Westlake PVC 424B5 Prospectus supplement for primary offering

This preliminary prospectus supplement and the accompanying prospectus relate to an effective registration statement under the Securities Act of 1933, but are not complete and may be changed. This preliminary prospectus supplement and the accompanying prospectus are not an offer to sell these securities and are not soliciting an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

Filed Pursuant to Rule 424(b)(5)
Registration No. 333-177119

Subject to Completion

Preliminary Prospectus Supplement dated July 10, 2012

PROSPECTUS    SUPPLEMENT

(To prospectus dated September 30, 2011)

$250,000,000

Westlake Chemical Corporation

% Senior Notes due 2022

We are offering $250,000,000 aggregate principal amount of our     % Senior Notes due 2022. The notes will bear interest at the rate of     % per year. We will pay interest on the notes on             and             of each year, beginning                     , 2013. The notes will mature on                     , 2022. We may redeem the notes in whole or in part at any time at the applicable redemption prices set forth under the caption “Description of the Notes—Optional Redemption.” If a change of control triggering event as described in this prospectus supplement under the caption “Description of the Notes—Change of Control Triggering Event” occurs, we will be required, unless we have exercised our right to redeem the notes, to offer to purchase the notes from the holders.

The notes will be our senior unsecured obligations and will rank equally in right of payment with all of our other senior unsecured indebtedness from time to time outstanding. The notes will be effectively subordinated to our secured indebtedness to the extent of the value of the assets securing such indebtedness and to the indebtedness and other liabilities of our non-guarantor subsidiaries. The notes will be fully and unconditionally guaranteed, on a joint and several basis, by our existing and future domestic subsidiaries that guarantee any other indebtedness of ours or another guarantor in excess of $5.0 million. The guarantees will be unsecured and unsubordinated obligations of each of the subsidiary guarantors and will rank equally with each subsidiary guarantor’s other unsecured and unsubordinated indebtedness from time to time outstanding.

The notes will be issued only in registered form in minimum denominations of $2,000 and integral multiples of $1,000 in excess thereof.

Investing in the notes involves risks that are described in the “Risk Factors” section beginning on page S-11 of this prospectus supplement.

	Per Note		Total
Public offering price (1)		%	$
Underwriting discount		%	$
Proceeds, before expenses, to us (1)		%	$

(1) Plus accrued interest, if any, from                     , 2012, if settlement occurs after that date.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement or the accompanying prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The notes will be ready for delivery in book-entry form only through the facilities of The Depository Trust Company for the accounts of its participants, including Euroclear Bank S.A./N.V., as operator of the Euroclear System, and Clearstream Banking,société anonyme, on or about                     , 2012.

Joint Book-Running Managers

BofA Merrill Lynch Deutsche Bank Securities Morgan Stanley

The date of this prospectus supplement is                     , 2012

You should rely only on the information contained or incorporated by reference in this prospectus supplement and the accompanying prospectus. We have not authorized anyone else to provide you with any additional or different information. If anyone provides you with different or inconsistent information, you should not rely on it. We are not making an offer to sell securities in any jurisdiction where the offer or sale is not permitted. The information contained in this prospectus supplement or the accompanying prospectus is current only as of the date of this prospectus supplement or the accompanying prospectus, as the case may be, and any information incorporated by reference is current only as of the date of the document incorporated by reference. Our business, financial condition, results of operations and prospects may have changed since those dates.

TABLE OF CONTENTS

Prospectus Supplement

	Page
Cautionary Statement About Forward-Looking Statements		S-1
About This Prospectus Supplement		S-3
Industry and Market Data		S-3
Production Capacity		S-3
Summary		S-4
Risk Factors		S-11
Use of Proceeds		S-14
Ratio Of Earnings To Fixed Charges		S-14
Capitalization		S-15
Description of the Notes		S-16
Material U.S. Federal Tax Consequences		S-29
Underwriting		S-34
Legal Matters		S-38
Experts		S-38
Where You Can Find More Information		S-38

Prospectus

About This Prospectus	1
About Westlake Chemical Corporation	2
The Subsidiary Guarantors	3
Risk Factors	4
Cautionary Statements about Forward-Looking Statements	8
Use of Proceeds	10
Ratio of Earnings to Fixed Charges	10
Description of Debt Securities	11
Description of Capital Stock	21
Description of Warrants	27
Selling Stockholder	28
Plan of Distribution	30
Legal Opinions	32
Experts	32
Where You Can Find More Information	32

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CAUTIONARY STATEMENT ABOUT FORWARD-LOOKING STATEMENTS

The Private Securities Litigation Reform Act of 1995 provides safe harbor provisions for forward-looking information. Certain of the statements contained in this prospectus supplement and the accompanying prospectus are forward-looking statements. All statements, other than statements of historical facts, included in this prospectus supplement and the accompanying prospectus that address activities, events or developments that we expect, project, believe or anticipate will or may occur in the future are forward-looking statements. Forward-looking statements can be identified by the use of words such as “believes,” “intends,” “may,” “should,” “could,” “anticipates,” “expected” or comparable terminology, or by discussions of strategies or trends. Although we believe that the expectations reflected in such forward-looking statements are reasonable, we cannot give any assurances that these expectations will prove to be correct. Forward-looking statements relate to matters such as:

• redemption of our 6 ⁵/8% Senior Notes due 2016;

• future operating rates, margins, cash flow and demand for our products;

• industry market outlook;

• production capacities;

• our ability to borrow additional funds under our credit facility;

• our ability to meet our liquidity needs;

• our intended quarterly dividends;

• future capacity additions and expansions in the industry;

• timing, funding and results of the expansion programs at our Lake Charles and Calvert City complexes;

• timing, funding and results of the planned new chlor-alkali plant in Geismar;

• timing and cost of repairs at the Geismar vinyls complex;

• health of our customer base;

• pension plan funding requirements and investment policies;

• compliance with present and future environmental regulations and costs associated with environmentally related penalties, capital expenditures, remedial actions and proceedings, including any new laws, regulations or treaties that may come into force to limit or control carbon dioxide and other greenhouse gases emissions or to address other issues of climate change;

• the utilization of net operating loss carryforwards;

• effects of pending legal proceedings; and

• timing of and amount of capital expenditures.

We have based these statements on assumptions and analyses in light of our experience and perception of historical trends, current conditions, expected future developments and other factors we believe were appropriate in the circumstances when the statements were made. Forward-looking statements by their nature involve substantial risks and uncertainties that could significantly impact expected results, and actual future

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results could differ materially from those described in such statements. While it is not possible to identify all factors, we continue to face many risks and uncertainties. Among the factors that could cause actual future results to differ materially are the risks and uncertainties discussed under “Risk Factors” in this prospectus supplement and the accompanying prospectus and in our most recent Annual Report on Form 10-K and the following:

• general economic and business conditions;

• the cyclical nature of the chemical industry;

• the availability, cost and volatility of raw materials and energy;

• uncertainties associated with the United States and worldwide economies, including those due to the global economic slowdown and political tensions in the Middle East and elsewhere;

• current and potential governmental regulatory actions in the United States and regulatory actions and political unrest in other countries;

• industry production capacity and operating rates;

• the supply/demand balance for our products;

• competitive products and pricing pressures;

• instability in the credit and financial markets;

• access to capital markets;

• terrorist acts;

• operating interruptions (including leaks, explosions, fires, weather-related incidents, mechanical failure, unscheduled downtime, labor difficulties, transportation interruptions, spills and releases and other environmental risks);

• changes in laws or regulations;

• technological developments;

• our ability to implement our business strategies; and

• creditworthiness of our customers.

Many of such factors are beyond our ability to control or predict. Any of the factors, or a combination of these factors, could materially affect our future results of operations and the ultimate accuracy of the forward-looking statements. These forward-looking statements are not guarantees of our future performance, and our actual results and future developments may differ materially from those projected in the forward-looking statements. Management cautions against putting undue reliance on forward-looking statements or projecting any future results based on such statements or present or prior earnings levels. Every forward-looking statement speaks only as of the date of the particular statement, and we undertake no obligation to publicly update or revise any forward-looking statement, except as required by applicable law.

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ABOUT THIS PROSPECTUS SUPPLEMENT

This document is in two parts. The first part is the prospectus supplement, which describes the specific terms of the notes we are offering and certain other matters relating to us and our financial condition. The second part, the accompanying prospectus, gives more general information about securities we may offer from time to time, some of which may not apply to the notes we are offering. You should read this prospectus supplement along with the accompanying prospectus, as well as the documents incorporated by reference. If the description of the offering varies between this prospectus supplement and the accompanying prospectus, you should rely on the information in this prospectus supplement.

In this prospectus supplement and the accompanying prospectus, “we,” “us,” and “our” refer to Westlake Chemical Corporation and its consolidated subsidiaries, unless the context indicates otherwise.

INDUSTRY AND MARKET DATA

Industry and market data used or incorporated by reference in this prospectus supplement and the accompanying prospectus were obtained through internal company research, surveys and studies conducted by unrelated third parties and industry and general publications, including information from IHS Chemical and Chemical Data, Inc. We have not independently verified market and industry data from external sources. While we believe internal company estimates are reliable and market definitions are appropriate, neither such estimates nor these definitions have been verified by any independent sources.

PRODUCTION CAPACITY

Unless we state otherwise, annual production capacity estimates used in this prospectus supplement and the accompanying prospectus represent rated capacity of the facilities at December 31, 2011. We calculated rated capacity by estimating the number of days in a typical year that a production unit is expected to operate, after allowing for downtime for regular maintenance, and multiplying that number by an amount equal to the unit’s optimal daily output based on the design feedstock mix. Because the rated capacity of a production unit is an estimated amount, actual production volumes may be more or less than the rated capacity.

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SUMMARY

This summary may not contain all of the information that may be important to you. You should read the entire prospectus supplement and accompanying prospectus, including the risk factors, as well as the documents incorporated by reference, before making an investment decision.

About Westlake Chemical Corporation

Overview

We are a vertically integrated manufacturer and marketer of basic chemicals, vinyls, polymers and fabricated building products. Our products include some of the most widely used chemicals in the world, which are fundamental to many diverse consumer and industrial markets, including flexible and rigid packaging, automotive products, coatings, residential and commercial construction as well as other durable and non-durable goods. We operate in two principal business segments, Olefins and Vinyls, and we are an integrated producer of vinyls with substantial downstream integration into polyvinyl chloride, or PVC, building products.

We began operations in 1986 after our first polyethylene plant, an Olefins segment business, near Lake Charles, Louisiana, was acquired from Occidental Petroleum Corporation. We began our vinyls operations in 1990 with the acquisition of a vinyl chloride monomer, or VCM, plant in Calvert City, Kentucky from the Goodrich Corporation. In 1992, we commenced our Vinyls segment building products operations after acquiring three PVC pipe plants. Since 1986, we have grown rapidly into an integrated producer of petrochemicals, polymers and building products. We achieved this by acquiring existing plants or constructing new plants (including our joint venture in China) and completing numerous capacity or production line expansions.

We benefit from highly integrated production facilities that allow us to process raw materials into higher value-added chemicals and building products. As of February 17, 2012, we had 11.8 billion pounds per year of aggregate production capacity at 13 manufacturing sites in North America. We also have a 59% interest in a joint venture in China that operates a vinyls facility.

We are a Delaware corporation with our principal executive offices located at 2801 Post Oak Boulevard, Suite 600, Houston, Texas 77056. Our telephone number at such address is (713) 960-9111.

Recent Developments

Redemption of 6 ⁵/8% Senior Notes due 2016

On June 29, 2012, we voluntarily called for redemption all $250 million aggregate principal amount outstanding of our 6 ⁵/8% Senior Notes due 2016 at a redemption price of 102.208% of the principal amount thereof, in accordance with the terms of the indenture governing the 2016 senior notes. Holders of redeemed 2016 senior notes will also receive accrued and unpaid interest to the redemption date, which is July 30, 2012.

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The Offering

Issuer Westlake Chemical Corporation.

Notes Offered $250,000,000 aggregate principal amount of     % Senior Notes due 2022.

Maturity Date                     , 2022.

Interest     % per year, payable semi-annually on             and             of each year, beginning on                     , 2013.

Optional Redemption We may redeem the notes at our option, in whole or in part, at any time prior to             , 2022 (three months prior to the maturity date of the notes) at a redemption price equal to the greater of:

• 100% of the principal amount of the notes being redeemed, and

• the sum of the present values of the remaining scheduled payments of principal and interest thereon (not including any portion of such payments of interest accrued as of the date of redemption), discounted to the date of redemption on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) at the Treasury Rate (as defined in “Description of the Notes— Optional Redemption”), plus              basis points,

plus accrued and unpaid interest on the notes being redeemed to the redemption date.

We may redeem the notes at our option, in whole or in part at any time on or after                     , 2022 (three months prior to the maturity date) at a redemption price equal to 100% of the principal amount of the notes to be redeemed, plus accrued and unpaid interest on the notes being redeemed to the redemption date.

Change of Control Triggering Event Upon the occurrence of a Change of Control Triggering Event (as defined under “Description of the Notes—Change of Control Triggering Event”), we will be required, unless we have exercised our right to redeem the notes, to offer to repurchase the notes at a price equal to 101% of their principal amount, plus accrued and unpaid interest to the date of repurchase.

Subsidiary Guarantees The notes will be fully and unconditionally guaranteed on a joint and several basis, by our existing and future domestic subsidiaries that guarantee any other indebtedness of ours or another guarantor in excess of $5.0 million. The Guarantors (as defined in this prospectus supplement) also guarantee our obligations under our existing credit facility and our existing senior notes.

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Ranking The notes and the subsidiary guarantees will rank:

• effectively junior in right of payment to all of our and the Guarantors’ secured indebtedness to the extent of the value of the assets securing such indebtedness and to the indebtedness and other liabilities of our non-guarantor subsidiaries;

• equal in right of payment to all of our and the Guarantors’ unsecured senior indebtedness; and

• senior in right of payment to all of our and the Guarantors’ subordinated indebtedness.

As of March 31, 2012, after giving pro forma effect to this offering and the application of the net proceeds from this offering as described under “Use of Proceeds,” the notes and the subsidiary guarantees ranked effectively:

1) junior in right of payment to:

• no secured indebtedness; and

• $14.1 million of current liabilities and $0.7 million of long-term indebtedness of our non-guarantor subsidiaries; and

2) pari passu in right of payment with $754.0 million of our and the Guarantors’ unsecured senior indebtedness.

Certain Covenants The indenture pursuant to which the notes will be issued will contain covenants that will, among other things, restrict our and certain of our subsidiaries’ ability to:

• incur certain secured indebtedness;

• engage in certain sale and leaseback transactions; and

• consolidate, merge or transfer all or substantially all of our assets.

These covenants will be subject to significant exceptions. See “Description of the Notes—Certain Covenants.”

Use of Proceeds We intend to use the net proceeds from the offering, together with cash on hand, to redeem the $250,000,000 aggregate principal amount outstanding of our 6 ⁵/8% Senior Notes due 2016 and to pay the premium in connection with such redemption.

Form and Denomination We will issue the notes in the form of one or more fully registered global notes registered in the name of the nominee of The Depository

S-6

Trust Company (“DTC”). Beneficial interests in the notes will be represented through book-entry accounts of financial institutions acting on behalf of beneficial owners as direct and indirect participants in DTC. Clearstream Banking, société anonyme and Euroclear Bank, S.A./ N.V., as operator of the Euroclear System, will hold interests on behalf of their participants through their respective U.S. depositaries, which in turn will hold such interests in accounts as participants of DTC. Except in the limited circumstances described in this prospectus supplement, owners of beneficial interests in the notes will not be entitled to have notes registered in their names, will not receive or be entitled to receive notes in definitive form and will not be considered holders of notes under the indenture. The notes will be issued only in denominations of $2,000 and integral multiples of $1,000 in excess thereof.

Further issuances We may, from time to time, without the consent of or notice to holders of the notes, issue and sell debt securities identical to the notes offered hereby in all respects (other than the issue date, and, to the extent applicable, issue price, first date of interest accrual and first interest payment date), so that such additional debt securities will be consolidated and form a single series with the notes offered hereby for all purposes, including voting.

No Prior Market The notes are new securities and there is currently no established trading market for the notes. Although the underwriters have informed us that they intend to make a market in the notes, they are not obligated to do so and may discontinue market making activities at any time without notice. Accordingly, we cannot assure you that a liquid market for the notes will develop or be maintained. We do not intend to list the notes on any securities exchange or public market or include the notes in any quotation system.

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

Governing Law New York

Risk Factors Investing in the notes involves certain risks. See “Risk Factors” beginning on page S-11 of this prospectus supplement and on page 4 of the accompanying prospectus for a description of certain risks you should consider before investing in the notes.

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Summary Consolidated Financial, Operating and Industry Data

We have provided in the table below summary consolidated financial, operating and industry data. We have derived the statement of operations data for each of the years in the three-year period ended December 31, 2011, and the balance sheet data as of December 31, 2009, 2010 and 2011, from audited consolidated financial statements incorporated by reference in this prospectus supplement and the accompanying prospectus. We have derived the statement of operations data for the three months ended March 31, 2011 and 2012, and the balance sheet data as of March 31, 2011 and 2012, from our unaudited consolidated financial statements. The historical financial information may not be indicative of our future performance. Results of operations for the three month period ended March 31, 2012 may not be indicative of the results of operations that may be achieved for the entire year. You should read this data in conjunction with the sections entitled “Management’s Discussion and Analysis of Financial Condition and Results of Operations” included in our Annual Report on Form 10-K for the fiscal year ended December 31, 2011 and in our Quarterly Report on Form 10-Q for the quarter ended March 31, 2012, and our consolidated financial statements and the related notes, which are incorporated by reference in this prospectus supplement and the accompanying prospectus.

	Year Ended December 31,									Three Months Ended March 31,
	2009			2010			2011			2011			2012
	(dollars in thousands)
Statement of Operations Data:
Net sales	$	2,325,723		$	3,171,787		$	3,619,848		$	867,252		$	1,034,867
Gross profit		195,128			482,683			559,006			167,584			172,637
Selling, general and administrative expenses		87,871			104,319			112,210			26,947			27,012
Income from operations		107,257			378,364			446,796			140,637			145,625
Interest expense		(34,957	)		(39,875	)		(50,992	)		(12,920	)		(12,177	)
Other income, net		6,453			4,471			5,628			1,207			1,347
Income before income taxes		78,753			342,960			401,432			128,924			134,795
Provision for income taxes		25,758			121,567			142,466			45,380			46,982
Net income	$	52,995		$	221,393		$	258,966		$	83,544		$	87,813
Balance Sheet Data (end of period):
Cash and cash equivalents	$	245,592		$	630,299		$	825,901		$	654,503		$	895,142
Working Capital (1)		701,812			1,152,382			1,391,561			1,263,980			1,483,913
Total assets		2,446,356			2,954,144			3,266,821			3,006,868			3,330,047
Long-term debt		515,400			764,482			764,563			764,502			764,583
Stockholders’ equity		1,284,982			1,505,070			1,756,312			1,594,507			1,863,030
Other Operating Data:
Cash flow from:
Operating activities	$	235,522		$	283,284		$	362,296		$	40,660		$	110,057
Investing activities		(103,186	)		(80,275	)		(202,785	)		(28,223	)		(67,182	)
Financing activities		23,017			181,698			36,091			11,777			26,366
Depreciation and amortization		123,199			128,732			131,397			32,578			35,394
Capital expenditures		99,769			81,269			176,843			28,808			64,902
EBITDA (2)		236,909			511,567			583,821			174,422			182,366
Net External Sales:
Olefins Segment
Polyethylene	$	1,210,706		$	1,656,203		$	1,772,144		$	446,703		$	445,420
Ethylene, styrene and other		400,745			605,009			795,698			158,377			286,851
Vinyls Segment
PVC, caustic soda and other		398,825			558,156			757,312			191,857			214,383
Building products		315,447			352,419			294,692			70,315			88,213

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(1) Working capital equals current assets less current liabilities.

(2) EBITDA (a non-GAAP financial measure) is calculated as net income before interest expense, income taxes, depreciation and amortization. The body of accounting principles generally accepted in the United States is commonly referred to as “GAAP.” For this purpose, a non-GAAP financial measure is generally defined by the Securities and Exchange Commission (the “SEC”) as one that purports to measure historical and future financial performance, financial position or cash flows, but excludes or includes amounts that would not be so adjusted in the most comparable GAAP measures. We have included EBITDA in this prospectus supplement because our management considers it an important supplemental measure of our performance and believes that it is frequently used by securities analysts, investors and other interested parties in the evaluation of companies in our industry, some of which present EBITDA when reporting their results. We regularly evaluate our performance as compared to other companies in our industry that have different financing and capital structures and/or tax rates by using EBITDA. EBITDA allows for meaningful company-to-company performance comparisons by adjusting for factors such as interest expense, depreciation and amortization and taxes, which often vary from company to company. In addition, we utilize EBITDA in evaluating acquisition targets. Management also believes that EBITDA is a useful tool for measuring our ability to meet our future debt service, capital expenditures and working capital requirements, and EBITDA is commonly used by us and our investors to measure our ability to service indebtedness. EBITDA is not a substitute for the GAAP measures of earnings or of cash flow and is not necessarily a measure of our ability to fund our cash needs. In addition, it should be noted that companies calculate EBITDA differently and, therefore, EBITDA as presented in this prospectus supplement may not be comparable to EBITDA reported by other companies. EBITDA has material limitations as a performance measure because it excludes (1) interest expense, which is a necessary element of our costs and ability to generate revenues because we have borrowed money to finance our operations, (2) depreciation, which is a necessary element of our costs and ability to generate revenues because we use capital assets and (3) income taxes, which is a necessary element of our operations. We compensate for these limitations by relying primarily on our GAAP results and using EBITDA only supplementally. The following table reconciles EBITDA to net income and to cash flow from operating activities.

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Reconciliation of EBITDA to Net Income and to Cash Flow from Operating Activities

	Year Ended December 31,									Three Months Ended March 31,
	2009			2010			2011			2011			2012
	(dollars in thousands)
EBITDA	$	236,909		$	511,567		$	583,821		$	174,422		$	182,366
Less:
Provision for income tax		25,758			121,567			142,466			45,380			46,982
Interest expense		34,957			39,875			50,992			12,920			12,177
Depreciation and amortization		123,199			128,732			131,397			32,578			35,394
Net income	$	52,995		$	221,393		$	258,966		$	83,544		$	87,813
Changes in operating assets and liabilities		143,813			40,134			76,898			(52,583	)		18,374
Equity in income of joint ventures		(3,818	)		(2,212	)		(427	)		(485	)		702
Deferred income taxes		31,207			14,153			14,114			7,416			791
Impairment of long-lived assets		—			—			1,975			—			—
Loss from disposition of fixed assets		2,711			581			1,375			44			481
Gain on involuntary conversion of assets		(455	)		—			—			—			—
Amortization of debt issue costs		1,461			2,154			1,683			438			400
Stock-based compensation expense		5,638			6,164			6,391			1,503			1,651
Provision for doubtful accounts		1,970			917			1,321			783			(155	)
Cash flow from operating activities	$	235,522		$	283,284		$	362,296		$	40,660		$	110,057

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RISK FACTORS

You should carefully consider each of the following risks, the risks discussed under the caption “Risk Factors” in the accompanying prospectus and all of the information set forth or incorporated by reference in this prospectus supplement and the accompanying prospectus, including the risks described in our Annual Report on Form 10-K for the fiscal year ended December 31, 2011 in “Item 1. Business — Risk Factors” and any other documents we file with the SEC that are incorporated by reference in this prospectus supplement and the accompanying prospectus, before investing in the notes.

A holder’s right to receive payments on the notes is effectively subordinated to the rights of our existing and future secured creditors. Further, the guarantees of the notes by the Guarantors are effectively subordinated to the Guarantors’ existing and future secured indebtedness.

Holders of our secured indebtedness and the secured indebtedness of the Guarantors will have claims that are prior to the claims of holders of the notes to the extent of the value of the assets securing that other indebtedness. Notably, we and certain of our subsidiaries, including the Guarantors, are parties to a senior secured credit facility, which is generally secured by liens on all of our cash and cash equivalents, inventory, account receivables, instruments, deposit accounts, documents and general intangibles. The notes will be effectively subordinated to that secured indebtedness. In the event of any distribution or payment of our assets in any foreclosure, dissolution, winding-up, liquidation, reorganization or other bankruptcy proceeding, holders of secured indebtedness will have prior claim to our assets that constitute their collateral. Holders of the notes will participate ratably with all holders of our senior unsecured indebtedness, and potentially with all of our other general creditors, based upon the respective amounts owed to each holder or creditor, in our remaining assets. We may apply proceeds of certain asset sales to reduce our secured indebtedness or other secured obligations, but such application will not permanently reduce our ability to incur secured indebtedness and other secured obligations under the indenture in the future. In any of the foregoing events, we cannot assure you that there will be sufficient assets to pay amounts due on the notes. As a result, holders of the notes may receive less, ratably, than holders of secured indebtedness.

Our holding company structure may affect our ability to make payments on the notes. Holders of notes may be structurally subordinated to the creditors of our non-guarantor subsidiaries.

We currently conduct our operations through subsidiaries, and our operating income and cash flow are generated by our subsidiaries. As a result, cash we obtain from our subsidiaries is the principal source of funds necessary to meet our debt service obligations. Contractual provisions or laws, as well as our subsidiaries’ financial condition and operating requirements, may limit our ability to obtain cash from our subsidiaries that we require to pay our debt service obligations, including payments on the notes. In addition, not all of our subsidiaries will guarantee the notes, and holders of the notes will have a junior position to the claims of creditors, including trade creditors and tort claimants, of our subsidiaries to the extent that such subsidiaries do not guarantee the notes. In the event of a bankruptcy, liquidation or reorganization of any of our non-guarantor subsidiaries, holders of that subsidiary’s indebtedness and its trade creditors will generally be entitled to payment of their claims from the assets of the subsidiary before any assets are made available for distribution to us. Assuming we had completed this offering and applied the proceeds from the offering as described under “Use of Proceeds” on March 31, 2012, the notes would have been effectively subordinated to $0.7 million of indebtedness and $14.1 million of other liabilities of the non-guarantor subsidiaries. The non-guarantor subsidiaries generated approximately 1.2% of our consolidated net sales for the year ended December 31, 2011 and held approximately 2.7% of our consolidated assets as of March 31, 2012.

Federal and state statutes allow courts, under specific circumstances, to void guarantees and require holders of notes to return payments received from guarantors.

Under the federal bankruptcy law and comparable provisions of state fraudulent transfer laws, a guarantee could be voided or claims in respect of a guarantee could be subordinated to all other debts of the

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applicable guarantor if, among other things, the guarantor, at the time it incurred the indebtedness evidenced by its guarantee, received less than reasonably equivalent value or fair consideration for the incurrence of such guarantee and either:

• was insolvent or rendered insolvent by reason of such incurrence; or

• was engaged or about to engage in a business or transaction for which the guarantor’s remaining assets constituted unreasonably small capital; or

• intended to incur, or believed that it would incur, debts beyond its ability to pay such debts as they mature.

As of March 31, 2012, the total liabilities of the subsidiary guarantors was approximately $696.2 million.

In addition, any payment by that guarantor pursuant to its guarantee could be voided and required to be returned to the guarantor or to a fund for the benefit of the creditors of the guarantor.

The measures of insolvency for purposes of these fraudulent transfer laws will vary depending upon the law applied in any proceeding to determine whether a fraudulent transfer has occurred. Generally, a guarantor would be considered insolvent if, at the relevant time, the sum of its debts and other liabilities, including contingent liabilities, was greater than the sum of its assets at a fair valuation, and a guarantor that was generally not then paying its debts as they became due would be presumed to be insolvent.

We may not be able to repurchase the notes upon a Change of Control Triggering Event.

If a Change of Control Triggering Event occurs, unless we have exercised our right to redeem the notes, we will be required to make an offer to repurchase the notes in cash at a price equal to 101% of their principal amount, plus accrued and unpaid interest to the date of repurchase. However, we may not be able to repurchase the notes upon a Change of Control Triggering Event because we may not have sufficient funds to do so. We may also be required to offer to repurchase certain of our other debt upon a change of control and such event may give rise to an event of default under our revolving credit facility. In addition, agreements governing indebtedness incurred in the future may restrict us from repurchasing the notes in the event of a Change of Control Triggering Event. Any failure to repurchase properly tendered notes would constitute an event of default under the indenture governing the notes, which could, in turn, cause an acceleration of our other indebtedness. See “Description of the Notes—Change of Control Triggering Event.”

Changes in our credit ratings may adversely affect the value of the notes.

We cannot provide assurance as to the credit ratings that may be assigned to the notes or that any such credit ratings will remain in effect for any given period of time or that any such ratings will not be lowered, suspended or withdrawn entirely by the rating agencies, if, in each rating agency’s judgment, circumstances warrant such an action. Further, any such ratings will be limited in scope and will not address all material risks relating to an investment in the notes, but rather will reflect only the view of each rating agency at the time the rating is issued. An explanation of the significance of such rating may be obtained from such rating agency. Actual or anticipated changes or downgrades in our credit ratings, including any announcement that our ratings are under further review for a downgrade, could adversely affect the market value of the notes and increase our corporate borrowing costs.

There is no trading market for the notes and there may never be one.

The notes will be new securities for which there is no trading market. The underwriters have informed us that they currently intend to make a market in the notes. They are not obligated to do so, however, and any such market making may be discontinued by them at any time without notice. If the notes are traded after their

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original issuance, they may trade at a discount from their public offering price, depending on prevailing interest rates, the market for similar securities, our performance and other factors. To the extent that an active trading market for the notes does not develop, the liquidity and trading prices of the notes may be harmed. We do not currently intend to apply to list the notes on any securities exchange or public market or include the notes in any quotation system.

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USE OF PROCEEDS

The net proceeds from the sale of the notes, after deducting underwriting discounts and commissions and fees and expenses related to the offering, are expected to be approximately $             million. We intend to use the net proceeds from the offering, together with cash on hand, to redeem the $250 million aggregate principal amount outstanding of our 6 ⁵/8% Senior Notes due 2016 that we have called for redemption on July 30, 2012 and to pay a premium of approximately $5.5 million in connection with such redemption, plus accrued and unpaid interest.

Pending the uses described above, we may use the net proceeds from this offering to make short-term investments.

RATIO OF EARNINGS TO FIXED CHARGES

We have presented in the table below our historical consolidated ratio of earnings to fixed charges for the periods shown.

	Years Ended December 31,											For the Three Months Ended March 31, 2012
	2011		2010		2009		2008			2007
Ratio of earnings to fixed charges		7.1x		7.2x		2.5x		—	(1)		5.5x		9.3x

(1) Earnings for 2008 were insufficient to cover fixed charges by $61.8 million.

We have computed the ratios of earnings to fixed charges by dividing earnings by fixed charges. For this purpose, “earnings” consist of earnings before income taxes plus fixed charges and equity distributions less net capitalized interest and equity investment income. “Fixed charges” consist of interest expense, capitalized interest and that portion of operating lease rental expense (one-third) we have deemed to represent the interest factor of such expense.

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CAPITALIZATION

The following table sets forth our cash and cash equivalents, short-term debt and total capitalization as of March 31, 2012 on an actual basis, and as adjusted to give effect to the issuance of the notes and the application of the net proceeds from this offering and cash on hand as described under “Use of Proceeds.” You should read this table in conjunction with “Summary—Summary Consolidated Financial, Operating and Industry Data” appearing elsewhere in this prospectus supplement, and the sections entitled “Management’s Discussion and Analysis of Financial Conditions and Results of Operations” included in our Annual Report on Form 10-K for the fiscal year ended December 31, 2011 and in our Quarterly Report on Form 10-Q for the quarter ended March 31, 2012, and our consolidated financial statements and related notes, which are incorporated by reference in this prospectus supplement and the accompanying prospectus.

	March 31, 2012
	Actual		As Adjusted
	(dollars in millions)
Cash and cash equivalents	$	895.1	$	889.9
Short-term debt	$	—	$	—
Long-term debt, including current portion:
Senior secured revolving credit facility (1)	$	—	$	—
6 5/8% Senior Notes due 2016		249.7		—
Variable rate loan due 2027 (related to tax-exempt revenue bonds)		10.9		10.9
6 1/2% Senior Notes due 2029 (related to tax-exempt GO Zone bonds)		100.0		100.0
6  3/4% Senior Notes due 2032 (related to tax-exempt GO Zone bonds)		250.0		250.0
6 1/2% Senior Notes due 2035 (related to tax-exempt GO Zone bonds)		89.0		89.0
6 1/2% Senior Notes due 2035 (related to tax-exempt IKE Zone bonds)		65.0		65.0
Senior Notes due 2022 offered hereby		—		250.0
Total long-term debt, including current portion		764.6		764.9
Stockholders’ equity		1,863.0		1,858.7
Total capitalization	$	2,627.6	$	2,623.6

(1) There have been no borrowings outstanding under the revolving credit facility since the fourth quarter of 2008.

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DESCRIPTION OF THE NOTES

The following description is a summary of the material provisions of the indenture governing the notes and does not purport to be complete and is subject to, and is qualified in its entirety by reference to, all the provisions of the indenture. Copies of the indenture are available as set forth below under “Where You Can Find More Information.” Certain defined terms used in this description but not defined below have the meanings assigned to them in the indenture. In this description, the words “Westlake,” “we,” “us” and “our” refer only to Westlake Chemical Corporation and not to any of its subsidiaries.

General

Westlake will issue the notes under an indenture among itself, the Guarantors and The Bank of New York Mellon Trust Company, N.A. (as successor to JPMorgan Chase Bank, National Association), as 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 notes are a separate series of “senior debt securities” described in the accompanying prospectus, and this summary supplements that description.

The indenture does not limit the amount of debt securities that may be issued under the indenture. As of March 31, 2012, $753.7 million of debt securities were outstanding under the indenture. We intend to use the net proceeds from the offering of the notes to redeem on July 30, 2012 the $250 million aggregate principal amount outstanding of our 6 ⁵/8% Senior Notes due 2016. We may issue additional debt securities under the indenture from time to time in one or more series. We may from time to time, without giving notice to or seeking the consent of the holders of the notes offered hereby, issue debt securities having the same terms (except for the issue date, and, in some cases, the public offering price and, to the extent applicable, the first date of interest accrual and the first interest payment date) as, and ranking equally and ratably with, the notes offered hereby. Any additional debt securities having such similar terms, together with the notes offered hereby, will constitute a single series of securities under the indenture, including for purposes of voting. No such additional debt securities may be issued if an “event of default” (as such term is defined in the accompanying prospectus) has occurred and is continuing with respect to the notes offered hereby.

The registered holder of a note will be treated as the owner of the note for all purposes. Only registered holders will have rights under the indenture.

Principal, Maturity and Interest

Westlake will issue $250.0 million in aggregate principal amount of notes in this offering. The notes will mature on                     , 2022. Interest on the notes will accrue at the rate of     % per annum and will be payable semi-annually in arrears on             and             , commencing on                     , 2013. Westlake will make each interest payment to the holders of record on the immediately preceding             and             (whether or not a business day).

Interest on the notes will accrue from the date of original issuance or, if interest has already been paid or duly provided for, from the date it was most recently paid or duly provided for. Interest will be computed on the basis of a 360-day year of twelve 30-day months. 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. For these purposes, a “business day” is any day that is not a Saturday, a Sunday or a day on which banking institutions in any of New York, New York or Houston, Texas is authorized or obligated by law, regulation or executive order to remain closed.

The notes will be issued in denominations of $2,000 and integral multiples of $1,000 in excess thereof in book-entry form only. See “—Book-Entry, Clearance and Settlement.”

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Guarantees

Westlake’s payment obligations under the notes will be guaranteed by each of Westlake’s current and future Domestic Subsidiaries which guarantees any other Debt of Westlake or any other Guarantor in excess of $5 million. These guarantees will be joint and several obligations of the Guarantors. The obligations of each Guarantor under its guarantee will be limited as necessary to prevent that Guarantee from constituting a fraudulent transfer or conveyance under applicable law. See “Risk Factors—Federal and state statutes allow courts, under specific circumstances, to void guarantees and require holders of notes to return payments received from guarantors.”

The Guarantee of a Guarantor will be released:

• in connection with any sale or other disposition of all or substantially all of the assets of that Guarantor (including by way of merger or consolidation) to a Person that is not (either before or after giving effect to such transaction) Westlake or a Subsidiary of Westlake;

• in connection with any sale or other disposition of all of the Capital Stock of a Guarantor to a Person that is not (either before or after giving effect to such transaction) Westlake or a Subsidiary of Westlake;

• upon legal defeasance or satisfaction and discharge of the notes as provided in the accompanying prospectus under the captions “Description of Debt Securities—Defeasance and Discharge;” or

• at such time as such Guarantor ceases to guarantee any other Debt of Westlake or a Guarantor in excess of $5 million.

Ranking

The notes and the guarantees will be senior unsecured obligations of Westlake and each of the Guarantors, respectively, and will rank equally in right of payment with all existing and future unsecured and unsubordinated obligations of Westlake and such Guarantor, respectively. As of March 31, 2012, we had an aggregate of $764.6 million of unsecured and unsubordinated indebtedness, consisting of senior notes and a $10.9 million loan from the proceeds of tax-exempt waste disposal revenue bonds. We intend to use the net proceeds from the offering of the notes to redeem on July 30, 2012 the $250 million aggregate principal amount outstanding of our 6 ⁵/8% Senior Notes due 2016.

The notes and the guarantees will effectively rank junior to all existing and future secured indebtedness of Westlake and the Guarantors, respectively, to the extent of the value of the assets securing such indebtedness. As of March 31, 2012, neither Westlake nor any of Guarantors had any secured indebtedness. However, Westlake and certain of its Subsidiaries, including the Guarantors, are parties to a senior secured revolving credit facility, which is generally secured by liens on Westlake’s and such Subsidiaries’ cash and cash equivalents, inventory, accounts receivables, instruments, deposit accounts, documents and general intangibles. The notes will be effectively subordinated to that secured indebtedness. As of March 31, 2012, Westlake had no outstanding borrowings and outstanding letters of credit totaling $15.7 million under the revolving credit facility. In the event of any distribution or payment of Westlake’s or its Subsidiaries’ assets in any foreclosure, dissolution, winding-up, liquidation, reorganization or other bankruptcy proceeding, holders of secured indebtedness will have prior claim to such assets that constitute their collateral. Holders of the notes will participate ratably with all holders of our senior unsecured indebtedness, and potentially with all of our other general creditors, based upon the respective amounts owed to each holder or creditor, in our remaining assets. See “Risk Factors—A holder’s right to receive payments on the notes is effectively subordinated to the rights of our existing and future secured creditors. Further, the guarantees of the notes by the Guarantors are effectively subordinated to the Guarantors’ existing and future secured indebtedness.”

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In addition, not all of our subsidiaries will guarantee the notes. In the event of a bankruptcy, liquidation or reorganization of any of these non-guarantor subsidiaries, that non-guarantor subsidiary will pay the holders of its debt and its trade creditors before it will be able to distribute any of its assets to us. Accordingly, the notes will be effectively subordinated to creditors, including trade creditors, if any, of our non-guarantor subsidiaries. The non-guarantor subsidiaries generated approximately 1.2% of our consolidated net sales for the year ended December 31, 2011 and held approximately 2.7% of our consolidated assets as of March 31, 2012. As of March 31, 2012, the total liabilities of our non-guarantor subsidiaries was approximately $14.8 million, including trade payables, and the total assets of such subsidiaries was approximately $90.3 million.

Optional Redemption

The notes will be redeemable at our option, in whole or in part, at any time and from time to time prior to                     , 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:

• 100% of the principal amount of the notes to be redeemed; and

• 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      basis points,

plus, in each case, accrued and unpaid interest to the redemption date.

In addition, at any time on or after                     , 2022 (three months prior to the maturity date of the notes), the notes will be redeemable at our option, in whole or in part, 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.

“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.

“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.

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

“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 us. If, however, any of them shall cease to be a primary U.S. Government securities dealer, we will substitute another nationally recognized investment banking firm that is such a dealer.

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“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.

“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.

We will 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.

If we elect to redeem less than all of the notes, and such notes are at the time represented by a global note, then the depositary will select by lot the particular notes to be redeemed. If we elect to redeem less than all of the notes, and any of such notes are not represented by a global note, then the trustee will select the particular notes to be redeemed in a manner it deems fair and appropriate (and the depositary will select by lot the particular interests in any global note to be redeemed). Unless there is a default in payment of the redemption price, on and after the redemption date, interest will cease to accrue on the notes or portions thereof called for redemption.

We 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.

Sinking Fund

The notes will not be entitled to any sinking fund.

Change of Control Triggering Event

Upon the occurrence of a Change of Control Triggering Event, unless we have exercised our right to redeem the notes as described under “—Optional Redemption” in accordance with the indenture, each holder of the notes will have the right to require us 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 of the notes 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.

Within 30 days following the date upon which the Change of Control Triggering Event occurred, or at our option, prior to any Change of Control but after the public announcement of the pending Change of Control, we 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 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, will 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.

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On the Change of Control Payment Date, we will, to the extent lawful:

• 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;

• 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

• 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 us of notes pursuant to the Change of Control Offer have been complied with.

We 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 us 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.

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.

We 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 the Change of Control Offer provisions of the notes, we will comply with those securities laws and regulations and will not be deemed to have breached our obligations under the Change of Control Offer provisions of the notes by virtue of any such conflict.

For purposes of the foregoing discussion of a Change of Control Offer, the following definitions are applicable:

“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 us 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) if each Rating Agency making the reduction in rating does not publicly announce or confirm or inform the trustee in writing at our 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 we have not selected a replacement Rating Agency pursuant to the terms of the indenture, the rating of such Rating Agency shall be deemed to be below an Investment Grade Rating on such day.

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“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.

“Change of Control” means the occurrence of any of the following after the date of issuance of the notes:

• 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 Westlake and its 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 Westlake or one of its Subsidiaries;

• 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 Westlake or any of its Subsidiaries 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 our Voting Stock representing more than 50% of the voting power of our outstanding Voting Stock;

• we consolidate with, or merge with or into, any Person, or any Person consolidates with, or merges with or into, us, in any such event pursuant to a transaction in which any of our outstanding Voting Stock or Voting Stock of such other Person is converted into or exchanged for cash, securities or other property, other than any such transaction where our Voting Stock 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;

• during any period of 24 consecutive calendar months, the majority of the members of our board of directors shall no longer be composed of individuals (a) who were members of our board of directors on the first day of such period or (b) whose election or nomination to our board of directors was approved by individuals referred to in clause (a) above constituting, at the time of such election or nomination, at least a majority of our board of directors or, if directors are nominated by a committee of our board of directors, constituting at the time of such nomination, at least a majority of such committee; or

• the adoption of a plan relating to our liquidation or dissolution.

Notwithstanding the foregoing, a transaction will not be deemed to involve a Change of Control if (i) we become 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 our Voting Stock immediately prior to that transaction.

“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.

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“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 us under the circumstances permitting us to select a replacement rating agency and in the manner 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.

“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, we may appoint another “nationally recognized statistical rating organization” (as defined under the Exchange Act) as a replacement for such Rating Agency; provided, that we shall give written notice of such appointment to the trustee.

“S&P” means Standard & Poor’s Ratings Services, a division of The McGraw-Hill Companies, Inc., and its successors.

“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.

For purposes of the notes, “Person” includes any individual, corporation, limited liability company, partnership, joint venture, association, joint stock company, trust, estate, unincorporated organization or government or any agency or political subdivision thereof or any other entity.

The definition of Change of Control includes a phrase relating to the direct or indirect sale, lease, transfer, conveyance or other disposition of “all or substantially all” of the properties or assets of Westlake and its Subsidiaries taken as a whole. Although there is a limited body of case law interpreting the phrase “substantially all,” there is no precise, established definition of the phrase under applicable law. Accordingly, the applicability of the requirement that we offer to repurchase the notes as a result of a sale, lease, transfer, conveyance or other disposition of less than all of the assets of Westlake and its Subsidiaries taken as a whole to another Person or group may be uncertain.

Certain Covenants

The indenture will contain, among others, the following covenants:

Restrictions on Secured Debt

Under the indenture, Westlake will not, and we will not permit any Restricted Subsidiary (as defined below) 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 (as defined below) of Westlake or any Restricted Subsidiary, or any shares of 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 we shall so determine, any other indebtedness of Westlake 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 Westlake and its Restricted Subsidiaries in respect of any Sale and Leaseback Transaction (as defined below) would not, at the time of such incurrence,

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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:

• Mortgages on such property or shares of stock or Debt existing on the first date the notes are originally issued;

• Mortgages on such property or shares of 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 Westlake or any of its Subsidiaries or (iii) Westlake or one of its Subsidiaries 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;

• Mortgages in favor of Westlake or any Guarantor;

• 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;

• Mortgages in favor of any governmental entity to secure progress, advance or other payments pursuant to any contract or provision of any statute;

• Mortgages on such property or shares of stock or Debt existing at the time of acquisition thereof (including acquisition through merger or consolidation);

• Mortgages on such property or shares of 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;

• Mortgages incurred in connection with a Sale and Leaseback Transaction satisfying the provisions described under “—Limitations on Sale and Leaseback Transactions” below; and

• 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 bullet points; provided that such extension, renewal or replacement Mortgage shall be limited to all or a part of the same such property or shares of stock or Debt that secured the Mortgage extended, renewed or replaced (plus improvements on such property).

Limitations on Sale and Leaseback Transactions

Under the indenture, Westlake will not, and will not permit any Restricted Subsidiary to, enter into any arrangement with any bank, insurance company or other lender or investor (not including us or any Restricted Subsidiary) or to which any such lender or investor is a party, providing for the leasing by us 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

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commencement of full operation thereof, by us 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:

• such Sale and Leaseback Transaction is with a governmental entity that provides financial or tax benefits;

• we or such Restricted Subsidiary could create Secured Debt pursuant to the provisions described under “—Restrictions on Secured Debt” 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 notes issued under the indenture; or

• 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 (b) within 180 days after such sale or transfer shall have been made by us or by a Restricted Subsidiary, we 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 (as defined below) of Westlake; provided that the amount to be applied to the retirement of Funded Debt of Westlake shall be reduced by (x) the principal amount of notes issued under the indenture 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 issued under the indenture, voluntarily retired by us within 180 days after such sale. No retirement referred to in this clause (3) may be effected by payment at maturity or pursuant to any mandatory sinking fund payment or mandatory prepayment provision.

Limitations on Consolidations, Mergers and Sales of Assets

The indenture will provide that we may not consolidate with or merge into any entity or sell, lease, convey, assign, transfer or dispose of all or substantially all of our assets to any entity unless:

(1) the resulting, surviving or transferee Person is either Westlake or is a corporation organized under the laws of the United States, any state thereof, or the District of Columbia, and, if not Westlake, the resulting entity assumes by a supplemental indenture the due and punctual payments on the notes and the performance of our covenants and obligations under the indenture; and

(2) immediately after giving effect to the transaction, no default or event of default under the indenture has occurred and is continuing or would result from the transaction.

Upon any transaction of the type described above, the resulting entity will succeed to and be substituted for and may exercise all of our rights and powers under the indenture and the notes with the same effect as if the resulting entity had been named as us in the indenture. In the case of any asset transfer or disposition other than a lease, when the resulting entity assumes all of our obligations and covenants under the indenture and the notes, we will be relieved of all such obligations.

Certain Definitions

“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

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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 we elect 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.

“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 Westlake and its consolidated Subsidiaries and computed in accordance with generally accepted accounting principles in the United States as in effect from time to time. Deferred income taxes, deferred investment tax credit or other similar items, as calculated in accordance with generally accepted accounting principles in the United States as in effect from time to time, will not be considered as a liability or as a deduction from or adjustment to total assets.

“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 Westlake 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.

“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 Westlake 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, as evidenced by a Board Resolution, is not of material importance to the total business conducted by Westlake and its Subsidiaries taken as a whole. As of March 31, 2012, Westlake and its Restricted Subsidiaries had Principal Properties representing approximately 29% of Westlake’s consolidated assets as of such date.

“Restricted Subsidiary” means a wholly-owned Subsidiary of Westlake 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.

“Subsidiary” means a Person more than 50% of the outstanding Voting Stock (as defined above) of which is owned, directly or indirectly, by Westlake or by one or more other Subsidiaries, or by Westlake and one or more other Subsidiaries.

Book-Entry, Clearance and Settlement

The notes will be issued in the form of one or more fully registered global notes (each a “global note”) which will be deposited with, or on behalf of, The Depository Trust Company, New York, New York (the “Depositary”) and registered in the name of Cede & Co., the Depositary’s nominee. We will not issue notes in

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certificated form except in certain circumstances. Beneficial interests in the global notes will be represented through book-entry accounts of financial institutions acting on behalf of beneficial owners as direct and indirect participants in the Depositary (the “Depositary Participants”). Investors may elect to hold interests in the global notes through either the Depositary (in the United States), or Clearstream Banking Luxembourg S.A. (“Clearstream Luxembourg”) or Euroclear Bank S.A./N.V., as operator of the Euroclear System (“Euroclear”) (in Europe) if they are participants in those systems, or indirectly through organizations that are participants in those systems. Clearstream Luxembourg and Euroclear will hold interests on behalf of their participants through customers’ securities accounts in Clearstream Luxembourg’s and Euroclear’s names on the books of their respective depositaries, which in turn will hold such interests in customers’ securities accounts in the depositaries’ names on the books of the Depositary. At the present time, Citibank, N.A. acts as U.S. depositary for Clearstream Luxembourg and JPMorgan Chase Bank acts as U.S. depositary for Euroclear (the “U.S. Depositaries”). Beneficial interests in the global notes will be held in minimum denominations of $2,000 and integral multiples of $1,000 in excess thereof. Except as set forth below, the global notes may be transferred, in whole but not in part, only to another nominee of the Depositary or to a successor of the Depositary or its nominee.

The Depositary has advised us that it is a limited-purpose trust company organized under the New York Banking Law, a “banking organization” within the meaning of the New York Banking Law, a member of the Federal Reserve System, a “clearing corporation” within the meaning of the New York Uniform Commercial Code, and a “clearing agency” registered pursuant to the provisions of Section 17A of the Exchange Act. The Depositary holds securities that its participants (“Direct Participants”) deposit with the Depositary. The Depositary also facilitates the settlement among Direct Participants of securities transactions, such as transfers and pledges, in deposited securities through electronic computerized book-entry changes in Direct Participants’ accounts, thereby eliminating the need for physical movement of securities certificates. Direct Participants include securities brokers and dealers (which may include the underwriters), banks, trust companies, clearing corporations and certain other organizations. The Depositary is owned by a number of its Direct Participants and by NYSE Euronext and the Financial Industry Regulatory Authority, Inc. Access to the Depositary’s book-entry system is also available to others such as securities brokers and dealers, banks and trust companies that clear through or maintain a custodial relationship with a Direct Participant, either directly or indirectly (“Indirect Participants”). The rules applicable to the Depositary and its Direct and Indirect Participants are on file with the SEC.

Clearstream Luxembourg has advised us that it is incorporated under the laws of Luxembourg as a professional depositary. Clearstream Luxembourg holds securities for its participating organizations, known as Clearstream Luxembourg participants, and facilitates the clearance and settlement of securities transactions between Clearstream Luxembourg participants through electronic book-entry changes in accounts of Clearstream Luxembourg participants, thereby eliminating the need for physical movement of certificates. Clearstream Luxembourg provides to Clearstream Luxembourg participants, among other things, services for safekeeping, administration, clearance and settlement of internationally traded securities and securities lending and borrowing. Clearstream Luxembourg interfaces with domestic markets in several countries. As a professional depositary, Clearstream Luxembourg is subject to regulation by the Luxembourg Commission for the Supervision of the Financial Sector, also known as the Commission de Surveillance du Secteur Financier. Clearstream Luxembourg participants are recognized financial institutions around the world, including underwriters, securities brokers and dealers, banks, trust companies, clearing corporations and certain other organizations. Indirect access to Clearstream Luxembourg is also available to others, such as banks, brokers, dealers and trust companies that clear through, or maintain a custodial relationship with, a Clearstream Luxembourg participant either directly or indirectly.

Distributions with respect to the notes held beneficially through Clearstream Luxembourg will be credited to the cash accounts of Clearstream Luxembourg participants in accordance with its rules and procedures, to the extent received by the U.S. Depositary for Clearstream Luxembourg.

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Euroclear has advised us that it was created in 1968 to hold securities for its participants, known as Euroclear participants, and to clear and settle transactions between Euroclear participants and between Euroclear participants and participants of certain other securities intermediaries through simultaneous electronic book-entry delivery against payment, eliminating the need for physical movement of certificates and any risk from lack of simultaneous transfers of securities and cash. Euroclear is owned by Euroclear Clearance System Public Limited Company and operated through a license agreement by Euroclear Bank S.A./N.V., known as the Euroclear operator. The Euroclear operator provides Euroclear participants, among other things, with safekeeping, administration, clearance and settlement, securities lending and borrowing and related services. Euroclear participants include banks (including central banks), securities brokers and dealers and other professional financial intermediaries and may include the underwriters.

Indirect access to Euroclear is also available to others that clear through or maintain a custodial relationship with a Euroclear participant, either directly or indirectly.

The Euroclear operator is regulated and examined by the Belgian Banking and Finance Commission.

Securities clearance accounts and cash accounts with the Euroclear operator are governed by the Terms and Conditions Governing Use of Euroclear and the related Operating Procedures of the Euroclear System, and applicable Belgian law, collectively referred to as the terms and conditions. The terms and conditions govern transfers of securities and cash within Euroclear, withdrawals of securities and cash from Euroclear, and receipts of payments with respect to securities in Euroclear. All securities in Euroclear are held on a fungible basis without attribution of specific certificates to specific securities clearance accounts. The Euroclear operator acts under the terms and conditions only on behalf of Euroclear participants, and has no record of or relationship with persons holding through Euroclear participants.

Distributions with respect to notes held beneficially through Euroclear will be credited to the cash accounts of Euroclear participants in accordance with the terms and conditions, to the extent received by the U.S. Depositary for Euroclear.

If the Depositary is at any time unwilling or unable to continue as depositary and a successor depositary is not appointed by us within 90 days, we will issue the notes in definitive form in exchange for the entire global note representing such notes. In addition, we may at any time, and in our sole discretion and subject to the procedures of the Depositary, determine not to have the notes represented by the global note and, in such event, will issue notes in definitive form in exchange for the global note representing such notes. In any such instance, an owner of a beneficial interest in the global note will be entitled to physical delivery in definitive form of notes represented by such global note equal in principal amount to such beneficial interest and to have such notes registered in its name.

Title to book-entry interests in the notes will pass by book-entry registration of the transfer within the records of Clearstream Luxembourg, Euroclear or the Depositary, as the case may be, in accordance with their respective procedures. Book-entry interests in the notes may be transferred within Clearstream Luxembourg and within Euroclear and between Clearstream Luxembourg and Euroclear in accordance with procedures established for these purposes by Clearstream Luxembourg and Euroclear. Book-entry interests in the notes may be transferred within the Depositary in accordance with procedures established for this purpose by the Depositary. Transfers of book-entry interests in the notes among Clearstream Luxembourg and Euroclear and the Depositary may be effected in accordance with procedures established for this purpose by Clearstream Luxembourg, Euroclear and the Depositary.

Global clearance and settlement procedures

Initial settlement for the notes will be made in immediately available funds. Secondary market trading between Depositary Participants will occur in the ordinary way in accordance with the Depositary’s rules and will be settled in immediately available funds using the Depositary’s Same-Day Funds Settlement System.

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Secondary market trading between Clearstream Luxembourg participants and Euroclear participants will occur in the ordinary way in accordance with the applicable rules and operating procedures of Clearstream Luxembourg and Euroclear and will be settled using the procedures applicable to conventional eurobonds in immediately available funds.

Cross-market transfers between persons holding directly or indirectly through the Depositary, on the one hand, and directly or indirectly through Clearstream Luxembourg or Euroclear participants, on the other, will be effected through the Depositary in accordance with the Depositary’s rules on behalf of the relevant European international clearing system by its U.S. Depositary; however, such cross-market transactions will require delivery of instructions to the relevant European international clearing system by the counterparty in such system in accordance with its rules and procedures and within its established deadlines (European time).

The relevant European international clearing system will, if the transaction meets its settlement requirements, deliver instructions to its U.S. Depositary to take action to effect final settlement on its behalf by delivering or receiving the notes in the Depositary, and making or receiving payment in accordance with normal procedures for same-day funds settlement applicable to the Depositary. Clearstream Luxembourg participants and Euroclear participants may not deliver instructions directly to their respective U.S. Depositaries.

Because of time-zone differences, credits of the notes received in Clearstream Luxembourg or Euroclear as a result of a transaction with a Depositary Participant will be made during subsequent securities settlement processing and dated the business day following the Depositary settlement date. Such credits, or any transactions in the notes settled during such processing, will be reported to the relevant Euroclear participants or Clearstream Luxembourg participants on that business day. Cash received in Clearstream Luxembourg or Euroclear as a result of sales of notes by or through a Clearstream Luxembourg participant or a Euroclear participant to a Depositary Participant will be received with value on the business day of settlement in the Depositary but will be available in the relevant Clearstream Luxembourg or Euroclear cash account only as of the business day following settlement in the Depositary.

Although the Depositary, Clearstream Luxembourg and Euroclear have agreed to the foregoing procedures in order to facilitate transfers of the notes among participants of the Depositary, Clearstream Luxembourg and Euroclear, they are under no obligation to perform or continue to perform such procedures and such procedures may be changed or discontinued at any time.

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MATERIAL U.S. FEDERAL TAX CONSEQUENCES

The following discussion is a summary of certain U.S. federal income and, in the case of certain non-U.S. holders (as defined below), estate tax consequences of the acquisition, ownership and disposition of the notes. This discussion is based upon the provisions of the Internal Revenue Code of 1986, as amended (the “Code”), applicable U.S. Treasury Regulations promulgated thereunder, judicial authorities and administrative interpretations, in each case as of the date of this prospectus supplement, all of which are subject to change, possibly with retroactive effect, and are subject to different interpretations. We cannot assure you that the U.S. Internal Revenue Service (the “IRS”) will not challenge one or more of the tax consequences described in this discussion, and we have not obtained, nor do we intend to obtain, a ruling from the IRS or an opinion of counsel with respect to the U.S. federal income tax consequences of acquiring, holding or disposing of the notes.

This discussion does not purport to address all tax consequences that may be relevant to a holder in light of the holder’s particular circumstances or status, nor does it discuss the U.S. federal income tax consequences to certain types of holders subject to special treatment under the U.S. federal income tax laws, such as financial institutions, insurance companies, regulated investment companies, tax-exempt organizations, dealers in securities, persons subject to alternative minimum tax, pass-through entities treated as partnerships for U.S. federal income tax purposes (or investors in such entities), U.S. holders (as defined below) whose functional currency is not the U.S. dollar, U.S. expatriates and former long-term residents of the United States, or persons that hold the notes as part of a hedge, conversion transaction, straddle or other risk reduction transaction. This discussion of U.S. federal income tax consequences is limited to those holders that purchase the notes in this offering at their “issue price” (which is the first price at which a substantial amount of the notes is sold to investors other than bond houses, brokers, or similar persons or organizations acting in the capacity of underwriters, placement agents or wholesalers) and that hold the notes as capital assets within the meaning of Section 1221 of the Code (generally, property held for investment). Moreover, this discussion does not address the tax consequences arising under any applicable state, local or foreign tax laws or the application of other U.S. federal taxes, such as the federal gift tax, the alternative minimum tax, or, except as specifically noted under “—Tax consequences to non-U.S. holders—U.S. federal estate tax,” the federal estate tax.

If any entity treated as a partnership for U.S. federal income tax purposes holds notes, the U.S. federal income tax treatment of a partner of the partnership generally will depend upon the status of the partner and the activities of the partnership. If you are a partner of a partnership acquiring the notes, you are encouraged to consult your own tax advisor about the tax consequences of acquiring, holding and disposing of the notes.

In certain circumstances (for example, see “Description of the Notes—Change of Control Triggering Event”), we may be obligated to pay amounts on the notes that are in excess of the stated interest on, or principal amount of, the notes. This may cause the notes to be subject to special rules for debt instruments with contingent payments unless, as of the issue date of the notes, the likelihood of the event that would result in such payment is “remote” or such contingency is considered “incidental.” We intend to take the position that any such contingencies should be treated as remote and/or incidental, as of the issue date of the notes, within the meaning of the applicable U.S. Treasury Regulations. Accordingly, any additional amounts, if paid, should be taxable to a U.S. holder only at the time such amounts accrue or are received in accordance with such U.S. holder’s regular method of accounting. Under applicable U.S. Treasury Regulations, our determination is binding on all holders of the notes (other than holders that properly disclose to the IRS that they are taking a different position) but is not binding on the IRS. The IRS may take a contrary position, which, if sustained, could affect the timing and character of a holder’s income with respect to the notes in a materially adverse way. The remainder of this discussion assumes that the notes are not contingent payment debt instruments.

Investors considering the purchase of notes are encouraged to consult their own tax advisors regarding the application of the U.S. federal tax laws to their particular situations and the applicability and effect of state, local or foreign tax laws and tax treaties.

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Tax Consequences to U.S. Holders

You are a “U.S. holder” for purposes of this discussion if you are a beneficial owner of a note and, for U.S. federal income tax purposes, you are:

• an individual who is a citizen or a resident of the United States;

• a corporation, or other entity taxable as a corporation for U.S. federal income tax purposes, that was created or organized in or under the laws of the United States, any state thereof or the District of Columbia;

• an estate, the income of which is subject to U.S. federal income taxation regardless of its source; or

• a trust, if (1) a U.S. court is able to exercise primary supervision over the administration of the trust and one or more U.S. persons have the authority to control all substantial decisions of the trust, or (2) such trust has a valid election in effect under applicable U.S. Treasury Regulations to be treated as a U.S. person.

Stated Interest on the Notes

Stated interest on the notes generally will be taxable to you as ordinary income at the time it is received or accrued in accordance with your regular method of accounting for U.S. federal income tax purposes.

Disposition of the Notes

You will generally recognize capital gain or loss on the sale, redemption, exchange, retirement or other taxable disposition of a note measured by the difference between (i) the amount of cash and fair market value of any other property received therefor (except to the extent such cash or property is attributable to accrued but unpaid stated interest, which will be treated as a payment of interest and will be taxable as ordinary income to the extent you have not previously included the accrued interest in income) and (ii) your adjusted tax basis in the note. Your adjusted tax basis in a note will generally equal the amount you paid for the note. Such gain or loss will be long-term capital gain or loss if you held the note for more than one year at the time of the sale, redemption, exchange, retirement or other taxable disposition. Long-term capital gains of non-corporate holders are generally eligible for reduced rates of taxation. The deductibility of capital losses is subject to limitations.

Information Reporting and Backup Withholding

Information reporting requirements may apply to payments of interest on, or the proceeds of the disposition (including a retirement or redemption) of, notes held by you. These requirements, however, do not apply with respect to certain exempt holders, such as corporations.

Backup withholding (currently at a rate of 28%) will apply to payments of interest on, or the proceeds of the disposition (including a retirement or redemption) of, the notes, unless you provide the paying agent with a taxpayer identification number, certified under penalties of perjury, as well as certain other information, or otherwise establish an exemption from backup withholding.

Backup withholding is not an additional tax. Any amounts withheld under the backup withholding rules will be allowed as a credit against your U.S. federal income tax liability and may entitle you to a refund, provided the required information is timely furnished to the IRS. The information reporting requirements may apply regardless of whether backup withholding is required.

Tax Consequences to Non-U.S. Holders

You are a “non-U.S. holder” for purposes of this discussion if you are a beneficial owner of notes that is an individual, corporation, estate or trust for U.S. federal income tax purposes, and you are not a U.S. holder.

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Interest on the Notes

Subject to the discussion below under the headings “—Information Reporting and Backup Withholding” and “—FATCA Withholding”, payments of interest on the notes generally will be exempt from withholding of U.S. federal income tax under the “portfolio interest” exemption if you properly certify as to your foreign status, as described below, and:

• you do not own, directly or indirectly, actually or constructively, 10% or more of the total combined voting power of all classes of our voting stock;

• you are not a bank whose receipt of interest on the notes is in connection with an extension of credit made pursuant to a loan agreement entered into in the ordinary course of business;

• you are not a “controlled foreign corporation” for U.S. federal income tax purposes that is related to us; and

• interest on the notes is not effectively connected with your conduct of a U.S. trade or business.

The portfolio interest exemption applies only if you appropriately certify as to your foreign status. You can generally meet this certification requirement by providing a properly executed IRS Form W-8BEN or appropriate substitute form to us or our paying agent. If you hold the notes through a financial institution or other agent acting on your behalf, you may be required to provide appropriate certifications to your agent. Your agent will then generally be required to provide appropriate certifications to us or our paying agent, either directly or through other intermediaries. Special rules apply to foreign estates and trusts, and in certain circumstances, certifications as to foreign status of trust owners or beneficiaries may have to be provided to us or our paying agent. In addition, special rules apply to qualified intermediaries that enter into withholding agreements with the IRS.

If you cannot satisfy the requirements described above, payments of interest made to you will be subject to U.S. federal withholding tax, currently at a 30% rate, unless you provide us or our paying agent with a properly executed IRS Form W-8BEN (or successor form) claiming an exemption from (or a reduction of) withholding under an applicable income tax treaty, or the payments of interest are effectively connected with your conduct of a trade or business in the United States and you meet the certification requirements described below (see “—Income or Gain Effectively Connected with a U.S. Trade or Business”).

Disposition of Notes

Subject to the discussion below under the headings “—Information Reporting and Backup Withholding” and “—FATCA Withholding,” you generally will not be subject to U.S. federal income tax on any gain realized on the sale, redemption, exchange, retirement or other taxable disposition of a note unless:

• the gain is effectively connected with the conduct by you of a U.S. trade or business; or

• you are an individual who has been present in the United States for 183 days or more in the taxable year of disposition and certain other requirements are met.

If you are a non-U.S. holder described in the first bullet point above, you generally will be subject to U.S. federal income tax as described below (see “—Income or Gain Effectively Connected with a U.S. Trade or Business”). If you are a non-U.S. holder described in the second bullet point above, you generally will be subject to U.S. federal income tax, currently at a 30% rate (or lower applicable treaty rate), on the gain derived from the sale, redemption, exchange, retirement or other taxable disposition, which may be offset by U.S. source capital losses.

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Income or Gain Effectively Connected with a U.S. Trade or Business

If any interest on the notes or gain from the sale, redemption, exchange, retirement or other taxable disposition of the notes is effectively connected with a U.S. trade or business conducted by you (and, if an applicable income tax treaty so requires, is attributable to your permanent establishment in the United States), then you will generally be subject to U.S. federal income tax in the same manner as a U.S. holder. If interest received with respect to the notes is effectively connected income (whether or not a treaty applies), the withholding tax (currently at a 30% rate) described above will not apply (assuming an appropriate certification is provided). You can generally meet the certification requirements by providing a properly executed IRS Form W-8ECI or appropriate substitute form to us or our paying agent. If you are a corporation for U.S. federal income tax purposes, that portion of your earnings and profits that is effectively connected with your U.S. trade or business also may be subject to a “branch profits tax,” currently at a 30% rate, although an applicable income tax treaty may provide for a lower rate.

Information Reporting and Backup Withholding

Payments to you of interest on a note, and amounts withheld from such payments, if any, generally will be required to be reported to the IRS and to you. Backup withholding (currently at a rate of 28%) generally will not apply to payments of interest on a note to a non-U.S. holder if the statement described in “—Interest on the Notes” above is provided by the holder, or the holder otherwise establishes an exemption, provided that we do not have actual knowledge or reason to know that the holder is a U.S. person.

Payment of the proceeds of a disposition (including a retirement or redemption) of a note effected by the U.S. office of a U.S. or foreign broker will be subject to information reporting requirements and backup withholding unless you properly certify, under penalties of perjury, as to your foreign status and certain other conditions are met, or you otherwise establish an exemption. Information reporting and backup withholding generally will not apply to any payment of the proceeds of the disposition of a note effected outside the United States by a foreign office of a broker; however, if such broker has certain connections to the United States, then information reporting, but not backup withholding, will apply unless the broker has documentary evidence in its records that you are a non-U.S. holder and certain other conditions are met, or you otherwise establish an exemption.

Backup withholding is not an additional tax. Any amounts withheld under the backup withholding rules will be allowed as a credit against your U.S. federal income tax liability, if any, and may entitle you to a refund, provided the required information is timely furnished to the IRS. The information reporting requirements may apply regardless of whether backup withholding is required.

FATCA Withholding

The Hiring Incentives to Restore Employment Act, enacted on March 18, 2010, would impose a 30% withholding tax on any payments made to certain foreign entities of interest on the notes and the gross proceeds of the sale or other disposition of the notes, unless such foreign entities satisfy specific information reporting or other compliance provisions, or an exemption applies. Under certain circumstances, a holder might be eligible for refunds or credits of such taxes. Although this legislation currently applies to payments made after December 31, 2012, the Treasury and the IRS have issued administrative guidance indicating that they plan to issue Treasury Regulations that will delay the effective date of the withholding regime so that withholding will only apply to payments made after December 31, 2013 (in the case of interest payments) and December 31, 2014 (in the case of disposition proceeds). Proposed Treasury Regulations have been issued which, if finalized, would confirm the extension of the effective dates for withholding. Additionally, payments with respect to debt obligations that were outstanding on March 18, 2012 are not subject to these rules; however, proposed regulations not yet in effect would, if adopted, extend this grandfathering date to January 1, 2013. If these proposed regulations are adopted, withholding under these rules would not be required on the notes. A significant modification of the

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notes which is treated as an exchange under applicable Treasury Regulations will cause the notes, for purposes of the grandfathering rules, to be deemed newly issued on the date of the modification. You are encouraged to consult with your own tax advisors regarding the possible implications of this legislation on an investment in the notes.

Certain U.S. federal estate tax considerations

If you are an individual and are not a resident of the United States (as specially defined for U.S. federal estate tax purposes) at the time of your death, the notes will not be included in your estate for U.S. federal estate tax purposes provided that, at the time of your death, interest on the notes qualifies for the portfolio interest exemption under the rules described above, without regard to the certification requirement.

Other Tax Consequences

Net Investment Income

For taxable years beginning after December 31, 2012, recently-enacted legislation is scheduled to impose a 3.8% tax on the “net investment income” of certain United States citizens and resident aliens and on the undistributed “net investment income” of certain estates and trusts. Among other items, “net investment income” generally would include interest on the notes and certain net gain from the sale, redemption, exchange, retirement or other taxable disposition of property, such as the notes, less certain deductions.

We encourage each prospective investor to consult its own tax advisor regarding the particular U.S. federal, state, local and foreign tax consequences of acquiring, owning and disposing of the notes, including the consequences of any proposed change in applicable laws.

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UNDERWRITING

Merrill Lynch, Pierce, Fenner & Smith Incorporated, Deutsche Bank Securities Inc. and Morgan Stanley & Co. LLC are acting as representatives of each of the underwriters named below. Subject to the terms and conditions set forth in a firm commitment underwriting agreement among us and the underwriters, we have agreed to sell to the underwriters, and each of the underwriters has agreed, severally and not jointly, to purchase from us, the principal amount of notes set forth opposite its name below.

Underwriter	Principal Amount of Notes
Merrill Lynch, Pierce, Fenner & Smith                        Incorporated	$
Deutsche Bank Securities Inc.
Morgan Stanley & Co. LLC
Total	$	250,000,000

Subject to the terms and conditions set forth in the underwriting agreement, the underwriters have agreed, severally and not jointly, to purchase all of the notes sold under the underwriting agreement if any of these notes are purchased. If an underwriter defaults, the underwriting agreement provides that the purchase commitments of the nondefaulting underwriters may be increased or the underwriting agreement may be terminated.

We have agreed to indemnify the underwriters and their controlling persons against certain liabilities in connection with this offering, including liabilities under the Securities Act, or to contribute to payments the underwriters may be required to make in respect of those liabilities.

The underwriters are offering the notes, subject to prior sale, when, as and if issued to and accepted by them, subject to approval of legal matters by their counsel, including the validity of the notes, and other conditions contained in the underwriting agreement, such as the receipt by the underwriters of officer’s certificates and legal opinions. The underwriters reserve the right to withdraw, cancel or modify offers to the public and to reject orders in whole or in part.

Commissions and Discounts

The representatives have advised us that the underwriters propose initially to offer the notes to the public at the public offering price set forth on the cover page of this prospectus supplement and to certain dealers at such price less a concession not in excess of     % of the principal amount of the notes. After the initial offering, the public offering price, concession or any other term of the offering may be changed.

The expenses of the offering, not including the underwriting discount, are estimated at $500,000 and are payable by us.

New Issue of Notes

The notes are a new issue of securities with no established trading market. We do not intend to apply for listing of the notes on any national securities exchange or for inclusion of the notes on any automated dealer quotation system. We have been advised by the underwriters that they presently intend to make a market in the notes after completion of the offering. However, they are under no obligation to do so and may discontinue any market-making activities at any time without any notice. We cannot assure the liquidity of the trading market for the notes or that an active public market for the notes will develop. If an active public trading market for the notes does not develop, the market price and liquidity of the notes may be adversely affected. If the notes are traded, they may trade at a discount from their initial offering price, depending on prevailing interest rates, the market for similar securities, our operating performance and financial condition, general economic conditions and other factors.

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Settlement

We expect that delivery of the notes will be made to investors on or about July     , 2012, which will be the fifth (5th) business day following the date of this prospectus supplement (such settlement being referred to as “T+5”). Under Rule 15c6-1 under the Securities Exchange Act of 1934, trades in the secondary market are required to settle in three business days, unless the parties to any such trade expressly agree otherwise. Accordingly, purchasers who wish to trade notes prior to the delivery of the notes hereunder will be required, by virtue of the fact that the notes initially settle in T+5, to specify an alternate settlement arrangement at the time of any such trade to prevent a failed settlement. Purchasers of the notes who wish to trade the notes prior to their date of delivery hereunder should consult their advisors.

No Sales of Similar Securities

We have agreed that we will not, for a period of five (5) business days after the date of this offering memorandum, without first obtaining the prior written consent of Merrill Lynch, Pierce, Fenner & Smith Incorporated, directly or indirectly, issue, sell, offer to contract or grant any option to sell, pledge, transfer or otherwise dispose of, any debt securities or securities exchangeable for or convertible into debt securities, except for the notes sold to the underwriters pursuant to the underwriting agreement.

Short Positions

In connection with the offering, the underwriters may purchase and sell the notes in the open market. These transactions may include short sales and purchases on the open market to cover positions created by short sales. Short sales involve the sale by the underwriters of a greater principal amount of notes than they are required to purchase in the offering. The underwriters must close out any short position by purchasing notes in the open market. A short position is more likely to be created if the underwriters are concerned that there may be downward pressure on the price of the notes in the open market after pricing that could adversely affect investors who purchase in the offering.

Similar to other purchase transactions, the underwriters’ purchases to cover the syndicate short sales may have the effect of raising or maintaining the market price of the notes or preventing or retarding a decline in the market price of the notes. As a result, the price of the notes may be higher than the price that might otherwise exist in the open market.

Neither we nor any of the underwriters make any representation or prediction as to the direction or magnitude of any effect that the transactions described above may have on the price of the notes. In addition, neither we nor any of the underwriters make any representation that the representatives will engage in these transactions or that these transactions, once commenced, will not be discontinued without notice.

Other Relationships

Some of the underwriters and their affiliates have engaged in, and may in the future engage in, investment banking and other commercial dealings in the ordinary course of business with us or our affiliates. In particular, affiliates of some of the underwriters are lenders under our $400 million senior secured revolving credit facility. Bank of America, N.A., an affiliate of Merrill Lynch, Pierce, Fenner & Smith Incorporated (“Merrill Lynch), acts as administrative agent under the revolving credit facility, Merrill Lynch acted as sole lead arranger and book-runner for the facility and Deutsche Bank Trust Company Americas acted as co-syndication agent. In connection with these transactions, the underwriters or their affiliates have received, or may in the future receive, customary fees, commissions and reimbursement of expenses.

In addition, in the ordinary course of their business activities, the underwriters and their affiliates may make or hold a broad array of investments and actively trade debt and equity securities (or related derivative securities) and financial instruments (including bank loans) for their own account and for the accounts of their

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customers. Such investments and securities activities may involve securities and/or instruments of ours or our affiliates. Certain of the underwriters or their affiliates that have a lending relationship with us routinely hedge their credit exposure to us consistent with their customary risk management policies. Typically, such underwriters and their affiliates would hedge such exposure by entering into transactions which consist of either the purchase of credit default swaps or the creation of short positions in our securities, including potentially the notes offered hereby. Any such short positions could adversely affect future trading prices of the notes offered hereby. The underwriters and their affiliates may also make investment recommendations and/or publish or express independent research views in respect of such securities or financial instruments and may hold, or recommend to clients that they acquire, long and/or short positions in such securities and instruments.

Notice to Prospective Investors in the European Economic Area

In relation to each Member State of the European Economic Area which has implemented the Prospectus Directive (each, a “Relevant Member State”), with effect from and including the date on which the Prospectus Directive is implemented in that Relevant Member State (the “Relevant Implementation Date”) no offer of notes may be made to the public in that Relevant Member State other than:

(i) to any legal entity which is a qualified investor as defined in the Prospectus Directive;

(ii) to fewer than 150 natural or legal persons (other than qualified investors as defined in the Prospectus Directive), as permitted under the Prospectus Directive, subject to obtaining the prior consent of the representatives; or

(iii) in any other circumstances falling within Article 3(2) of the Prospectus Directive;

provided that no such offer of notes shall require Westlake or any of the underwriters to publish a prospectus pursuant to Article 3 of the Prospectus Directive or supplement a prospectus pursuant to Article 16 of the Prospectus Directive.

This prospectus supplement and the accompanying prospectus have been prepared on the basis that any offer of notes in any Relevant Member State will be made pursuant to an exemption under the Prospectus Directive from the requirement to publish a prospectus for offers of notes. Accordingly any person making or intending to make an offer in that Relevant Member State of notes which are the subject of the offering contemplated in this prospectus supplement and the accompanying prospectus may only do so in circumstances in which no obligation arises for Westlake or any of the underwriters to publish a prospectus pursuant to Article 3 of the Prospectus Directive in relation to such offer. Neither Westlake nor the underwriters have authorized, nor do they authorize, the making of any offer of notes in circumstances in which an obligation arises for Westlake or the underwriters to publish a prospectus for such offer.

For the purpose of the above provisions, the expression “an offer to the public” in relation to any notes in any Relevant Member State means the communication in any form and by any means of sufficient information on the terms of the offer and the notes to be offered so as to enable an investor to decide to purchase or subscribe the notes, as the same may be varied in the Relevant Member State by any measure implementing the Prospectus Directive in the Relevant Member State and the expression “Prospectus Directive” means Directive 2003/71/EC and amendments thereto (including the 2010 PD Amending Directive) and includes any relevant implementing measure in the Relevant Member State and the expression “2010 PD Amending Directive” means Directive 2010/73/EU.

Notice to Prospective Investors in the United Kingdom

In addition, in the United Kingdom, this document is being distributed only to, and is directed only at, and any offer subsequently made may only be directed at persons who are “qualified investors” (as defined in the Prospectus Directive) (i) who have professional experience in matters relating to investments falling within

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Article 19(5) of the Financial Services and Markets Act 2000 (Financial Promotion) Order 2005, as amended (the “Order”) and/or (ii) who are high net worth companies (or persons to whom it may otherwise be lawfully communicated) falling within Article 49(2)(a) to (d) of the Order (all such persons together being referred to as “relevant persons”). This document must not be acted on or relied on in the United Kingdom by persons who are not relevant persons. In the United Kingdom, any investment or investment activity to which this document relates is only available to, and will be engaged in with, relevant persons.

Notice to Prospective Investors in Switzerland

This prospectus supplement and the accompanying prospectus do not constitute an issue prospectus pursuant to Article 652a or Article 1156 of the Swiss Code of Obligations and the notes will not be listed on the SIX Swiss Exchange. Therefore, this prospectus supplement and the accompanying prospectus may not comply with the disclosure standards of the listing rules (including any additional listing rules or prospectus schemes) of the SIX Swiss Exchange. Accordingly, the notes may not be offered to the public in or from Switzerland, but only to a selected and limited circle of investors who do not subscribe to the notes with a view to distribution. Any such investors will be individually approached by the underwriters from time to time.

Notice to Prospective Investors in the Dubai International Financial Centre

This prospectus supplement and the accompanying prospectus relate to an Exempt Offer in accordance with the Offered Securities Rules of the Dubai Financial Services Authority (“DFSA”). This prospectus supplement and the accompanying prospectus are intended for distribution only to persons of a type specified in the Offered Securities Rules of the DFSA. They must not be delivered to, or relied on by, any other person. The DFSA has no responsibility for reviewing or verifying any documents in connection with Exempt Offers. The DFSA has not approved this prospectus supplement and the accompanying prospectus nor taken steps to verify the information set forth herein or therein and has no responsibility for the prospectus supplement or the accompanying prospectus. The notes to which this prospectus supplement and the accompanying prospectus relates may be illiquid and/or subject to restrictions on their resale. Prospective purchasers of the notes offered should conduct their own due diligence on the notes. If you do not understand the contents of this prospectus supplement or the accompanying prospectus you should consult an authorized financial advisor.

Notice to Prospective Investors in Bermuda

The offering of the notes to investors in Bermuda may constitute carrying on business in Bermuda for purposes of the Companies Act 1981 (the “Bermuda Companies Act”). Carrying on business in Bermuda by an overseas company requires a license under Section 134 of the Bermuda Companies Act. Westlake is an overseas company and is not licensed under Section 134 of the Bermuda Companies Act. As long as Westlake does not have a physical presence in Bermuda and the notes are offered to Bermuda investors only at such time as they are outside of Bermuda, such offering will generally not constitute carrying on business in Bermuda.

The offering of the notes to investors in Bermuda may, in some circumstances, require a license to carry on investment business under the Investment Business Act 2003 of Bermuda. However, such requirement will only apply where the person or entity offering the notes has a physical presence in Bermuda. Neither Westlake nor any of the underwriters has a physical presence in Bermuda.

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LEGAL MATTERS

Certain legal matters in connection with the offering of the notes will be passed upon for us by Baker Botts L.L.P., Houston, Texas and will be passed upon for the underwriters by Mayer Brown LLP, Chicago, Illinois.

EXPERTS

The financial statements and management’s assessment of the effectiveness of internal control over financial reporting (which is included in Management’s Report on Internal Control over Financial Reporting) incorporated in this prospectus supplement and the accompanying prospectus by reference to our Annual Report on Form 10-K for the year ended December 31, 2011 have been so incorporated in reliance on the report of PricewaterhouseCoopers LLP, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting.

WHERE YOU CAN FIND MORE INFORMATION

We file reports, proxy statements and other information with the SEC. You can read and copy any materials we file with the SEC at the SEC’s public reference room at 100 F Street, N.E., Room 1850, Washington, D.C. 20549. You can obtain information about the operation of the SEC’s public reference room by calling the SEC at 1-800-SEC-0330. The SEC also maintains a Web site that contains information we file electronically with the SEC, which you can access over the Internet at http://www.sec.gov. You can obtain information about us at the offices of the New York Stock Exchange, 20 Broad Street, New York, New York 10005.

Our Web site is located at http: //www.westlake.com. Our Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and other filings with the SEC are available, free of charge, through our Web site, as soon as reasonably practicable after those reports or filings are electronically filed with or furnished to the SEC. Information on our Web site or any other website is not incorporated by reference in this prospectus supplement or the accompanying prospectus and does not constitute a part of this prospectus supplement or the accompanying prospectus.

This prospectus relate to a registration statement we have filed with the SEC. As permitted by SEC rules, this prospectus does not contain all of the information we have included in the registration statement and the accompanying exhibits and schedules we file with the SEC. You may refer to the registration statement, the exhibits and the schedules for more information about us and our securities. The registration statement, exhibits and schedules are available at the SEC’s public reference room or through its Web site.

We are incorporating by reference information we file with the SEC, which means that we are disclosing important information to you by referring you to those documents. The information we incorporate by reference is an important part of this prospectus supplement and the accompanying prospectus, and later information that we file with the SEC automatically will update and supersede this information. We incorporate by reference the documents listed below and any future filings we make with the SEC under Section 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934 until we sell all the securities:

• our annual report on Form 10-K for the fiscal year ended December 31, 2011;

• our quarterly report on Form 10-Q for the quarter ended March 31, 2012; and

• our current reports on Form 8-K filed on January 13, 2012, February 1, 2012 (excluding any information furnished pursuant to item 7.01), and May 25, 2012.

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You may request a copy of these filings (other than an exhibit to those filings unless we have specifically incorporated that exhibit by reference into the filing), at no cost, by writing or telephoning us at the following address:

Westlake Chemical Corporation

2801 Post Oak Boulevard, Suite 600

Houston, Texas 77056

Attention: Investor Relations

Telephone: (713) 960-9111

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Prospectus

Westlake Chemical Corporation

Debt Securities

Preferred Stock

Common Stock

Warrants

We may issue and sell from time to time:

• our debt securities;

• shares of our common stock;

• shares of our preferred stock;

• warrants to purchase such securities; or

• guarantees of our debt securities.

TTWF LP, our principal stockholder in which three of our directors have indirect ownership interests, may sell from time to time up to 4,500,000 shares of our common stock.

This prospectus provides you with a general description of the securities that may be offered. We will provide the specific terms of the securities in supplements to this prospectus. You should read this prospectus and any supplement carefully before you invest. Our common stock is listed on the New York Stock Exchange under the symbol “WLK.”

Investing in our securities involves risk. You should carefully consider the risk factors described under “Risk Factors” beginning on page 4 of this prospectus before you make any investment in our securities.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined whether this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus is September 30, 2011.

Table of Contents

About This Prospectus	1
About Westlake Chemical Corporation	2
The Subsidiary Guarantors	3
Risk Factors	4
Cautionary Statements About Forward-Looking Statements	8
Use Of Proceeds	10
Ratio Of Earnings To Fixed Charges	10
Description Of Debt Securities	11
Description Of Capital Stock	21
Description Of Warrants	27
Selling Stockholder	28
Plan Of Distribution	30
Legal Opinions	32
Experts	32
Where You Can Find More Information	32

ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement that we have filed with the Securities and Exchange Commission using a “shelf” registration process. Using this process, we and the selling stockholder may sell any combination of the securities described in this prospectus in one or more offerings. This prospectus provides you with a general description of the securities that may be offered. Each time securities are sold pursuant to this prospectus, we will provide a prospectus supplement and, if applicable, a pricing supplement that will describe the specific terms of that offering. The prospectus supplement and any pricing supplement may also add to, update or change the information contained in this prospectus. Please carefully read this prospectus, the prospectus supplement and any pricing supplement together with the information contained in the documents we refer to under the heading “Where You Can Find More Information.”

You should rely only on the information we have provided or incorporated by reference in this prospectus, the prospectus supplement and any pricing supplement. Neither we nor the selling stockholder have authorized any person, including any salesman or broker, to provide you with additional or different information. We and the selling stockholder are not making an offer of these securities in any jurisdiction where the offer is not permitted. You should assume that the information in this prospectus, the accompanying prospectus supplement and any pricing supplement is accurate only as of the date on its cover page and that any information we have incorporated by reference is accurate only as of the date of the document incorporated by reference.

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ABOUT WESTLAKE CHEMICAL CORPORATION

We are a vertically integrated manufacturer and marketer of basic chemicals, vinyls, polymers and PVC building products. Our products include some of the most widely used chemicals in the world, which are fundamental to many diverse consumer and industrial markets, including flexible and rigid packaging, automotive products, coatings, residential and commercial construction as well as other durable and non-durable goods. We operate in two principal business segments, Olefins and Vinyls, and we are one of the few North American integrated producers of vinyls with substantial downstream integration into polyvinyl chloride, or PVC, building products.

We began operations in 1986 after our first polyethylene plant, an Olefins segment business, near Lake Charles, Louisiana was acquired from Occidental Petroleum Corporation. We began our vinyls operations in 1990 with the acquisition of a vinyl chloride monomer, or VCM, plant in Calvert City, Kentucky from the Goodrich Corporation. In 1992, we commenced our Vinyls segment PVC building products operations after acquiring three PVC pipe plants. Since 1986, we have grown rapidly into an integrated producer of petrochemicals, polymers and PVC building products. We achieved this by acquiring 18 plants (excluding plants that have subsequently been permanently closed or disposed of), constructing eight new plants (including our joint venture in China) and completing numerous capacity or production line expansions. Since 2007, we have closed four PVC building products plants due to the economic downturn.

We benefit from highly integrated production facilities that allow us to process raw materials into higher value-added chemicals and PVC building products. As of September 28, 2011, we have 11.8 billion pounds per year of aggregate production capacity at 13 manufacturing sites in North America. We also have a 59% interest in a joint venture in China that operates a vinyls facility.

We are a Delaware corporation with our principal executive offices located at 2801 Post Oak Boulevard, Suite 600, Houston, Texas 77056. Our telephone number at such address is (713) 960-9111.

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THE SUBSIDIARY GUARANTORS

One or more of our following direct or indirect wholly-owned subsidiaries may fully and unconditionally guarantee any series of debt securities offered by this prospectus, as set forth in a related prospectus supplement:

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

These subsidiaries are sometimes referred to in this prospectus as possible Subsidiary Guarantors. The term “Subsidiary Guarantors” with respect to a series of debt securities refers to those subsidiaries listed above that guarantee that series of debt securities. The applicable prospectus supplement will name the Subsidiary Guarantors, if any, for that series of debt securities and will describe the terms of the guarantee by the Subsidiary Guarantors.

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RISK FACTORS

An investment in our securities involves a high degree of risk. You should carefully consider the risk factors and all of the other information included in, or incorporated by reference into, this prospectus, including those in Item 1A. “Risk Factors” in our Annual Report on Form 10-K for the year ended December 31, 2010, in evaluating an investment in our securities. If any of these risks were to occur, our business, financial condition or results of operations could be adversely affected. In that case, the trading price of our common or preferred stock or value of our debt securities could decline and you could lose all or part of your investment. When we offer and sell any securities pursuant to a prospectus supplement, we may include additional risk factors relevant to such securities in the prospectus supplement.

Risks Related to our Principal Stockholder

We will be controlled by our principal stockholder, TTWF LP, and its affiliates as long as they own a majority of our common stock, and our other stockholders will be unable to affect the outcome of stockholder voting during that time. Our interests may conflict with those of the principal stockholder and its affiliates, and we may not be able to resolve these conflicts on terms possible in arms-length transactions.

As long as TTWF LP, which as of the date of this prospectus owns approximately 69.1% of our common stock (the “principal stockholder” or the “selling stockholder”) and its affiliates (the “principal stockholder affiliates”) own a majority of our outstanding common stock, they will be able to exert significant control over us, and our other stockholders, by themselves, will not be able to affect the outcome of any stockholder vote. As a result, the principal stockholder, subject to any fiduciary duty owed to our minority stockholders under Delaware law, will be able to control all matters affecting us (some of which may present conflicts of interest), including:

• the composition of our board of directors and, through the board, any determination with respect to our business direction and policies, including the appointment and removal of officers and the determination of compensation;

• any determinations with respect to mergers or other business combinations or the acquisition or disposition of assets;

• our financing decisions, capital raising activities and the payment of dividends; and

• amendments to our amended and restated certificate of incorporation or amended and restated bylaws.

The principal stockholder will be permitted to transfer a controlling interest in us without being required to offer our other stockholders the ability to participate or realize a premium for their shares of common stock. A sale of a controlling interest to a third party may adversely affect the market price of our common stock and our business and results of operations because the change in control may result in a change of management decisions and business policy. Because we have elected not to be subject to Section 203 of the General Corporation Law of the State of Delaware, the principal stockholder may find it easier to sell its controlling interest to a third party than if we had not so elected. See “Description of Capital Stock—Delaware Business Combination Statute” for a description of Section 203 and the potential positive and negative consequences, depending on the circumstances, of electing not to be subject to it.

In addition to any conflicts of interest that arise in the foregoing areas, our interests may conflict with those of the principal stockholder affiliates in a number of other areas, including:

• business opportunities that may be presented to the principal stockholder affiliates and to our officers and directors associated with the principal stockholder affiliates, and competition between the principal stockholder affiliates and us within the same lines of business;

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• the solicitation and hiring of employees from each other; and

• agreements with the principal stockholder affiliates relating to corporate services that may be material to our business.

We may not be able to resolve any potential conflicts with the principal stockholder affiliates, and even if we do, the resolution may be less favorable than if we were dealing with an unaffiliated party, particularly if the conflicts are resolved while we are controlled by the principal stockholder affiliates. Our amended and restated certificate of incorporation provides that the principal stockholder affiliates have no duty to refrain from engaging in activities or lines of business similar to ours and that the principal stockholder affiliates will not be liable to us or our stockholders for failing to present specified corporate opportunities to us. See “Description of Capital Stock—Transactions and Corporate Opportunities.”

Risks Related to the Common Stock

Substantial sales of our common stock by the principal stockholder or us could cause our stock price to decline and issuances by us may dilute our stockholders’ ownership interest in our company.

We are unable to predict whether significant amounts of our common stock will be sold by the principal stockholder. Any sales of substantial amounts of our common stock in the public market by the principal stockholder or us, or the perception that these sales might occur, could lower the market price of our common stock. Further, if we issue additional equity securities to raise additional capital, our stockholders’ ownership interest in our company may be diluted and the value of their investment may be reduced.

The price of our common stock may be volatile.

The market price of our common stock could be subject to significant fluctuations. Among the factors that could affect our stock price are:

• our operating and financial performance and prospects;

• quarterly variations in the rate of growth of our financial indicators, such as earnings per share, net income and revenues;

• changes in revenue or earnings estimates or publication of research reports by analysts;

• speculation in the press or investment community;

• strategic actions by us or our competitors, such as acquisitions or restructurings;

• sales of our common stock by stockholders;

• actions by institutional investors or by the principal stockholder;

• fluctuations in oil and gas prices;

• general market conditions, including fluctuations in commodity prices; and

• U.S. and international economic, legal and regulatory factors unrelated to our performance.

The stock markets in general have experienced extreme volatility in recent years that has at times been unrelated to the operating performance of particular companies. These broad market fluctuations may adversely affect the trading price of our common stock and, as a result, an investment in our common stock.

If we are unable to pay regular dividends on our common stock, our stockholders may not receive funds without selling their common stock.

Shortly following our initial public offering in 2004, we paid our initial regular quarterly dividend of $0.02125 per share. We have paid regular quarterly dividends since our initial dividend. On September 13, 2011, we paid a quarterly dividend of $0.07375 per share to holders of our common stock. Any payment of future

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dividends will be at the discretion of our board of directors and will depend on, among other things, our earnings, financial condition, capital requirements, level of indebtedness, statutory and contractual restrictions applying to the payment of dividends, and other considerations that our board of directors deems relevant. The agreements governing our 6 ⁵/8% senior notes due 2016, 6 ³/4% senior notes due 2029, 6 ³/4% senior notes due 2032, each of our series of 6 ¹/2% senior notes due 2035 and revolving credit facility also include limitations on our payment of dividends. Accordingly, our stockholders may have to sell some or all of their common stock in order to generate cash flow from their investment. Our stockholders may not receive a gain on their investment when they sell their common stock and they may lose the entire amount of the investment.

Provisions in our charter documents or Delaware law may inhibit a takeover, which could adversely affect the value of our common stock.

Our amended and restated certificate of incorporation and amended and restated bylaws, as well as Delaware corporate law, contain provisions that could delay or prevent a change of control or changes in our management that a stockholder might consider favorable. These provisions apply even if the offer may be considered beneficial by some of our stockholders. If a change of control or change in management is delayed or prevented, the market price of our common stock could decline. Please read “Description of Capital Stock” for a description of these provisions.

Risks Related to the Debt Securities

Our holding company structure may affect our ability to make payments on the debt securities. Holders of debt securities may be structurally subordinated to the creditors of our subsidiaries.

We currently conduct our operations through subsidiaries, and our operating income and cash flow are generated by our subsidiaries. As a result, cash we obtain from our subsidiaries is the principal source of funds necessary to meet our debt service obligations. Contractual provisions or laws, as well as our subsidiaries’ financial condition and operating requirements, may limit our ability to obtain cash from our subsidiaries that we require to pay our debt service obligations, including payments on the debt securities. In addition, holders of the debt securities will have a junior position to the claims of creditors, including trade creditors and tort claimants, of our subsidiaries to the extent that such subsidiaries do not guarantee such debt securities. In the event of a bankruptcy, liquidation or reorganization of any of our non-guarantor subsidiaries, holders of that subsidiary’s indebtedness and its trade creditors will generally be entitled to payment of their claims from the assets of the subsidiary before any assets are made available for distribution to us.

A holder’s right to receive payments on the debt securities is effectively subordinated to the rights of our existing and future secured creditors. Further, the guarantees of the senior debt securities by the Subsidiary Guarantors are effectively subordinated to the guarantors’ existing and future secured indebtedness.

Holders of our secured indebtedness and the secured indebtedness of the Subsidiary Guarantors will have claims that are prior to the claims of holders of the senior debt securities to the extent of the value of the assets securing that other indebtedness. Notably, we and certain of our subsidiaries, including the Subsidiary Guarantors, are parties to a credit facility, which is secured by liens on, among other things, our accounts receivable and inventory. The senior debt securities will be effectively subordinated to that secured indebtedness. In the event of any distribution or payment of our assets in any foreclosure, dissolution, winding-up, liquidation, reorganization or other bankruptcy proceeding, holders of secured indebtedness will have prior claim to our assets that constitute their collateral. Holders of the senior debt securities will participate ratably with all holders of our senior unsecured indebtedness, and potentially with all of our other general creditors, based upon the respective amounts owed to each holder or creditor, in our remaining assets. We may apply proceeds of certain asset sales to reduce our secured indebtedness or other secured obligations, but such application will not permanently reduce our ability to incur secured indebtedness and other secured obligations under the indenture in

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the future. In any of the foregoing events, we cannot assure you that there will be sufficient assets to pay amounts due on the senior debt securities. As a result, holders of the senior debt securities may receive less, ratably, than holders of secured indebtedness.

A holder’s right to receive payments on the debt securities could be adversely affected if any of our non-guarantor subsidiaries declares bankruptcy, liquidates or reorganizes.

Some but not all of our subsidiaries may guarantee the debt securities. In the event of a bankruptcy, liquidation or reorganization of any of our non-guarantor subsidiaries, holders of that subsidiary’s indebtedness and its trade creditors will generally be entitled to payment of their claims from the assets of the subsidiary before any assets are made available for distribution to us.

Federal and state statutes allow courts, under specific circumstances, to void guarantees and require holders of the debt securities to return payments received from guarantors.

Under the federal bankruptcy law and comparable provisions of state fraudulent transfer laws, a guarantee could be voided or claims in respect of a guarantee could be subordinated to all other debts of the applicable guarantor if, among other things, the guarantor, at the time it incurred the indebtedness evidenced by its guarantee, received less than reasonably equivalent value or fair consideration for the incurrence of such guarantee and either:

• was insolvent or rendered insolvent by reason of such incurrence; or

• was engaged or about to engage in a business or transaction for which the guarantor’s remaining assets constituted unreasonably small capital; or

• intended to incur, or believed that it would incur, debts beyond its ability to pay such debts as they mature.

In addition, any payment by that guarantor pursuant to its guarantee could be voided and required to be returned to the guarantor or to a fund for the benefit of the creditors of the guarantor.

The measures of insolvency for purposes of these fraudulent transfer laws will vary depending upon the law applied in any proceeding to determine whether a fraudulent transfer has occurred. Generally, a guarantor would be considered insolvent if, at the relevant time, the sum of its debts and other liabilities, including contingent liabilities, was greater than the sum of its assets at a fair valuation, and a guarantor that was generally not then paying its debts as they became due would be presumed to be insolvent.

We may incur additional debt ranking equal to the debt securities.

If we incur any additional debt that ranks equally with the debt securities, the holders of that debt will be entitled to share ratably with the holders of the debt securities in any proceeds distributed in connection with any insolvency, liquidation, reorganization, dissolution or other winding-up of our company. This may have the effect of reducing the amount of proceeds paid to a holder of debt securities.

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CAUTIONARY STATEMENTS ABOUT FORWARD-LOOKING STATEMENTS

The Private Securities Litigation Reform Act of 1995 provides safe harbor provisions for forward-looking information. Certain of the statements contained in this prospectus are forward-looking statements. All statements, other than statements of historical facts, included in this prospectus that address activities, events or developments that we expect, project, believe or anticipate will or may occur in the future are forward-looking statements. Forward-looking statements can be identified by the use of words such as “believes,” “intends,” “may,” “should,” “could,” “anticipates,” “expected” or comparable terminology, or by discussions of strategies or trends. Although we believe that the expectations reflected in such forward-looking statements are reasonable, we cannot give any assurances that these expectations will prove to be correct. Forward-looking statements relate to matters such as:

• future operating rates, margins, cash flow and demand for our products;

• industry market outlook;

• production capacities;

• our ability to borrow additional funds under our credit facility;

• our ability to meet our liquidity needs;

• our intended quarterly dividends;

• future capacity additions and expansions in the industry;

• timing, funding and results of the expansion programs at our Lake Charles and Calvert City complexes;

• timing, funding and results of the planned new chlor-alkali plant in Geismar;

• health of our customer base;

• compliance with present and future environmental regulations and costs associated with environmentally related penalties, capital expenditures, remedial actions and proceedings, including any new laws, regulations or treaties that may come into force to limit or control carbon dioxide and other greenhouse gases emissions or to address other issues of climate change;

• the utilization of net operating loss carryforwards;

• effects of pending legal proceedings; and

• timing of and amount of capital expenditures.

We have based these statements on assumptions and analyses in light of our experience and perception of historical trends, current conditions, expected future developments and other factors we believe were appropriate in the circumstances when the statements were made. Forward-looking statements by their nature involve substantial risks and uncertainties that could significantly impact expected results, and actual future results could differ materially from those described in such statements. While it is not possible to identify all factors, we continue to face many risks and uncertainties. Among the factors that could cause actual future results to differ materially are the risks and uncertainties discussed under “Risk Factors” in this prospectus and in our most recent Annual Report on Form 10-K and those described from time to time in our other filings with the SEC including, but not limited to, the following:

• general economic and business conditions;

• the cyclical nature of the chemical industry;

• the availability, cost and volatility of raw materials and energy;

• uncertainties associated with the United States and worldwide economies, including those due to the global economic slowdown, the credit crisis and political tensions in the Middle East and elsewhere;

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• current and potential governmental regulatory actions in the United States and regulatory actions and political unrest in other countries;

• industry production capacity and operating rates;

• the supply/demand balance for our products;

• competitive products and pricing pressures;

• instability in the credit and financial markets;

• access to capital markets;

• terrorist acts;

• operating interruptions (including leaks, explosions, fires, weather-related incidents, mechanical failure, unscheduled downtime, labor difficulties, transportation interruptions, spills and releases and other environmental risks);

• changes in laws or regulations;

• technological developments;

• our ability to implement our business strategies; and

• creditworthiness of our customers.

Many of these factors are beyond our ability to control or predict. Any of the factors, or a combination of these factors, could materially affect our future results of operations and the ultimate accuracy of the forward-looking statements. These forward-looking statements are not guarantees of our future performance, and our actual results and future developments may differ materially from those projected in the forward-looking statements. Management cautions against putting undue reliance on forward-looking statements or projecting any future results based on such statements or present or prior earnings levels. Every forward-looking statement speaks only as of the date of the particular statement, and we undertake no obligation to publicly update or revise any forward-looking statement.

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USE OF PROCEEDS

Unless we inform you otherwise in the prospectus supplement, we expect to use the net proceeds from the sale of securities for general corporate purposes. These purposes may include:

• repayment or refinancing of debt;

• acquisitions;

• working capital;

• capital expenditures; and

• repurchases and redemptions of securities.

Pending any specific application, we may initially invest funds in short-term marketable securities or apply them to the reduction of short-term indebtedness.

We will not receive any proceeds from the sale of any shares of our common stock that may be sold by the selling stockholder.

RATIO OF EARNINGS TO FIXED CHARGES

We have presented in the table below our historical consolidated ratio of earnings to fixed charges for the periods shown.

	Years Ended December 31,											Six Months Ended June 30, 2011
	2010		2009		2008			2007		2006
Ratio of earnings to fixed charges		7.2x		2.5x		—	(1)		5.5x		9.7x		8.7x

(1) Earnings for 2008 were insufficient to cover fixed charges by $61.8 million.

We have computed the ratios of earnings to fixed charges by dividing earnings by fixed charges. For this purpose, “earnings” consist of earnings before income taxes plus fixed charges and equity distributions less net capitalized interest and equity investment income. “Fixed charges” consist of interest expense, capitalized interest and that portion of operating lease rental expense (one-third) we have deemed to represent the interest factor of such expense.

No shares of our preferred stock are currently issued or outstanding, therefore no dividends accrued on any shares of our preferred stock for any period presented. Accordingly, the ratio of earnings to combined fixed charges and preferred stock dividends is the same as the ratio of earnings to fixed charges.

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DESCRIPTION OF DEBT SECURITIES

The debt securities covered by this prospectus will be our general unsecured obligations. We will issue senior debt securities under an indenture dated as of January 1, 2006, as amended or supplemented from time to time, between us, the 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. We refer to this indenture as the senior indenture. We will issue subordinated debt securities under an indenture to be entered into among us, the possible Subsidiary Guarantors, and a trustee we will name in the prospectus supplement relating to subordinated debt securities. We refer to this indenture as the subordinated indenture. We refer to the senior indenture and the subordinated indenture collectively as the indentures. The indentures are substantially identical, except for provisions relating to subordination.

We have summarized material provisions of the indentures, the debt securities and the guarantees below. This summary is not complete. We have filed the form of the senior indenture and the form of the subordinated indenture with the SEC as exhibits to the registration statement, and you should read the indentures for provisions that may be important to you. Please read “Where You Can Find More Information.”

In this summary description of the debt securities, unless we state otherwise or the context clearly indicates otherwise, all references to “we,” “us,” or “our” refer to Westlake Chemical Corporation only and not to any of its subsidiaries.

General

Neither indenture limits the amount of debt securities that may be issued under that indenture, and neither limits the amount of other unsecured debt or securities that we may issue. We may issue debt securities under the indentures from time to time in one or more series. As of June 30, 2011, $753.6 million of senior debt securities were outstanding under the senior indenture, which includes $250.0 million aggregate principal amount of 6 ⁵/8% senior notes due 2016 (less the unamortized discount of $0.4 million), $100.0 million aggregate principal amount of 6 ³/4% senior notes due 2029, $250.0 million aggregate principal amount of 6 ¹/2% senior notes due 2032, $89.0 million aggregate principal amount of 6 ¹/2% senior notes due 2035 and $65.0 million aggregate principal amount of 6 ¹/2% senior notes due 2035 (collectively the “Outstanding Senior Notes”). No securities are outstanding under the subordinated indenture.

We are not obligated to issue all debt securities of one series at the same time and, unless otherwise provided in the prospectus supplement, we may reopen a series, without the consent of the holders of the debt securities of that series, for the issuance of additional debt securities of that series. Additional debt securities of a particular series will have the same terms and conditions as outstanding debt securities of such series, except for the date of original issuance and the offering price, and will be consolidated with, and form a single series with, such outstanding debt securities.

The senior debt securities will constitute our senior unsecured indebtedness and will rank equally in right of payment with all of our other unsecured and unsubordinated debt and senior in right of payment to all of our subordinated indebtedness. The senior debt securities will be effectively subordinated to, and thus have a junior position to, our secured indebtedness with respect to the assets securing that indebtedness. The subordinated debt securities will rank junior to all of our senior indebtedness and may rank equally with or senior to other subordinated indebtedness we may issue from time to time.

We currently conduct our operations through subsidiaries, and our operating income and cash flow are generated by our subsidiaries. As a result, cash we obtain from our subsidiaries is the principal source of funds necessary to meet our debt service obligations. Contractual provisions or laws, as well as our subsidiaries’ financial condition and operating requirements, may limit our ability to obtain cash from our subsidiaries that we

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require to pay our debt service obligations, including payments on the debt securities. In addition, holders of the debt securities will have a junior position to the claims of creditors, including trade creditors and tort claimants, of our subsidiaries to the extent that such subsidiaries do not guarantee such debt securities.

Neither indenture contains any covenants or other provisions designed to protect holders of the debt securities in the event we participate in a highly leveraged transaction or upon a change of control. The indentures also do not contain provisions that give holders of the debt securities the right to require us to repurchase their securities in the event of a decline in our credit rating for any reason, including as a result of a takeover, recapitalization or similar restructuring or otherwise.

Ranking

We and certain of our subsidiaries, including the Subsidiary Guarantors, are parties to a revolving credit facility, which is secured by liens on, among other things, our accounts receivable and inventory. The senior debt securities will be effectively subordinated to that secured indebtedness. As of June 30, 2011, we had no outstanding borrowings and outstanding letters of credit totaling $17.7 million under the revolving credit facility. In the event of any distribution or payment of our assets in any foreclosure, dissolution, winding-up, liquidation, reorganization or other bankruptcy proceeding, holders of secured indebtedness will have prior claim to our assets that constitute their collateral. Holders of the senior debt securities will participate ratably with all holders of our senior unsecured indebtedness, and potentially with all of our other general creditors, based upon the respective amounts owed to each holder or creditor, in our remaining assets. See “Risk Factors—Risks Related to the Debt Securities—A holder’s right to receive payments on the debt securities is effectively subordinated to the rights of our existing and future secured creditors. Further, the guarantees of the senior debt securities by the Subsidiary Guarantors are effectively subordinated to the guarantors’ existing and future secured indebtedness.”

The senior debt securities will rank equally with all of our other unsecured and unsubordinated indebtedness and the unsecured and unsubordinated indebtedness of the Subsidiary Guarantors. As of June 30, 2011, we had an aggregate of $764.5 million of unsecured and unsubordinated indebtedness, consisting of the Outstanding Senior Notes and a $10.9 million loan from the proceeds of tax-exempt waste disposal revenue bonds.

Under the subordinated indenture, payment of the principal of and any premium and interest on the subordinated debt securities will generally be subordinated and junior in right of payment to the prior payment in full of all Senior Debt. As of June 30, 2011, we had an aggregate of $764.5 million of Senior Debt.

Terms

The prospectus supplement relating to any series of debt securities being offered will include specific terms relating to the offering. These terms will include some or all of the following:

• whether the debt securities will be senior or subordinated debt securities;

• the title of the debt securities;

• the total principal amount of the debt securities;

• whether we will issue the debt securities in individual certificates to each holder or in the form of temporary or permanent global securities held by a depositary on behalf of holders;

• the date or dates on which the principal of and any premium on the debt securities will be payable;

• any interest rate, the date from which interest will accrue, interest payment dates and record dates for interest payments;

• whether and under what circumstances we will pay any additional amounts with respect to the debt securities;

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• whether debt securities are entitled to any guarantee of any Subsidiary Guarantors and the identity of any such Subsidiary Guarantors for that series and the terms of such guarantee if different than those set forth in the applicable indenture;

• the place or places where payments on the debt securities will be payable;

• any provisions for optional redemption or early repayment;

• any sinking fund or other provisions that would obligate us to redeem, purchase or repay the debt securities;

• the denominations in which we will issue the debt securities if other than $1,000 and integral multiples of $1,000;

• whether payments on the debt securities will be payable in foreign currency or currency unit or another form and whether payments will be payable by reference to any index or formula;

• the portion of the principal amount of debt securities that will be payable if the maturity is accelerated, if other than the entire principal amount;

• any additional means of defeasance of the debt securities, any additional conditions or limitations to defeasance of the debt securities or any changes to those conditions or limitations;

• any changes or additions to the events of default or covenants described in this prospectus;

• any restrictions or other provisions relating to the transfer or exchange of debt securities;

• any terms for the conversion or exchange of the debt securities for other securities;

• with respect to the subordinated indenture, any changes to the subordination provisions for the subordinated debt securities; and

• any other terms of the debt securities not inconsistent with the applicable indenture.

We may sell the debt securities at a discount, which may be substantial, below their stated principal amount. These debt securities may bear no interest or interest at a rate that at the time of issuance is below market rates. If we sell these debt securities, we will describe in the prospectus supplement any material United States federal income tax consequences and other special considerations.

If we sell any of the debt securities for any foreign currency or currency unit or if payments on the debt securities are payable in any foreign currency or currency unit, we will describe in the prospectus supplement the restrictions, elections, tax consequences, specific terms and other information relating to those debt securities and the foreign currency or currency unit.

Subordination

Under the subordinated indenture, payment of the principal of and any premium and interest on the subordinated debt securities will generally be subordinated and junior in right of payment to the prior payment in full of all Senior Debt. Unless we inform you otherwise in the prospectus supplement, we may not make any payment of principal of or any premium or interest on the subordinated debt securities if:

• we fail to pay the principal, interest, premium or any other amounts on any Senior Debt when due; or

• we default in performing any other covenant (a “covenant default”) on any Senior Debt that we have designated if the covenant default allows the holders of that Senior Debt to accelerate the maturity of the Senior Debt they hold.

Unless we inform you otherwise in the prospectus supplement, a covenant default will prevent us from paying the subordinated debt securities only for up to 179 days after holders of the designated Senior Debt give the trustee for the subordinated debt securities notice of the covenant default.

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The subordination does not affect our obligation, which is absolute and unconditional, to pay, when due, the principal of and any premium and interest on the subordinated debt securities. In addition, the subordination does not prevent the occurrence of any default under the subordinated indenture.

The subordinated indenture does not limit the amount of Senior Debt that we may incur. As a result of the subordination of the subordinated debt securities, if we become insolvent, holders of subordinated debt securities may receive less on a proportionate basis than other creditors.

Unless we inform you otherwise in the prospectus supplement, “Senior Debt” will mean,

• all indebtedness or obligations for borrowed money;

• all obligations evidenced by notes, bonds, debentures or other similar instruments;

• all obligations in respect of letters of credit or other similar instruments (or reimbursement obligations with respect thereto), other than standby letters of credit, bid or performance bonds and other obligations issued in the ordinary course of business to the extent not drawn or, to the extent drawn, if such drawing is reimbursed not later than the third business day following demand for reimbursement;

• all obligations to pay the deferred and unpaid purchase price of property or services, except trade payables and accrued expenses incurred in the ordinary course of business;

• all capitalized lease obligations;

• all debt of other persons secured by a lien on any asset of ours, whether or not such debt is assumed by us; and

• all debt of other persons guaranteed by us, to the extent of such guarantee;

unless the indebtedness states that it is not senior to the subordinated debt securities or our other junior debt.

Guarantees

Each of the Subsidiary Guarantors, if any, with respect to a series of senior debt securities will fully and unconditionally guarantee on an unsecured basis the full and prompt payment of the principal of and any premium and interest on the debt securities of that series when and as the payment becomes due and payable, whether at maturity or otherwise. As used in this prospectus, the term “Subsidiary Guarantors” with respect to a series of debt securities refers to those subsidiaries listed under “The Subsidiary Guarantors” that guarantee that series of debt securities. The applicable prospectus supplement will name the Subsidiary Guarantors, if any, for that series of debt securities and will describe the terms of the guarantee by the Subsidiary Guarantors if they differ from the terms described in this prospectus. The guarantees provide that in the event of a default in the payment of principal of or any premium or interest on a debt security, the holder of that debt security may institute legal proceedings directly against the Subsidiary Guarantors to enforce the guarantees without first proceeding against us. If senior debt securities are so guaranteed, the guarantees will rank equally with all of the Subsidiary Guarantors’ other unsecured and unsubordinated debt from time to time outstanding and senior to any subordinated debt of the Subsidiary Guarantors. If subordinated debt securities are so guaranteed, the guarantees will be subordinated to all of the Subsidiary Guarantors’ other unsecured and unsubordinated debt from time to time outstanding.

The obligations of each Subsidiary Guarantor under its guarantee of the debt securities will be limited to the maximum amount that will not result in the obligations of the Subsidiary Guarantor under the guarantee constituting a fraudulent conveyance or fraudulent transfer under federal or state law, after giving effect to:

• all other contingent and fixed liabilities of the Subsidiary Guarantor; and

• any collections from or payments made by or on behalf of any other Subsidiary Guarantors in respect of the obligations of the Subsidiary Guarantor under its guarantee.

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The guarantee of any Subsidiary Guarantor may be released under certain circumstances. If we exercise our legal or covenant defeasance option with respect to debt securities of a particular series as described below in “—Defeasance and Discharge,” then any Subsidiary Guarantor will be released with respect to that series. Further, if no default has occurred and is continuing under the applicable indenture, and to the extent not otherwise prohibited by the applicable indenture, a Subsidiary Guarantor will be unconditionally released and discharged from the guarantee:

• automatically upon any sale, exchange or transfer, whether by way of merger or otherwise, to any person that is not our affiliate, of all of our equity interests in the Subsidiary Guarantor;

• automatically upon the merger of the Subsidiary Guarantor into us or any other Subsidiary Guarantor or the liquidation and dissolution of the Subsidiary Guarantor; or

• following delivery of a written notice by us to the trustee, upon the release of all guarantees by the Subsidiary Guarantor of any debt of ours for borrowed money, except for any series of debt securities under the indenture.

Consolidation, Merger and Sales of Assets

The indentures generally permit a consolidation or merger involving us or the Subsidiary Guarantors. They also permit the Subsidiary Guarantors or us to sell, lease, convey, assign, transfer or otherwise dispose of all or substantially all of our assets. We and the Subsidiary Guarantors have agreed, however, that we will not consolidate with or merge into any entity or sell, lease, convey, assign, transfer or dispose of all or substantially all of our assets to any entity unless:

(1) either

• we or a Subsidiary Guarantor, as the case may be, are the continuing entity; or

• in the case of us, the resulting entity is organized under the laws of the United States, any state thereof, or the District of Columbia, and, in any case, the resulting entity assumes by a supplemental indenture the due and punctual payments on the debt securities and the performance of our covenants and obligations under the applicable indenture; and

(2) immediately after giving effect to the transaction, no default or event of default under the applicable indenture has occurred and is continuing or would result from the transaction.

This covenant will not apply to any merger of another entity into us. Upon any transaction of the type described in and effected in accordance with this section, the resulting entity will succeed to and be substituted for and may exercise all of our rights and powers under the indenture and the debt securities with the same effect as if the resulting entity had been named as us in the indenture. In the case of any asset transfer or disposition other than a lease, when the resulting entity assumes all of our obligations and covenants under the applicable indenture and the debt securities, we will be relieved of all such obligations.

Events of Default

Unless we inform you otherwise in the applicable prospectus supplement, the following are events of default with respect to a series of debt securities:

• our failure to pay interest on any debt security of that series for 30 days when due;

• our failure to pay principal of or any premium on any debt security of that series when due;

• our failure to deposit any sinking fund payment for 30 days when due;

• our failure to comply with any covenant or agreement in that series of debt securities or the applicable indenture (other than an agreement or covenant that has been included in the indenture solely for the

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benefit of other series of debt securities) for 60 days after written notice by the trustee or by the holders of at least 25% in principal amount of the outstanding debt securities issued under that indenture that are affected by that failure;

• specified events involving bankruptcy, insolvency or reorganization of Westlake Chemical Corporation or a Subsidiary Guarantor with respect to that series of debt securities that is a significant subsidiary (as defined in Regulation S-X promulgated by the SEC, as in effect on the date of the applicable indenture);

• if applicable, specified events involving the guarantees; and

• any other event of default provided for that series of debt securities.

A default under one series of debt securities will not necessarily be a default under any other series. If a default or event of default for any series of debt securities occurs, is continuing and is known to the trustee, the trustee will notify the holders of applicable debt securities within 90 days after it occurs. The trustee may withhold notice to the holders of the debt securities of any default or event of default, except in any payment on the debt securities, if the trustee in good faith determines that withholding notice is in the interests of the holders of those debt securities.

If an event of default for any series of debt securities occurs and is continuing, the trustee or the holders of at least 25% in principal amount of the outstanding debt securities of the series affected by the default (or, in some cases, 25% in principal amount of all debt securities issued under the applicable indenture that are affected, voting as one class) may declare the principal of and all accrued and unpaid interest on those debt securities to be due and payable immediately. If an event of default relating to certain events of bankruptcy, insolvency or reorganization of Westlake Chemical Corporation or a Subsidiary Guarantor that is a significant subsidiary occurs, the principal of and accrued and unpaid interest on all the debt securities of that series will become immediately due and payable without any action on the part of the trustee or any holder. At any time after a declaration of acceleration has been made, the holders of a majority in principal amount of the outstanding debt securities of the series affected by the default (or, in some cases, of all debt securities issued under the applicable indenture that are affected, voting as one class) may in some cases rescind this accelerated payment requirement and its consequences.

A holder of a debt security of any series issued under an indenture may pursue any remedy under that indenture only if:

• the holder gives the trustee written notice of a continuing event of default with respect to that series;

• the holders of at least 25% in principal amount of the outstanding debt securities of that series make a written request to the trustee to pursue the remedy;

• the holders offer to the trustee indemnity satisfactory to the trustee against any loss, liability or expense;

• the trustee does not comply with the request within 60 days after receipt of the request and offer of indemnity; and

• during that 60-day period, the holders of a majority in principal amount of the debt securities of that series do not give the trustee a direction inconsistent with the request.

This provision does not, however, affect the right of a holder of a debt security to sue for enforcement of any overdue payment.

In most cases, the trustee will be under no obligation to exercise any of its rights or powers under the indenture at the request or direction of any of the holders unless those holders have offered to the trustee indemnity satisfactory to it. Subject to this provision for indemnification, the holders of a majority in principal

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amount of the outstanding debt securities of a series (or of all debt securities issued under the applicable indenture that are affected, voting as one class) generally may direct the time, method and place of:

• conducting any proceeding for any remedy available to the trustee; or

• exercising any trust or power conferred on the trustee relating to or arising as a result of an event of default.

If an event of default occurs and is continuing, the trustee will be required to use the degree of care and skill of a prudent person in the conduct of his own affairs.

The indentures require us to furnish to the trustee annually a statement as to our performance of certain of our obligations under the indentures and as to any default in performance.

Modification and Waiver

We and the trustee may supplement or amend each indenture with the consent of the holders of at least a majority in principal amount of the outstanding debt securities of all series issued under that indenture that are affected by the amendment or supplement (voting as one class). Without the consent of the holder of each debt security affected, however, no modification may:

• reduce the amount of debt securities whose holders must consent to an amendment, supplement or waiver;

• reduce the rate of or change the time for payment of interest on the debt security;

• reduce the principal of the debt security or change its stated maturity;

• reduce any premium payable on the redemption of the debt security or change the time at which the debt security may or must be redeemed;

• change any obligation to pay additional amounts on the debt security;

• make payments on the debt security payable in currency other than as originally stated in the debt security;

• impair the holder’s right to institute suit for the enforcement of any payment on or with respect to the debt security;

• make any change in the percentage of principal amount of debt securities necessary to waive compliance with certain provisions of the indenture or to make any change in the provision related to modification;

• with respect to the subordinated indenture, modify the provisions relating to the subordination of any subordinated debt security in a manner adverse to the holder of that security;

• waive a continuing default or event of default regarding any payment on the debt securities; or

• if applicable, make any change that materially and adversely affects the right to convert any debt security.

We and the trustee may supplement or amend each indenture or waive any provision of that indenture without the consent of any holders of debt securities issued under that indenture in certain circumstances, including:

• to cure any ambiguity, omission, defect or inconsistency;

• to provide for the assumption of our obligations under the indenture by a successor upon any merger, consolidation or asset transfer permitted under the indenture;

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• to provide for uncertificated debt securities in addition to or in place of certificated debt securities or to provide for bearer debt securities;

• to provide any security for, or to add any guarantees of or obligors on, any series of debt securities;

• to comply with any requirement to effect or maintain the qualification of that indenture under the Trust Indenture Act of 1939;

• to add covenants that would benefit the holders of any debt securities or to surrender any rights we have under the indenture;

• to add events of default with respect to any series of debt securities;

• to make any change that does not adversely affect any outstanding debt securities of any series issued under that indenture in any material respect; and

• to establish the form or terms of any debt securities and to accept the appointment of a successor trustee, each as permitted under the indenture.

The holders of a majority in principal amount of the outstanding debt securities of any series (or, in some cases, of all debt securities issued under the applicable indenture that are affected, voting as one class) may waive any existing or past default or event of default with respect to those debt securities. Those holders may not, however, waive any default or event of default in any payment on any debt security or compliance with a provision that cannot be amended or supplemented without the consent of each holder affected.

Defeasance and Discharge

Defeasance. When we use the term defeasance, we mean discharge from some or all of our obligations under an indenture. If we deposit with the trustee under an indenture any combination of money or government securities sufficient to make payments on the debt securities of a series issued under that indenture on the dates those payments are due, then, at our option, either of the following will occur:

• we and the Subsidiary Guarantors, if applicable, will be discharged from our obligations with respect to the debt securities of that series (“legal defeasance”); or

• we and the Subsidiary Guarantors, if applicable, will no longer have any obligation to comply with specified restrictive covenants with respect to the debt securities of that series, the covenant described under “—Consolidation, Merger and Sales of Assets” and other specified covenants under the applicable indenture, and the related events of default will no longer apply (“covenant defeasance”).

If a series of debt securities is defeased, the holders of the debt securities of that series will not be entitled to the benefits of the applicable indenture, except for obligations to register the transfer or exchange of debt securities, replace stolen, lost or mutilated debt securities or maintain paying agencies and hold money for payment in trust. In the case of covenant defeasance, our obligation to pay principal, premium and interest on the debt securities, and if applicable, the Subsidiary Guarantors’ guarantees of the payments, will also survive.

Unless we inform you otherwise in the prospectus supplement, we will be required to deliver to the trustee an opinion of counsel that the deposit and related defeasance would not cause the holders of the debt securities to recognize income, gain or loss for U.S. federal income tax purposes and that the holders would be subject to U.S. federal income tax on the same amounts, in the same manner and at the same times as would have been the case if the deposit and related defeasance had not occurred. If we elect legal defeasance, that opinion of counsel must be based upon a ruling from the United States Internal Revenue Service or a change in law to that effect.

Under current U.S. federal income tax law, legal defeasance would likely be treated as a taxable exchange of debt securities to be defeased for interests in the defeasance trust. As a consequence, a United States holder would recognize gain or loss equal to the difference between the holder’s cost or other tax basis for the debt

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securities and the value of the holder’s interest in the defeasance trust, and thereafter would be required to include in income a share of the income, gain or loss of the defeasance trust. Under current U.S. federal income tax law, covenant defeasance would not be treated as a taxable exchange of such debt securities.

Satisfaction and Discharge. In addition, an indenture will cease to be of further effect with respect to the debt securities of a series issued under that indenture, subject to exceptions relating to compensation and indemnity of the trustee under that indenture and repayment to us of excess money or government securities, when:

• either

(a) all outstanding debt securities of that series have been delivered to the trustee for cancellation; or

(b) all outstanding debt securities of that series not delivered to the trustee for cancellation either:

• have become due and payable,

• will become due and payable at their stated maturity within one year, or

• are to be called for redemption within one year; and

• we have deposited with the trustee any combination of money or government securities in trust sufficient to pay the entire indebtedness on the debt securities of that series when due; and

• we have paid all other sums payable by us with respect to the debt securities of that series.

Governing Law

New York law will govern the indentures, the debt securities and the guarantees.

The Trustees

The Bank of New York Mellon Trust Company, N.A. (successor to JPMorgan Chase Bank, National Association) acts as the trustee under our senior indenture. Unless we inform you otherwise in a prospectus supplement, The Bank of New York Mellon Trust Company, N.A. will act as the trustee with respect the senior debt securities described in such prospectus supplement. We will name the trustee under a subordinated indenture in the applicable prospectus supplement.

Each indenture contains limitations on the right of the trustee, if it or any of its affiliates is then our creditor or, if applicable, a creditor of a Subsidiary Guarantors, to obtain payment of claims or to realize on certain property received for any such claim, as security or otherwise. The trustee and its affiliates are permitted to engage in other transactions with us, and, if applicable, the Subsidiary Guarantors. If, however, the trustee acquires any conflicting interest, it must eliminate that conflict or resign within 90 days after ascertaining that it has a conflicting interest and after the occurrence of a default under the applicable indenture, unless the default has been cured, waived or otherwise eliminated within the 90-day period.

Payments and Paying Agents

Unless we inform you otherwise in a prospectus supplement, we will make payments on the debt securities in U.S. dollars at the office of the trustee and any paying agent. At our option, however, payments may be made by wire transfer for global debt securities or by check mailed to the address of the person entitled to the payment as it appears in the security register. Unless we inform you otherwise in a prospectus supplement, we will make interest payments to the person in whose name the debt security is registered at the close of business on the record date for the interest payment.

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Unless we inform you otherwise in a prospectus supplement, the trustee under the applicable indenture will be designated as the paying agent for payments on debt securities issued under that indenture. We may at any time designate additional paying agents or rescind the designation of any paying agent or approve a change in the office through which any paying agent acts.

If the principal of or any premium or interest on debt securities of a series is payable on a day that is not a business day, the payment will be made on the following business day. For these purposes, unless we inform you otherwise in a prospectus supplement, a “business day” is any day that is not a Saturday, a Sunday or a day on which banking institutions in any of New York, New York, Houston, Texas or a place of payment on the debt securities of that series is authorized or obligated by law, regulation or executive order to remain closed.

Subject to the requirements of any applicable abandoned property laws, the trustee and paying agent will pay to us upon written request any money held by them for payments on the debt securities that remains unclaimed for two years after the date upon which that payment has become due. After payment to us, holders entitled to the money must look to us for payment. In that case, all liability of the trustee or paying agent with respect to that money will cease.

Form, Exchange, Registration and Transfer

We will issue the debt securities in registered form, without interest coupons. Debt securities of any series will be exchangeable for other debt securities of the same series, the same total principal amount and the same terms but in different authorized denominations in accordance with the applicable indenture. Holders may present debt securities for registration of transfer at the office of the security registrar or any transfer agent designated by us. The security registrar or transfer agent will effect the transfer or exchange if its requirements and the requirements of the applicable indenture are met. We will not charge a service charge for any registration of transfer or exchange of the debt securities. We may, however, require payment of any transfer tax or similar governmental charge payable for that registration.

We will appoint the trustee as security registrar for the debt securities. If a prospectus supplement refers to any transfer agents we initially designate, we may at any time rescind that designation or approve a change in the location through which any transfer agent acts. We are required to maintain an office or agency for transfers and exchanges in each place of payment. We may at any time designate additional transfer agents for any series of debt securities.

In the case of any redemption of debt securities of a series or any repurchase of debt securities of a series required under the terms of the series, we will not be required to register the transfer or exchange of:

• any debt security of that series 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 of such notice; or

• any debt security of that series that has been called for redemption in whole or in part, except the unredeemed portion of any debt security being redeemed in part.

Book-Entry Debt Securities

We may issue the debt securities of a series in the form of one or more global debt securities that would be deposited with a depositary or its nominee identified in the prospectus supplement. We may issue global debt securities in either temporary or permanent form. We will describe in the prospectus supplement the terms of any depositary arrangement and the rights and limitations of owners of beneficial interests in any global debt security.

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DESCRIPTION OF CAPITAL STOCK

General

The following descriptions are summaries of material terms of our common stock, preferred stock, amended and restated certificate of incorporation and amended and restated bylaws. Copies of our amended and restated certificate of incorporation and amended and restated bylaws have been incorporated by reference as exhibits to the registration statement of which this prospectus is a part, and you are urged to review these documents. Please read “Where You Can Find More Information.”

As of the date of this prospectus, our authorized capital stock consists of 150 million shares of common stock, par value $0.01 per share, and 50 million shares of preferred stock, par value $0.01 per share.

Common Stock

Each share of common stock entitles the holder to one vote on all matters on which holders are permitted to vote, including the election of directors. There are no cumulative voting rights. Accordingly, holders of a majority of the total votes entitled to vote in an election of directors will be able to elect all of the directors standing for election. Subject to preferences that may be applicable to any outstanding preferred stock, the holders of the common stock will share equally on a per share basis any dividends when, as and if declared by the board of directors out of funds legally available for that purpose. If we are liquidated, dissolved or wound up, the holders of our common stock will be entitled to a ratable share of any distribution to stockholders, after satisfaction of all of our liabilities and of the prior rights of any outstanding class of our preferred stock. Our common stock has no preemptive or conversion rights or other subscription rights. There are no redemption or sinking fund provisions applicable to our common stock. All outstanding shares of our common stock are fully paid and nonassessable.

Preferred Stock

Our board of directors has the authority, without stockholder approval, to issue shares of preferred stock from time to time in one or more series, and to fix the number of shares and terms of each such series. The board may determine the designation and other terms of each series, including the following:

• dividend rates,

• whether dividends will be cumulative or non-cumulative,

• redemption rights,

• liquidation rights,

• sinking fund provisions,

• conversion or exchange rights, and

• voting rights.

The issuance of preferred stock, while providing us with flexibility in connection with possible acquisitions and other transactions, could adversely affect the voting power of holders of our common stock. It could also affect the likelihood that holders of our common stock will receive dividend payments and payments upon liquidation.

The issuance of shares of preferred stock, or the issuance of rights to purchase shares of preferred stock, could be used to discourage an attempt to obtain control of our company. For example, if, in the exercise of its fiduciary obligations, our board of directors were to determine that a takeover proposal was not in the best interest of our stockholders, the board could authorize the issuance of a series of preferred stock containing class voting rights that would enable the holder or holders of this series to prevent a change of control transaction or

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make it more difficult. Alternatively, a change of control transaction deemed by the board to be in the best interest of our stockholders could be facilitated by issuing a series of preferred stock having sufficient voting rights to provide a required percentage vote of the stockholders.

The prospectus supplement relating to any series of preferred stock that we may offer will include specific terms relating to the offering. We will file a form of certificate of designation with the SEC, and you should read the certificate of designation for provisions that may be important to you. The prospectus supplement will summarize the general terms of any such series of preferred stock.

Charter and Bylaw Provisions

Election and Removal of Directors

Our board of directors consists of between one and 11 directors, excluding any directors elected by holders of preferred stock pursuant to provisions applicable in the case of defaults. The exact number of directors will be fixed from time to time by resolution of the board. Our board of directors is divided into three classes serving staggered three-year terms, with only one class being elected each year by our stockholders. At each annual meeting of stockholders, directors will be elected to succeed the class of directors whose terms have expired. This system of electing and removing directors may discourage a third party from making a tender offer or otherwise attempting to obtain control of us, because it generally makes it more difficult for stockholders to replace a majority of the directors. In addition, no director may be removed except for cause, and directors may be removed for cause by an affirmative vote of shares representing a majority of the shares then entitled to vote at an election of directors. Any vacancy occurring on the board of directors and any newly created directorship may only be filled by a majority of the remaining directors in office.

Stockholder Meetings

Our amended and restated certificate of incorporation and our amended and restated bylaws provide that special meetings of our stockholders may be called only by the chairman of our board of directors or a majority of the directors. Our amended and restated certificate of incorporation and our amended and restated bylaws specifically deny any power of any other person to call a special meeting.

Stockholder Action by Written Consent

Our amended and restated certificate of incorporation and our amended and restated bylaws provide that holders of our common stock will not be able to act by written consent without a meeting, unless such consent is unanimous.

Amendment of Certificate of Incorporation

The provisions of our amended and restated certificate of incorporation described above under “—Election and Removal of Directors,” “—Stockholder Meetings” and “—Stockholder Action by Written Consent” may be amended only by the affirmative vote of holders of at least 75% of the voting power of our outstanding shares of voting stock, voting together as a single class. The affirmative vote of holders of at least a majority of the voting power of our outstanding shares of stock is generally required to amend other provisions of our amended and restated certificate of incorporation.

Amendment of Bylaws

Our amended and restated bylaws may generally be altered, amended or repealed, and new bylaws may be adopted, with:

• the affirmative vote of a majority of directors present at any regular or special meeting of the board of directors called for that purpose, provided that any alteration, amendment or repeal of, or adoption of any bylaw inconsistent with specified provisions of the bylaws, including those related to special and

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annual meetings of stockholders, action of stockholders by written consent, classification of the board of directors, nomination of directors, special meetings of directors, removal of directors, committees of the board of directors and indemnification of directors and officers, requires the affirmative vote of at least 75% of all directors in office at a meeting called for that purpose, or

• the affirmative vote of holders of 75% of the voting power of our outstanding shares of voting stock, voting together as a single class.

Other Limitations on Stockholder Actions

Our amended and restated bylaws also impose some procedural requirements on stockholders who wish to:

• make nominations in the election of directors,

• propose that a director be removed,

• propose any repeal or change in our bylaws, or

• propose any other business to be brought before an annual or special meeting of stockholders.

Under these procedural requirements, in order to bring a proposal before a meeting of stockholders, a stockholder must deliver timely notice of a proposal pertaining to a proper subject for presentation at the meeting to our corporate secretary along with the following:

• a description of the business or nomination to be brought before the meeting and the reasons for conducting such business at the meeting,

• the stockholder’s name and address,

• the number of shares beneficially owned by the stockholder and evidence of such ownership, and

• the names and addresses of all persons with whom the stockholder is acting in concert and a description of all arrangements and understandings with those persons, and the number of shares such persons beneficially own.

To be timely, a stockholder must generally deliver notice:

• in connection with an annual meeting of stockholders, not less than 120 nor more than 180 days prior to the date on which the annual meeting of stockholders was held in the immediately preceding year, but in the event that the date of the annual meeting is more than 30 days before or more than 60 days after the anniversary date of the preceding annual meeting of stockholders, a stockholder notice will be timely if received by us not later than the close of business on the later of (1) the 120th day prior to the annual meeting and (2) the 10th day following the day on which we first publicly announce the date of the annual meeting, or

• in connection with the election of a director at a special meeting of stockholders, not less than 40 nor more than 60 days prior to the date of the special meeting, but in the event that less than 55 days’ notice or prior public disclosure of the date of the special meeting of the stockholders is given or made to the stockholders, a stockholder notice will be timely if received by us not later than the close of business on the 10th day following the day on which a notice of the date of the special meeting was mailed to the stockholders or the public disclosure of that date was made.

In order to submit a nomination for our board of directors, a stockholder must also submit any information with respect to the nominee that we would be required to include in a proxy statement, as well as some other information. If a stockholder fails to follow the required procedures, the stockholder’s proposal or nominee will be ineligible and will not be voted on by our stockholders.

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Limitation on Liability of Directors

Our amended and restated certificate of incorporation provides that no director will be personally liable to us or our stockholders for monetary damages for breach of fiduciary duties as a director, except as required by applicable law, as in effect from time to time. Currently, Delaware law requires that liability be imposed for the following:

• any breach of the director’s duty of loyalty to our company or our stockholders,

• any act or omission not in good faith or which involved intentional misconduct or a knowing violation of law,

• unlawful payments of dividends or unlawful stock repurchases or redemptions as provided in Section 174 of the Delaware General Corporation Law, and

• any transaction from which the director derived an improper personal benefit.

Our amended and restated bylaws provide that, to the fullest extent permitted by law, we will indemnify any officer or director of our company against all damages, claims and liabilities arising out of the fact that the person is or was our director or officer, or served any other enterprise at our request as a director, officer, employee, agent or fiduciary. We will reimburse the expenses, including attorneys’ fees, incurred by a person indemnified by this provision when we receive an undertaking to repay such amounts if it is ultimately determined that the person is not entitled to be indemnified by us. Amending this provision will not reduce our indemnification obligations relating to actions taken before an amendment.

Anti-Takeover Effects of Some Provisions

Some provisions of our amended and restated certificate of incorporation and amended and restated bylaws could make the following more difficult:

• acquisition of control of us by means of a proxy contest or otherwise, or

• removal of our incumbent officers and directors.

These provisions, as well as our ability to issue preferred stock, are designed to discourage coercive takeover practices and inadequate takeover bids. These provisions are also designed to encourage persons seeking to acquire control of us to first negotiate with our board of directors. We believe that the benefits of increased protection give us the potential ability to negotiate with the proponent of an unfriendly or unsolicited proposal to acquire or restructure us, and that the benefits of this increased protection outweigh the disadvantages of discouraging those proposals, because negotiation of those proposals could result in an improvement of their terms.

Transactions and Corporate Opportunities

Our amended and restated certificate of incorporation includes provisions that regulate and define the conduct of specified aspects of the business and affairs of our company. These provisions serve to determine and delineate the respective rights and duties of our company, our principal stockholder, TTWF LP, and its direct and indirect equity owners and directors, officers, employees, partners or equity owners of such entities (the “principal stockholder affiliates”), and some of our directors and officers in anticipation of the following:

• the principal stockholder affiliates serving as our directors and/or officers,

• the principal stockholder affiliates engaging in lines of business that are the same as, or similar to, our lines of business,

• the principal stockholder affiliates having an interest in the same areas of corporate opportunity as we have, and

• we and the principal stockholder affiliates engaging in material business transactions.

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We may enter into agreements with the principal stockholder affiliates to engage in any transaction. We may also enter into agreements with the principal stockholder affiliates to compete or not to compete with each other, including agreements to allocate, or to cause our directors, officers and employees and the principal stockholder affiliates to allocate, opportunities between the principal stockholder affiliates and us. Our amended and restated certificate of incorporation provides that no such agreement will be considered contrary to any fiduciary duty of the principal stockholder affiliates, as our direct and indirect controlling stockholders, or our directors, officers or employees. Neither the principal stockholder affiliates nor any of our directors, officers or employees who are also principal stockholder affiliates are under any fiduciary duty to us to refrain from acting on our behalf or on behalf of the principal stockholder affiliates in respect of any such agreement or transaction. These provisions are generally subject to the corporate opportunity obligations described below with which the principal stockholder affiliates and our officers and directors who are also principal stockholder affiliates must comply.

Under our amended and restated certificate of incorporation, the principal stockholder affiliates have no duty to refrain from engaging in activities or lines of business similar to ours or from doing business with any of our clients, customers or vendors and, except as discussed in the above paragraph, the principal stockholder affiliates will not be liable to us or our stockholders for breach of any fiduciary duty as a stockholder by reason of any of these activities. In addition, if the principal stockholder affiliates or one of our directors or officers who is also a principal stockholder affiliate acquires knowledge of a potential transaction or matter which may be a corporate opportunity for both our company and the principal stockholder affiliates, then neither the principal stockholder affiliates nor any such person will have a duty to communicate or offer this corporate opportunity to us and will not be liable to us or our stockholders for breach of any fiduciary duty by reason of the fact that the principal stockholder affiliates pursue or acquire the corporate opportunity for themselves, direct the corporate opportunity to another person or do not communicate information regarding the corporate opportunity to us, so long as the principal stockholder affiliates act in a manner consistent with the following policy: A corporate opportunity offered to the principal stockholder affiliates or to any person who is one of our officers or directors and who is also a principal stockholder affiliate will belong to the principal stockholder affiliates, unless the opportunity was expressly offered in writing to the principal stockholder affiliates solely in their capacity as direct and indirect stockholders of our company or to that person solely in his or her capacity as one of our directors or officers.

Anyone becoming one of our stockholders will be deemed to have notice of and consented to these provisions of our amended and restated certificate of incorporation. Our amended and restated certificate of incorporation provides that in no event shall any amendment of these provisions subject any principal stockholder affiliate to liability for any act or omission occurring prior to such amendment for which such person would be deemed not to be liable under these provisions prior to such amendment.

Delaware Business Combination Statute

We have expressly elected not to be subject to Section 203 of the General Corporation Law of the State of Delaware, which is described below. However, our stockholders can amend our amended and restated certificate of incorporation and amended and restated bylaws to elect to be subject to Section 203. Section 203 provides that, subject to specified exceptions, an interested stockholder of a Delaware corporation is not permitted to engage in any business combination, including mergers or consolidations or acquisitions of additional shares of the corporation, with the corporation for a three-year period following the time that stockholder became an interested stockholder, unless one of the following conditions is met:

• prior to the time the stockholder became an interested stockholder, the board of directors approved either the business combination or the transaction that resulted in the stockholder’s becoming an interested stockholder,

• upon consummation of the transaction that resulted in the stockholder’s becoming an interested stockholder, the interested stockholder owned at least 85% of the voting stock of the corporation outstanding at the time the transaction commenced, other than statutorily excluded shares, or

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• on or subsequent to the time the stockholder became an interested stockholder, the business combination is approved by the board of directors and authorized at an annual or special meeting of stockholders by the affirmative vote of at least 66 ²/3% of the outstanding voting stock which is not owned by the interested stockholder.

Except as otherwise set forth in Section 203, “interested stockholder” means:

• any person that is the owner of 15% or more of the outstanding voting stock of the corporation, or is an affiliate or associate of the corporation and was the owner of 15% or more of the outstanding voting stock of the corporation at any time within three years immediately prior to the date of determination, and

• the affiliates and associates of any such person.

If we ever become subject to Section 203, it may be more difficult for a person who is an interested stockholder to effect various business combinations with us for the applicable three-year period. Section 203, if it becomes applicable, also may have the effect of preventing changes in our management. It is possible that Section 203, if it becomes applicable, could make it more difficult to accomplish transactions which our stockholders may otherwise deem to be in their best interests. The provisions of Section 203, if it becomes applicable, may cause persons interested in acquiring us to negotiate in advance with our board of directors. The restrictions on business combinations set forth in Section 203 are not applicable to the principal stockholder so long as the principal stockholder holds 15% or more of our outstanding shares of common stock. Because we are not currently subject to Section 203, the principal stockholder, as a controlling stockholder, may find it easier to sell its controlling interest to a third party because Section 203 would not apply to the third party.

Listing of Common Stock

Our common stock is listed on the New York Stock Exchange under the symbol “WLK.”

Transfer Agent and Registrar

The transfer agent and registrar for our common stock is American Stock Transfer & Trust Company.

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DESCRIPTION OF WARRANTS

We may issue warrants to purchase debt securities, common stock, preferred stock or other securities or any combination of the foregoing. We may issue warrants independently or together with other securities. Warrants sold with other securities may be attached to or separate from the other securities. We will issue warrants under one or more warrant agreements between us and a warrant agent that we will name in the prospectus supplement.

The prospectus supplement relating to any warrants that we may offer will include specific terms relating to the offering. We will file the form of any warrant agreement with the SEC, and you should read the warrant agreement for provisions that may be important to you. The prospectus supplement will include some or all of the following terms:

• the title of the warrants;

• the aggregate number of warrants offered;

• the designation, number and terms of the debt securities, common stock, preferred stock or other securities purchasable upon exercise of the warrants, and procedures by which those numbers may be adjusted;

• the exercise price of the warrants;

• the dates or periods during which the warrants are exercisable;

• the designation and terms of any securities with which the warrants are issued;

• if the warrants are issued as a unit with another security, the date, if any, on and after which the warrants and the other security will be separately transferable;

• if the exercise price is not payable in U.S. dollars, the foreign currency, currency unit or composite currency in which the exercise price is denominated;

• any minimum or maximum amount of warrants that may be exercised at any one time; and

• any terms, procedures and limitations relating to the transferability, exchange or exercise of the warrants.

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SELLING STOCKHOLDER

In addition to covering the issuance and sale of securities by us, this prospectus covers the possible sale from time to time of up to 4,500,000 shares of our common stock by the selling stockholder listed below. As used in this prospectus, “selling stockholder” includes the successors-in-interest, donees, transferees or others who may later hold the selling stockholder’s interests and who will be named in a supplement to this prospectus.

The following table sets forth information as of April 1, 2011 regarding the beneficial ownership of the common stock held by the selling stockholder. Since the selling stockholder may sell none, all, or a portion of the 4,500,000 shares of our common stock included in the prospectus, no meaningful estimate can be given as to the amount or percentage of shares that will be held by the selling stockholder after completion of any sale by the selling stockholder.

Name and Address	Number of Shares	Percent of Stock (1)
TTWF LP (2) (3)	46,005,277	69.1%

(1) Calculated as of September 26, 2011 based on 66,605,181 shares of common stock outstanding.

(2) The address of the selling stockholder is 2801 Post Oak Boulevard, Houston, Texas 77056. The selling stockholder may be deemed an “underwriter” within the meaning of the Securities Act of 1933, as amended (the “Securities Act”), with respect to sales of the shares listed above.

(3) Two trusts for the benefit of members of the Chao family, including James Chao, our Chairman of the Board of Directors, Dorothy C. Jenkins, a director, and Albert Chao, our President and Chief Executive Officer and a director, are the managers of TTWFGP LLC, a Delaware limited liability company, which is the general partner of TTWF LP. The limited partners of TTWF LP are five trusts principally for the benefit of members of the Chao family, including James Chao, Dorothy C. Jenkins and Albert Chao and two corporations owned, indirectly or directly, by certain of these trusts and by other entities owned by members of the Chao family, including James Chao, Dorothy C. Jenkins and Albert Chao. TTWF LP and TTWFGP LLC each have shared voting power and shared dispositive power over 46,005,277 shares of our common stock. As of April 1, 2011, James Chao had sole voting power and sole dispositive power over 149,931 shares of our common stock, sole voting and no dispositive power over 67,966 shares of our common stock, and shared voting power and shared dispositive power over 46,005,277 shares of our common stock. Dorothy C. Jenkins had sole voting power and sole dispositive power over 17,404 shares of our common stock, sole voting power and no dispositive power over 4,164 shares of our common stock, and shared voting power and shared dispositive power over 46,005,277 shares of our common stock. Albert Chao had sole voting power and sole dispositive power over 310,309 shares of our common stock, sole voting and no dispositive power over 90,701 shares of our common stock and shared voting power and shared dispositive power over 46,005,277 shares of our common stock. James Chao, Dorothy C. Jenkins and Albert Chao disclaim beneficial ownership of the 46,005,277 shares of our common stock held by TTWF LP except to the extent of their respective pecuniary interest therein.

Registration Rights Agreement

We are party to a registration rights agreement with the selling stockholder under which we have agreed, at the request of the selling stockholder, to use our best efforts to register shares of our common stock that are held by the selling stockholder for public sale under the Securities Act. As long as the selling stockholder owns a majority of the voting power of our outstanding common stock, there is no limit to the number of registrations that it may request. Once the selling stockholder owns less than a majority of the voting power of our outstanding common stock, it can request a total of five additional registrations. We have also agreed to provide the selling stockholder and its permitted transferees with “piggy-back” rights to include its shares in registrations of our common stock under the Securities Act. There is no limit on the number of these “piggy-back” registrations in which the selling stockholder may request its shares be included. These rights will terminate once the selling stockholder is able to dispose of all of its shares of our common stock within a three-month period pursuant to

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the exemption from registration provided under Rule 144 of the Securities Act. We have agreed to cooperate in these registrations and related offerings. We and the selling stockholder have agreed to restrictions on the ability of each party to sell securities following registrations requested by either party. The shares that may be sold by the selling stockholder hereunder are included in this prospectus pursuant to the registration rights agreement.

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PLAN OF DISTRIBUTION

We and the selling stockholder may sell the securities in and outside the United States (a) through underwriters or dealers, (b) directly to purchasers or (c) through agents. The prospectus supplement will include the following information:

• the terms of the offering;

• the names of any underwriters or agents;

• the purchase price of the securities from us or the selling stockholder and, if the purchase price is not payable in U.S. dollars, the currency or composite currency in which the purchase price is payable;

• the net proceeds to us or the selling stockholder from the sale of securities;

• any delayed delivery arrangements;

• any underwriting discounts, commissions and other items constituting underwriters’ compensation;

• the initial public offering price;

• any discounts or concessions allowed or reallowed or paid to dealers; and

• any commissions paid to agents.

Sale Through Underwriters or Dealers

If we or the selling stockholder use underwriters in the sale of securities, the underwriters will acquire the securities for their own account. The underwriters may resell the securities from time to time in one or more transactions, including negotiated transactions, at a fixed public offering price or at varying prices determined at the time of sale. Underwriters may offer securities to the public either through underwriting syndicates represented by one or more managing underwriters or directly by one or more firms acting as underwriters. Unless we inform you otherwise in the prospectus supplement, the obligations of the underwriters to purchase the securities will be subject to conditions, and the underwriters will be obligated to purchase all the offered securities if they purchase any of them. The underwriters may change from time to time any initial public offering price and any discounts or concessions allowed or reallowed or paid to dealers.

During and after an offering through underwriters, the underwriters may purchase and sell the securities in the open market. These transactions may include overallotment and stabilizing transactions and purchases to cover syndicate short positions created in connection with the offering. The underwriters also may impose a penalty bid, which means that selling concessions allowed to syndicate members or other broker-dealers for the offered securities sold for their account may be reclaimed by the syndicate if the offered securities are repurchased by the syndicate in stabilizing or covering transactions. These activities may stabilize, maintain or otherwise affect the market price of the offered securities, which may be higher than the price that might otherwise prevail in the open market. If commenced, the underwriters may discontinue these activities at any time.

If we or the selling stockholder use dealers in the sale of securities, the securities will be sold directly to them as principals. They may then resell those securities to the public at varying prices determined by the dealers at the time of resale. The dealers participating in any sale of the securities may be deemed to be underwriters within the meaning of the Securities Act with respect to any sale of those securities. We will include in the prospectus supplement the names of the dealers and the terms of the transaction.

Direct Sales and Sales Through Agents

We or the selling stockholder may sell the securities directly. In that event, no underwriters or agents would be involved. We or the selling stockholder may also sell the securities through agents designated from time to time. In the prospectus supplement, we will name any agent involved in the offer or sale of the offered securities,

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and we will describe any commissions payable by us or the selling stockholder to the agent. Unless we inform you otherwise in the prospectus supplement, any agent will agree to use its reasonable best efforts to solicit purchases for the period of its appointment.

We or the selling stockholder may sell the securities directly to institutional investors or others who may be deemed to be underwriters within the meaning of the Securities Act with respect to any sale of those securities. We or the selling stockholder will describe the terms of any such sales in the prospectus supplement.

Private Sales

The shares of our common stock covered by this prospectus that may be sold by the selling stockholder qualify for sale pursuant to Rule 144 under the Securities Act and may be sold by the selling stockholder under Rule 144 rather than pursuant to this prospectus.

Delayed Delivery Contracts

If we so indicate in the prospectus supplement, we or the selling stockholder may authorize agents, underwriters or dealers to solicit offers from certain types of institutions to purchase securities from us at the public offering price under delayed delivery contracts. These contracts would provide for payment and delivery on a specified date in the future. The contracts would be subject only to those conditions described in the prospectus supplement. The prospectus supplement will describe the commission payable for solicitation of those contracts.

Remarketing

We may offer and sell any of the securities in connection with a remarketing upon their purchase, in accordance with a redemption or repayment by their terms or otherwise, by one or more remarketing firms acting as principals for their own accounts or as our agents. We will identify any remarketing firm, the terms of any remarketing agreement and the compensation to be paid to the remarketing firm in the prospectus supplement. Remarketing firms may be deemed underwriters under the Securities Act.

Derivative Transactions

We or the selling stockholder may enter into derivative transactions with third parties, or sell securities not covered by this prospectus to third parties in privately negotiated transactions. If the applicable prospectus supplement indicates, in connection with those derivatives, the third parties may sell securities covered by this prospectus and the applicable prospectus supplement, including in short sale transactions. If so, the third parties may use securities pledged by us or borrowed from us or others to settle those sales or to close out any related open borrowings of stock, and may use securities received from us in settlement of those derivatives to close out any related open borrowings of stock.

We, the selling stockholder or one of our respective affiliates may loan or pledge securities to a financial institution or other third party that in turn may sell the securities using this prospectus. Such financial institution or third party may transfer its short position to investors in our securities or in connection with a simultaneous offering of other securities offered by this prospectus or otherwise.

The third parties in any of the sale transactions described above will be underwriters and will be identified in the applicable prospectus supplement or in a post-effective amendment to the registration statement of which this prospectus forms a part.

General Information

We or the selling stockholder may have agreements with the agents, dealers and underwriters to indemnify them against certain civil liabilities, including liabilities under the Securities Act, or to contribute with respect to

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payments that the agents, dealers or underwriters may be required to make. Agents, dealers and underwriters may be customers of, engage in transactions with or perform services for us in the ordinary course of their businesses.

Pursuant to the registration rights agreement described under “Selling Stockholder,” we have agreed to pay all of the costs, fees and expenses incurred by us incident to our registration of the resale of the selling stockholder’s common stock, as well as legal fees and expenses of counsel to the selling stockholder. We will not pay any commissions, fees and discounts of underwriters, brokers, dealers and agents with respect to shares of our common stock sold by the selling stockholder.

LEGAL OPINIONS

Certain legal matters in connection with this offering will be passed upon for us by Baker Botts L.L.P., Houston, Texas. Any underwriters will be advised about other issues relating to any offering by their own legal counsel, which firm will be named in the related prospectus supplement.

EXPERTS

The financial statements and management’s assessment of the effectiveness of internal control over financial reporting (which is included in Management’s Report on Internal Control over Financial Reporting) incorporated in this prospectus by reference to our Annual Report on Form 10-K for the year ended December 31, 2010 have been so incorporated in reliance on the report of PricewaterhouseCoopers LLP, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting.

WHERE YOU CAN FIND MORE INFORMATION

We file reports, proxy statements and other information with the SEC. You can read and copy any materials we file with the SEC at the SEC’s public reference room at 100 F Street, N.E., Room 1850, Washington, D.C. 20549. You can obtain information about the operation of the SEC’s public reference room by calling the SEC at 1-800-SEC-0330. The SEC also maintains a Web site that contains information we file electronically with the SEC, which you can access over the Internet at http://www.sec.gov. You can obtain information about us at the offices of the New York Stock Exchange, 20 Broad Street, New York, New York 10005.

Our Web site is located at http: //www.westlake.com. Our Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and other filings with the SEC are available, free of charge, through our Web site, as soon as reasonably practicable after those reports or filings are electronically filed with or furnished to the SEC. Information on our Web site or any other website is not incorporated by reference in this prospectus and does not constitute a part of this prospectus.

This prospectus is part of a registration statement we have filed with the SEC relating to the securities we and the selling stockholder may sell. As permitted by SEC rules, this prospectus does not contain all of the information we have included in the registration statement and the accompanying exhibits and schedules we file with the SEC. You may refer to the registration statement, the exhibits and the schedules for more information about us, the selling stockholder and our securities. The registration statement, exhibits and schedules are available at the SEC’s public reference room or through its Web site.

We are incorporating by reference information we file with the SEC, which means that we are disclosing important information to you by referring you to those documents. The information we incorporate by reference is an important part of this prospectus, and later information that we file with the SEC automatically will update

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and supersede this information. We incorporate by reference the documents listed below and any future filings we make with the SEC under Section 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), until we sell all the securities:

• our annual report on Form 10-K for the fiscal year ended December 31, 2010;

• our quarterly reports on Form 10-Q for the quarters ended March 31, 2011 and June 30, 2011;

• our current reports on Form 8-K filed with the SEC on May 25, 2011, September 19, 2011; and

• the description of our common stock contained in our Registration Statement on Form 8-A filed with the SEC on July 30, 2004, as we may update that description from time to time.

We also are incorporating by reference all additional documents that we may file with the SEC under Section 13(a), 13(c), 14 or 15(d) of the Exchange Act after the date hereof and prior to the effectiveness of the registration statement.

You may request a copy of these filings (other than an exhibit to those filings unless we have specifically incorporated that exhibit by reference into the filing), at no cost, by writing or telephoning us at the following address:

Westlake Chemical Corporation

2801 Post Oak Boulevard, Suite 600

Houston, Texas 77056

Attention: Investor Relations

Telephone: (713) 960-9111

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$250,000,000

            % Senior Notes due 2022

Prospectus    Supplement

July     , 2012

BofA Merrill Lynch

Deutsche Bank Securities

Morgan Stanley