of the Merger Agreement (including any amendments or supplements thereto), (ii) the consummation or public announcement of the Offer,
Merger or Top-Up Option or (iii) the consummation of any of the other transactions contemplated by the Merger Agreement.” 
  

	 	d.	The definition of “Flip-over Transaction or Event” in Section 1.1 of the Rights Agreement is hereby amended by adding the following sentence to the end
of said definition: 

 “Notwithstanding anything in this Agreement to the contrary, a Flip-over Transaction
or Event shall be deemed not to have occurred, and the provisions of such section shall not be made or given effect, solely as a result of (i) the approval, execution, delivery, performance or public announcement of the Merger Agreement
(including any amendments or supplements thereto), (ii) the consummation or public announcement of the Offer, Merger or Top-Up Option or (iii) the consummation of any of the other transactions contemplated by the Merger Agreement.”

  
 2 

	 	e.	The definition of “Separation Time” in Section 1.1 of the Rights Agreement is hereby amended by adding the following sentence to the end of said
definition: 

 “Notwithstanding anything in this Agreement to the contrary, no Separation Time shall be
deemed to have occurred solely as a result of (i) the approval, execution, delivery, performance or public announcement of the Merger Agreement (including any amendments or supplements thereto), (ii) the consummation or public announcement
of the Offer, Merger or Top-Up Option or (iii) the consummation of any of the other transactions contemplated by the Merger Agreement.” 
  

	 	f.	The definition of “Stock Acquisition Date” in Section 1.1 of the Rights Agreement is hereby amended by adding the following sentence to the end of said
definition: 

 “Notwithstanding anything in this Agreement to the contrary, no Stock Acquisition Date shall
be deemed to have occurred solely as a result of (i) the approval, execution, delivery, performance or public announcement of the Merger Agreement (including any amendments or supplements thereto), (ii) the consummation or public
announcement of the Offer, Merger or Top-Up Option or (iii) the consummation of any of the other transactions contemplated by the Merger Agreement.” 
  

	 	g.	Section 1.1 of the Rights Agreement is hereby amended by inserting each of the following definitions in its appropriate alphabetical order in Section 1.1:

 “Effective Time” shall mean the time at which the Merger becomes effective pursuant to
the terms and conditions of the Merger Agreement. 
 “Merger” shall have the meaning ascribed to such
term in the Merger Agreement. 
 “Merger Agreement” shall mean that certain Agreement and Plan of Merger
by and among Parent, Merger Sub and the Company, dated as of July 16, 2012 (as such agreement may be amended from time to time). 
 “Merger Sub” means H. Acquisition Corp., a Delaware corporation and wholly-owned subsidiary of Parent. 
 “Offer” shall have the meaning ascribed to such term in the Merger Agreement. 
 “Parent” means GlaxoSmithKline plc, a public limited company organized under the laws of England and Wales. 

“Top-Up Option” shall have the meaning ascribed to such term in the Merger Agreement.” 

  
 3 

	2.	Amendment to Section 3.1 

Section 3.1 of the Rights Agreement is hereby amended by adding the following sentence to the end of Section 3.1(a): 

“Notwithstanding anything in this Agreement to the contrary, none of (i) the approval, execution, delivery, performance or
public announcement of the Merger Agreement (including any amendments or supplements thereto), (ii) the consummation or public announcement of the Offer, Merger or Top-Up Option or (iii) the consummation of any of the other transactions
contemplated by the Merger Agreement shall cause the Rights to be adjusted or become exercisable in accordance with this Section 3.1(a).” 
  

	3.	Amendment to Section 3.2 

Section 3.2 of the Rights Agreement is hereby amended by adding the following sentence to the end of Section 3.2(a): 

“Notwithstanding anything in this Agreement to the contrary, the provisions of Section 3.2(a) shall not be applicable to the
Offer, Merger or Top-Up Option.” 
  

	4.	Amendment to Section 5.2 

Section 5.2 of the Rights Agreement is hereby amended by adding the following sentence to the end of Section 5.2: 

“For the avoidance of doubt, this Agreement shall expire immediately prior to the Effective Time of the Merger in accordance with the
terms of the Merger Agreement.” 
  

	5.	Benefits 

 All of the covenants and
provisions of this Amendment by or for the benefit of the Company or the Rights Agent shall bind and inure to the benefit of their respective successors and assigns hereunder. 

 

	6.	Severability 

 If any term, provision,
covenant or restriction of this Amendment is held by a court of competent jurisdiction or other authority to be invalid, void or unenforceable, the remainder of the terms, provisions, covenants and restrictions of this Amendment shall remain in full
force and effect and shall in no way be affected, impaired or invalidated. 
  

	7.	Effectiveness and Effect of Amendment 

  

	 	a.	Notwithstanding anything to the contrary set forth in Section 5.4, this Amendment shall become effective as of the date first written above, but such effectiveness
is contingent upon the execution and delivery of the Merger Agreement by the parties thereto. The Company shall notify the Rights Agent via electronic mail of such execution and delivery of the Merger Agreement promptly thereafter.

  
 4 

	 	b.	Except as specifically modified herein, the Rights Agreement shall not otherwise be supplemented or amended by virtue of this Amendment, but shall remain in full force
and effect. The execution, delivery and effectiveness of this Amendment shall not, except as expressly provided herein, constitute a waiver or amendment of any provision of the Rights Agreement. Upon and after the effectiveness of this Amendment,
each reference in the Rights Agreement to “this Agreement,” “hereunder,” “hereof” or words of like import referring to the Rights Agreement, and each reference in any other document to “the Rights Agreement,”
“thereunder,” “thereof” or words of like import referring to the Rights Agreement, shall mean and be a reference to the Rights Agreement as modified hereby. 

 

	8.	Governing Law 

 This Amendment shall be
deemed to be a contract made under the laws of the State of Delaware and for all purposes shall be governed by and construed in accordance with the laws of the State of Delaware applicable to contracts made and to be performed entirely within State
of Delaware. 
  

	9.	Descriptive Headings 

 Descriptive
headings of the several sections of this Amendment are inserted for convenience only and shall not control or affect the meaning or construction of any of the provisions hereof. 

 

	10.	Counterparts 

 This Amendment may be
executed in any number of counterparts and each of such counterparts shall for all purposes be deemed to be an original, and all such counterparts shall together constitute but one and the same instrument. A signature to this Amendment transmitted
electronically shall have the same authority, effect, and enforceability as an original signature. 
 [Signature Page Follows]

  
 5 

 IN WITNESS WHEREOF, the parties have executed this Amendment as of the date set forth in the
first paragraph hereof. 
  

			
	Human Genome Sciences, Inc.
		
	By:	 	/s/ H. Thomas Watkins
	Name: H. Thomas Watkins
	Title: President and Chief Executive Officer
	
	American Stock Transfer & Trust Company, LLC
		
	By:	 	/s/ Mike Nespoli
	Name: Mike Nespoli
	Title: Senior Vice President, Relationship Manager

  
 6

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