10-Q

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form 10-Q

x	QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
	For the quarterly period ended September 30, 2013

or

¨	TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
	For the Transition Period from                    to

Commission File No. 001-32260

Westlake Chemical Corporation

(Exact name of Registrant as specified in its charter)

Delaware	76-0346924
(State or other jurisdiction of incorporation or organization)	(I.R.S. Employer Identification Number)

2801 Post Oak Boulevard, Suite 600

Houston, Texas 77056

(Address of principal executive offices, including zip code)

(713) 960-9111

(Registrant's telephone number, including area code)

Indicate by check mark whether the registrant: (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.     YesxNo¨

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).     YesxNo¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, or a smaller reporting company. See definitions of "large accelerated filer," "accelerated filer" and "smaller reporting company" in Rule 12b-2 of the Exchange Act (Check one):

Large accelerated filer	x	Accelerated filer	¨
Non-accelerated filer	¨  (Do not check if a smaller reporting company)	Smaller reporting company	¨

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act)     Yes¨Nox

The number of shares outstanding of the registrant's sole class of common stock as of November 1, 2013 was 66,770,803.

INDEX

Item	Page
PART I. FINANCIAL INFORMATION
1) Financial Statements	1
2) Management's Discussion and Analysis of Financial Condition and Results of Operations	24
3) Quantitative and Qualitative Disclosures about Market Risk	33
4) Controls and Procedures	34
PART II. OTHER INFORMATION
1) Legal Proceedings	35
1A) Risk Factors	35
2) Unregistered Sales of Equity Securities and Use of Proceeds	35
6) Exhibits	36

PART I. FINANCIAL INFORMATION

Item 1. Financial Statements

WESTLAKE CHEMICAL CORPORATION

CONSOLIDATED BALANCE SHEETS

(Unaudited)

	September 30, 2013			December 31, 2012
	(in thousands of dollars, except par values and share amounts)
ASSETS
Current assets
Cash and cash equivalents	$	591,556		$	790,078
Marketable securities	125,597			124,873
Accounts receivable, net	433,025			400,159
Inventories	451,571			399,298
Prepaid expenses and other current assets	18,809			14,700
Deferred income taxes	22,293			22,305
Total current assets	1,642,851			1,751,413
Property, plant and equipment, net	1,952,918			1,510,048
Equity investments	65,488			43,736
Other assets, net
Intangible assets, net	159,376			48,292
Deferred charges and other assets, net	102,816			58,707
Total other assets, net	262,192			106,999
Total assets	$	3,923,449		$	3,412,196
LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities
Accounts payable	$	258,067		$	217,050
Accrued liabilities	174,619			181,460
Total current liabilities	432,686			398,510
Long-term debt	763,849			763,761
Deferred income taxes	410,166			326,290
Other liabilities	51,691			51,379
Total liabilities	1,658,392			1,539,940
Commitments and contingencies (Notes 7 and 16)
Stockholders' equity
Preferred stock, $0.01 par value, 50,000,000 shares authorized;    no shares issued and outstanding	—			—
Common stock, $0.01 par value, 150,000,000 shares authorized;    67,276,761 and 67,187,224 shares issued at September 30, 2013    and December 31, 2012, respectively	673			672
Common stock, held in treasury, at cost; 506,525 and 284,493 shares    at September 30, 2013 and December 31, 2012, respectively	(32,711		)	(13,302		)
Additional paid-in capital	509,295			496,254
Retained earnings	1,798,721			1,399,472
Accumulated other comprehensive loss	(10,921		)	(10,840		)
Total stockholders' equity	2,265,057			1,872,256
Total liabilities and stockholders' equity	$	3,923,449		$	3,412,196

The accompanying notes are an integral part of these consolidated financial statements.

1

WESTLAKE CHEMICAL CORPORATION

CONSOLIDATED STATEMENTS OF OPERATIONS

(Unaudited)

	Three Months Ended September 30,						Nine Months Ended September 30,
	2013			2012			2013			2012
	(in thousands of dollars, except per share data and share amounts)
Net sales	$	1,004,165		$	821,175		$	2,807,859		$	2,770,000
Cost of sales	699,694			648,996			2,002,092			2,223,288
Gross profit	304,471			172,179			805,767			546,712
Selling, general and administrative expenses	37,869			29,662			109,883			87,592
Income from operations	266,602			142,517			695,884			459,120
Other income (expense)
Interest expense	(3,297		)	(11,934		)	(14,921		)	(35,682		)
Debt retirement costs	—			(7,082		)	—			(7,082		)
Gain from sales of equity securities	—			477			—			16,429
Other (expense) income, net	(287		)	1,222			3,137			3,676
Income before income taxes	263,018			125,200			684,100			436,461
Provision for income taxes	92,728			38,236			244,647			146,183
Net income	$	170,290		$	86,964		$	439,453		$	290,278
Earnings per share:
Basic	$	2.55		$	1.30		$	6.57		$	4.36
Diluted	$	2.54		$	1.30		$	6.54		$	4.33
Weighted average shares outstanding:
Basic	66,628,747			66,311,958			66,628,027			66,240,225
Diluted	66,905,554			66,656,760			66,903,379			66,621,520
Dividends per common share	$	0.2250		$	0.1875		$	0.6000		$	0.3350

The accompanying notes are an integral part of these consolidated financial statements.

2

WESTLAKE CHEMICAL CORPORATION

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME

(Unaudited)

	Three Months Ended September 30,						Nine Months Ended September 30,
	2013			2012			2013			2012
	(in thousands of dollars)
Net income	$	170,290		$	86,964		$	439,453		$	290,278
Other comprehensive (loss) income
Pension and other post-retirement benefits liability
Pension and other post-retirement reserves    adjustment (excluding amortization)	(489		)	72			(978		)	142
Amortization of benefits liability	695			584			2,004			1,747
Income tax provision on pension and other    post-retirement benefits liability	(78		)	(252		)	(394		)	(725		)
Foreign currency translation adjustments	546			865			(844		)	928
Reclassification of net cash flow hedge losses    to net income, net of income tax benefit	—			521			—			—
Available-for-sale investments
Unrealized holding gains on investments	205			339			205			14,582
Income tax provision on unrealized    holding gains	(74		)	(121		)	(74		)	(5,229		)
Reclassification of net realized gain to    net income	—			(306		)	—			(10,538		)
Other comprehensive income (loss)	805			1,702			(81		)	907
Comprehensive income	$	171,095		$	88,666		$	439,372		$	291,185

The accompanying notes are an integral part of these consolidated financial statements.

3

WESTLAKE CHEMICAL CORPORATION

CONSOLIDATED STATEMENTS OF CASH FLOWS

(Unaudited)

	Nine Months Ended September 30,
	2013			2012
	(in thousands of dollars)
Cash flows from operating activities
Net income	$	439,453		$	290,278
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	116,294			109,601
Provision for (recovery of) doubtful accounts	3,600			(536		)
Amortization of debt issuance costs	1,093			1,149
Stock-based compensation expense	4,804			4,640
Loss from disposition of fixed assets	4,679			1,945
Gain from sales of equity securities	—			(16,429		)
Write-off of debt issuance costs	—			1,277
Deferred income taxes	83,443			4,385
Windfall tax benefits from share-based payment arrangements	(5,056		)	(7,792		)
Equity in loss of joint ventures	1,586			2,567
Changes in operating assets and liabilities
Accounts receivable	(18,874		)	13,732
Inventories	(26,325		)	119,240
Prepaid expenses and other current assets	(5,038		)	(1,977		)
Accounts payable	19,518			(35,651		)
Accrued liabilities	(15,755		)	20,077
Other, net	(55,922		)	(13,675		)
Net cash provided by operating activities	547,500			492,831
Cash flows from investing activities
Acquisition of business	(178,309		)	—
Additions to equity investments	(23,338		)	—
Additions to property, plant and equipment	(498,290		)	(235,463		)
Construction of assets pending sale-leaseback	(136		)	(5,484		)
Proceeds from disposition of assets	78			435
Proceeds from repayment of loan to affiliate	167			763
Proceeds from sales and maturities of securities	239,764			47,655
Purchase of securities	(232,286		)	(2,961		)
Settlements of derivative instruments	(2,297		)	471
Net cash used for investing activities	(694,647		)	(194,584		)
Cash flows from financing activities
Capitalized debt issuance costs	—			(2,221		)
Dividends paid	(40,204		)	(22,345		)
Proceeds from debt issuance	—			248,818
Proceeds from exercise of stock options	3,182			6,627
Repayment of debt	—			(250,000		)
Repurchase of common stock for treasury	(19,409		)	(10,784		)
Utilization of restricted cash	—			96,433
Windfall tax benefits from share-based payment arrangements	5,056			7,792
Net cash (used for) provided by financing activities	(51,375		)	74,320
Net (decrease) increase in cash and cash equivalents	(198,522		)	372,567
Cash and cash equivalents at beginning of period	790,078			825,901
Cash and cash equivalents at end of period	$	591,556		$	1,198,468

The accompanying notes are an integral part of these consolidated financial statements.

4

WESTLAKE CHEMICAL CORPORATION

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

(Unaudited)

(in thousands of dollars, except share amounts and per share data)

1. Basis of Financial Statements

The accompanying unaudited consolidated interim financial statements were prepared in accordance with the rules and regulations of the Securities and Exchange Commission (the "SEC") for interim periods. Accordingly, certain information and footnotes required for complete financial statements under generally accepted accounting principles in the United States ("U.S. GAAP") have not been included. These interim consolidated financial statements should be read in conjunction with the December 31, 2012 financial statements and notes thereto of Westlake Chemical Corporation (the "Company") included in the annual report on Form 10-K for the fiscal year ended December 31, 2012 (the "2012 Form 10-K"), filed with the SEC on February 22, 2013. These financial statements have been prepared in conformity with the accounting principles and practices as disclosed in the notes to the consolidated financial statements of the Company for the fiscal year ended December 31, 2012.

In the opinion of the Company's management, the accompanying unaudited consolidated interim financial statements reflect all adjustments (consisting only of normal recurring adjustments) that are necessary for a fair statement of the Company's financial position as of September 30, 2013, its results of operations for the three and nine months ended September 30, 2013 and 2012 and the changes in its cash position for the nine months ended September 30, 2013 and 2012.

Results of operations and changes in cash position for the interim periods presented are not necessarily indicative of the results that will be realized for the fiscal year ending December 31, 2013 or any other interim period. The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities. Actual results could differ from those estimates.

Revisions

The consolidated statement of cash flows for the nine months ended September 30, 2012 has been revised to correct the presentation of windfall tax benefits from share-based compensation of $7,792 in financing activities, instead of operating activities. The Company has determined that this revision was immaterial to the Company's previously issued financial statements.

Recent Accounting Pronouncements

Disclosures about Offsetting Assets and Liabilities

In December 2011, the Financial Accounting Standards Board ("FASB") issued an accounting standards update on disclosures for offsetting assets and liabilities. The new accounting guidance requires companies to disclose both gross and net information about (1) instruments and transactions eligible for offset in the statement of financial position, and (2) instruments and transactions subject to an agreement similar to a master netting arrangement. The FASB issued another accounting standards update clarifying the scope of the assets and liabilities offset disclosure requirements in January 2013. The effective date of the disclosure requirements remains unchanged. The Company adopted the new guidance as of January 1, 2013, and the adoption did not have an impact on the Company's consolidated financial position, results of operations or cash flows.

Testing Indefinite-Lived Intangible Assets for Impairment

In July 2012, the FASB issued an accounting standards update to simplify how entities test indefinite-lived intangible assets for impairment and to improve consistency in impairment testing guidance among long-lived asset categories. The new accounting guidance provides an entity with an option to first assess qualitative factors to determine whether it is more likely than not that an indefinite-lived intangible asset is impaired as a basis for determining whether it is necessary to perform the quantitative impairment test under current accounting guidance. If an entity concludes that it is not more likely than not that the indefinite-lived intangible asset is impaired, then the entity is not required to take further action. However, if an entity concludes otherwise, then it is required to determine the fair value of the indefinite-lived intangible asset and perform the quantitative impairment test by comparing the fair value with the carrying amount in accordance with current accounting guidance. Also under this new accounting guidance, an entity has the option to bypass the qualitative assessment for any indefinite-lived intangible asset in any period and proceed directly to performing the quantitative impairment test, but may resume performing the qualitative assessment in any subsequent period. The Company adopted the new indefinite-lived intangible assets test guidance as of January 1, 2013, and the adoption did not have a material impact on the Company's consolidated financial position, results of operations or cash flows.

5

WESTLAKE CHEMICAL CORPORATION

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS - Continued

(Unaudited)

(in thousands of dollars, except share amounts and per share data)

Reclassifications Out of Accumulated Other Comprehensive Income

In February 2013, the FASB issued an accounting standards update on reporting items reclassified out of accumulated other comprehensive income. The new accounting guidance requires companies to present either parenthetically on the face of the financial statements or in the notes, significant amounts reclassified from each component of accumulated other comprehensive income and the income statement line items affected by the reclassification, with certain exceptions. The Company adopted the new guidance as of January 1, 2013, and the adoption did not have an impact on the Company's consolidated financial position, results of operations or cash flows.

2. Current Marketable Securities

The Company’s investments in current marketable securities were classified as follows:

	September 30, 2013		December 31, 2012
Available-for-sale securities	$	120,602	$	—
Held-to-maturity securities	4,995		124,873
Marketable securities	$	125,597	$	124,873

Available-for-Sale Securities

The cost, gross unrealized gains, gross unrealized losses and fair value of the Company’s available-for-sale securities were as follows:

	September 30, 2013
	Cost		Gross Unrealized Gains		Gross Unrealized Losses (1)			Fair Value
Debt securities
Corporate bonds	$	11,888	$	191	$	(21	)	$	12,058
U.S. government debt (2)	26,400		23		(6		)	26,417
Asset-backed securities	82,109		27		(9		)	82,127
Total available-for-sale securities	$	120,397	$	241	$	(36	)	$	120,602

_____________

(1) All unrealized loss positions were held at a loss for less than 12 months.

(2) U.S. Treasury obligations, U.S. government agency obligations and U.S government agency mortgage-backed securities.

As of September 30, 2013, net unrealized gains on the Company's available-for-sale securities of $131, net of income tax expense of $74, were recorded in accumulated other comprehensive income. See Note 10 for the fair value hierarchy of the Company’s available-for-sale securities.

As of September 30, 2013, the corporate bond securities held by the Company had maturities between one to five years, U.S. government debt securities, excluding U.S. government agency mortgage-backed securities, had maturities of less than one year, U.S. government agency mortgage-backed securities had maturities between four to 26 years and asset-backed securities had maturities between two to five years.

Held-to-Maturity Securities

The Company owned held-to-maturity securities of $4,995 and $124,873 at September 30, 2013 and December 31, 2012, respectively, consisting of short-term corporate debt securities with maturities exceeding three months at the date of acquisition. These debt securities are carried at amortized cost, which approximates their fair value.

6

WESTLAKE CHEMICAL CORPORATION

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS - Continued

(Unaudited)

(in thousands of dollars, except share amounts and per share data)

3. Accounts Receivable

Accounts receivable consist of the following:

	September 30, 2013			December 31, 2012
Trade customers	$	404,678		$	388,949
Affiliates	333			258
Allowance for doubtful accounts	(9,832		)	(11,172		)
	395,179			378,035
Federal and state taxes	20,421			4,011
Other	17,425			18,113
Accounts receivable, net	$	433,025		$	400,159

4. Inventories

Inventories consist of the following:

	September 30, 2013		December 31, 2012
Finished products	$	198,762	$	200,940
Feedstock, additives and chemicals	194,558		143,912
Materials and supplies	58,251		54,446
Inventories	$	451,571	$	399,298

5. Property, Plant and Equipment

As of September 30, 2013, the Company had property, plant and equipment, net totaling $1,952,918. The Company assesses these assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable, including when negative conditions such as significant current or projected operating losses exist. Other factors considered by the Company when determining if an impairment assessment is necessary include, but are not limited to, significant changes or projected changes in supply and demand fundamentals (which would have a negative impact on operating rates or margins), new technological developments, new competitors with significant raw material or other cost advantages, adverse changes associated with the U.S. and world economies and uncertainties associated with governmental actions. Long-lived assets assessed for impairment are grouped at the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets and liabilities.

Depreciation expense on property, plant and equipment of $32,460 and $30,055 is included in cost of sales in the consolidated statements of operations for the three months ended September 30, 2013 and 2012, respectively. Depreciation expense on property, plant and equipment of $95,995 and $90,615 is included in cost of sales in the consolidated statements of operations for the nine months ended September 30, 2013 and 2012, respectively.

6. Other Assets

Amortization expense on intangible and other assets of $8,634 and $8,717 is included in the consolidated statements of operations for the three months ended September 30, 2013 and 2012, respectively. Amortization expense on intangible and other assets of $21,392 and $20,135 is included in the consolidated statements of operations for the nine months ended September 30, 2013 and 2012, respectively.

7

WESTLAKE CHEMICAL CORPORATION

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS - Continued

(Unaudited)

(in thousands of dollars, except share amounts and per share data)

7. Long-Term Debt

Long-term debt consists of the following:

	September 30, 2013		December 31, 2012
3.60% senior notes due 2022	$	248,960	$	248,872
6 ½% senior notes due 2029	100,000		100,000
6 ¾% senior notes due 2032	250,000		250,000
6 ½% senior notes due 2035 (the "6 ½% GO Zone Senior Notes Due 2035")	89,000		89,000
6 ½% senior notes due 2035 (the "6 ½% IKE Zone Senior Notes Due 2035")	65,000		65,000
Loan related to tax-exempt waste disposal revenue bonds due 2027	10,889		10,889
Long-term debt, net	$	763,849	$	763,761

Revolving Credit Facility

The Company has a $400,000 senior secured revolving credit facility. The facility includes a provision permitting the Company to increase the size of the facility, up to four times, in increments of at least $25,000 each (up to a maximum of $150,000) under certain circumstances if lenders agree to commit to such an increase. At September 30, 2013, the Company had no borrowings outstanding under the revolving credit facility. Any borrowings under the facility will bear interest at either LIBOR plus a spread ranging from 1.75% to 2.25% or a base rate plus a spread ranging from 0.25% to 0.75%. The revolving credit facility also requires an unused commitment fee of 0.375% per annum. All interest rates under the facility are subject to monthly grid pricing adjustments based on prior month average daily loan availability. The revolving credit facility matures on September 16, 2016. As of September 30, 2013, the Company had outstanding letters of credit totaling $16,921 and borrowing availability of $383,079 under the revolving credit facility.

8. Stock-Based Compensation

Under the Westlake Chemical Corporation 2013 Omnibus Incentive Plan (as amended and restated, the "2013 Plan"), all employees and nonemployee directors of the Company, as well as certain individuals who have agreed to become the Company's employees, are eligible for awards. Shares of common stock may be issued as authorized in the 2013 Plan. At the discretion of the administrator of the 2013 Plan, employees and nonemployee directors may be granted awards in the form of stock options, stock appreciation rights, stock awards, restricted stock units or cash awards (any of which may be a performance award). Total stock-based compensation expense related to the 2013 Plan was $1,680 and $1,515 for the three months ended September 30, 2013 and 2012, respectively, and $4,804 and $4,640 for the nine months ended September 30, 2013 and 2012, respectively.

9. Derivative Instruments

Commodity Risk Management

The Company uses derivative instruments to reduce price volatility risk on raw materials and products as a substantial portion of its raw materials and products are commodities whose prices fluctuate as market supply and demand fundamentals change. Business strategies to protect against such instability include ethylene product feedstock flexibility and moving downstream into the olefins and vinyls products where pricing is more stable. The Company does not use derivative instruments to engage in speculative activities.

For derivative instruments that are designated and qualify as fair value hedges, the gains or losses on the derivative instruments, as well as the offsetting losses or gains on the hedged items attributable to the hedged risk, were included in cost of sales in the consolidated statements of operations for the three and nine months ended September 30, 2013 and 2012. As of September 30, 2013, the Company had 10,710,000 gallons of feedstock forward contracts designated as fair value hedges.

Gains and losses from changes in the fair value of derivative instruments that are not designated as hedging instruments were included in cost of sales in the consolidated statements of operations for the three and nine months ended September 30, 2013 and 2012.

The exposure on commodity derivatives used for price risk management includes the risk that the counterparty will not pay if the market declines below the established fixed price. In such case, the Company would lose the benefit of the derivative

8

WESTLAKE CHEMICAL CORPORATION

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS - Continued

(Unaudited)

(in thousands of dollars, except share amounts and per share data)

differential on the volume of the commodities covered. In any event, the Company would continue to receive the market price on the actual volume hedged. The Company also bears the risk that it could lose the benefit of market improvements over the fixed derivative price for the term and volume of the derivative instruments (as such improvements would accrue to the benefit of the counterparty).

Disclosures related to the Company's derivative assets and derivative liabilities subject to enforceable master netting arrangements have not been presented as they are not material to the Company's consolidated balance sheets at September 30, 2013 and December 31, 2012.

The fair values of derivative instruments in the Company's consolidated balance sheets were as follows:

	Derivative Assets
	Balance Sheet Location	Fair Value as of
		September 30, 2013		December 31, 2012
Designated as hedging instruments
Commodity forward contracts	Accounts receivable, net	$	3,208	$	13,032
Not designated as hedging instruments
Commodity forward contracts	Accounts receivable, net	2,541		1,395
Total derivative assets		$	5,749	$	14,427

	Derivative Liabilities
	Balance Sheet Location	Fair Value as of
		September 30, 2013		December 31, 2012
Designated as hedging instruments
Commodity forward contracts	Accrued liabilities	$	—	$	399
Not designated as hedging instruments
Commodity forward contracts	Accrued liabilities	2,090		13,295
Total derivative liabilities		$	2,090	$	13,694

The following tables reflect the impact of derivative instruments designated as fair value hedges and the related hedged item on the Company's consolidated statements of operations. For the three and nine months ended September 30, 2013 and 2012, there was no material ineffectiveness with regard to the Company's qualifying fair value hedges.

Derivatives in Fair Value    Hedging Relationships	Location of Gain (Loss) Recognized in  Income on Derivative	Three Months Ended September 30,						Nine Months Ended September 30,
		2013			2012			2013			2012
Commodity forward contracts	Cost of sales	$	(232	)	$	(515	)	$	(342	)	$	12,345
Hedged Items in Fair Value    Hedging Relationships	Location of Gain (Loss) Recognized in  Income on Hedged Items	Three Months Ended September 30,						Nine Months Ended September 30,
		2013			2012			2013			2012
Firm commitment designated    as the hedged item	Cost of sales	$	236		$	515		$	15		$	(13,546	)

The impact of derivative instruments that have not been designated as hedges on the Company's consolidated statements of operations were as follows:

Derivatives Not Designated as    Hedging Instruments	Location of Gain (Loss) Recognized in  Income on Derivative	Three Months Ended September 30,				Nine Months Ended September 30,
		2013		2012		2013		2012
Commodity forward contracts	Cost of sales	$	4,854	$	249	$	9,897	$	(783	)

See Note 10 for the fair value of the Company's derivative instruments.

9

WESTLAKE CHEMICAL CORPORATION

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS - Continued

(Unaudited)

(in thousands of dollars, except share amounts and per share data)

10. Fair Value Measurements

The Company reports certain assets and liabilities at fair value, which is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). Under the accounting guidance for fair value measurements, inputs used to measure fair value are classified in one of three levels:

Level 1: Quoted market prices in active markets for identical assets or liabilities.

Level 2: Observable market-based inputs or unobservable inputs that are corroborated by market data.

Level 3: Unobservable inputs that are not corroborated by market data.

The following tables summarize, by level within the fair value hierarchy, the Company's assets and liabilities that were accounted for at fair value on a recurring basis:

	September 30, 2013
	Level 1			Level 2			Total
Derivative instruments
Risk management assets - Commodity forward contracts	$	1,808		$	3,941		$	5,749
Risk management liabilities - Commodity forward contracts	(74		)	(2,016		)	(2,090		)
Firm commitments
Hedged portion of firm commitment	—			(3,208		)	(3,208		)
Marketable securities
Available-for-sale securities	14,998			105,604			120,602
	December 31, 2012
	Level 1			Level 2			Total
Derivative instruments
Risk management assets - Commodity forward contracts	$	1,395		$	13,032		$	14,427
Risk management liabilities - Commodity forward contracts	—			(13,694		)	(13,694		)
Firm commitments
Hedged portion of firm commitment	—			399			399
Hedged portion of firm commitment	—			(13,032		)	(13,032		)

The Level 2 measurements for the Company's commodity contracts are derived using forward curves supplied by industry-recognized and unrelated third-party services. The Level 2 measurements for the Company's available-for-sale securities are derived using market-based pricing provided by unrelated third-party services.

There were no transfers in and out of Levels 1 and 2 of the fair value hierarchy for the nine months ended September 30, 2013 and 2012.

In addition to the financial assets and liabilities above, the Company has other financial assets and liabilities subject to fair value measures. These financial assets and liabilities include cash and cash equivalents, accounts receivable, net, accounts payable and long-term debt, all of which are recorded at carrying value. The amounts reported in the consolidated balance sheets for cash and cash equivalents, accounts receivable, net and accounts payable approximate their fair value due to the short maturities of these instruments. The carrying and fair values of the Company's long-term debt are summarized in the table below. The Company's long-term debt instruments are publicly-traded. A market approach, based upon quotes from financial reporting services, is used to measure the fair value of the Company's long-term debt. Because the Company's long-term debt instruments may not be actively traded, the inputs used to measure the fair value of the Company's long-term debt are classified as Level 2 inputs within the fair value hierarchy.

10

WESTLAKE CHEMICAL CORPORATION

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS - Continued

(Unaudited)

(in thousands of dollars, except share amounts and per share data)

	September 30, 2013				December 31, 2012
	Carrying Value		Fair Value		Carrying Value		Fair Value
3.60% senior notes due 2022	$	248,960	$	238,228	$	248,872	$	251,125
6 ½% senior notes due 2029	100,000		107,800		100,000		119,738
6 ¾% senior notes due 2032	250,000		267,465		250,000		283,168
6 ½% GO Zone Senior Notes Due 2035	89,000		94,209		89,000		102,095
6 ½% IKE Zone Senior Notes Due 2035	65,000		68,804		65,000		74,564
Loan related to tax-exempt waste disposal revenue    bonds due 2027	10,889		10,889		10,889		10,889

11. Income Taxes

The effective income tax rate was 35.8% for the nine months ended September 30, 2013. The effective income tax rate for the 2013 period was above the U.S. federal statutory rate of 35.0% primarily due to state income taxes, partially offset by the domestic manufacturing deduction. The effective income tax rate was 33.5% for the nine months ended September 30, 2012. The effective income tax rate for the 2012 period was below the U.S. federal statutory rate of 35.0% primarily due to state tax credits and the domestic manufacturing deduction, partially offset by state income taxes.

There was no material change to the total gross unrecognized tax benefits for the nine months ended September 30, 2013. Management anticipates reductions to the total amount of unrecognized tax benefits of an additional $621 within the next twelve months due to expiring statutes of limitations.

The Company recognizes penalties and interest accrued related to unrecognized tax benefits in income tax expense. As of September 30, 2013, the Company had no material accrued interest and penalties related to uncertain tax positions.

The Company files income tax returns in the U.S. federal jurisdiction, various states and foreign jurisdictions. The Company is no longer subject to examinations by tax authorities before the year 2007.

12. Earnings per Share

The Company has unvested shares of restricted stock and restricted stock units outstanding that are considered participating securities and, therefore, computes basic and diluted earnings per share under the two-class method. Basic earnings per share for the periods are based upon the weighted average number of shares of common stock outstanding during the periods. Diluted earnings per share include the effect of certain stock options.

	Three Months Ended September 30,						Nine Months Ended September 30,
	2013			2012			2013			2012
Net income	$	170,290		$	86,964		$	439,453		$	290,278
Less:
Net income attributable to participating securities	(587		)	(452		)	(1,691		)	(1,682		)
Net income attributable to common shareholders	$	169,703		$	86,512		$	437,762		$	288,596

11

WESTLAKE CHEMICAL CORPORATION

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS - Continued

(Unaudited)

(in thousands of dollars, except share amounts and per share data)

The following table reconciles the denominator for the basic and diluted earnings per share computations shown in the consolidated statements of operations:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2013		2012		2013		2012
Weighted average common shares—basic	66,628,747		66,311,958		66,628,027		66,240,225
Plus incremental shares from:
Assumed exercise of options	276,807		344,802		275,352		381,295
Weighted average common shares—diluted	66,905,554		66,656,760		66,903,379		66,621,520
Earnings per share:
Basic	$	2.55	$	1.30	$	6.57	$	4.36
Diluted	$	2.54	$	1.30	$	6.54	$	4.33

Excluded from the computation of diluted earnings per share are options to purchase 68,662 and 168,362 shares of common stock for the three months ended September 30, 2013 and 2012, respectively, and 57,759 and 293,062 shares of common stock for the nine months ended September 30, 2013 and 2012, respectively. These options were outstanding during the periods reported but were excluded because the effect of including them would have been antidilutive.

13. Pension and Post-Retirement Benefit Costs

Components of net periodic benefit cost are as follows:

	Three Months Ended September 30,										Nine Months Ended September 30,
	Pension						Post-retirement Healthcare				Pension						Post-retirement Healthcare
	2013			2012			2013		2012		2013			2012			2013		2012
Service cost	$	275		$	250		$	2	$	2	$	815		$	754		$	7	$	7
Interest cost	515			645			147		185		1,531			1,936			442		555
Expected return on plan assets	(713		)	(623		)	—		—		(2,140		)	(1,867		)	—		—
Amortization of prior    service cost	74			74			21		21		223			223			63		63
Amortization of net loss	510			445			90		44		1,449			1,329			269		132
Net periodic benefit cost	$	661		$	791		$	260	$	252	$	1,878		$	2,375		$	781	$	757

The Company contributed $776 and $2,283 to the Salaried pension plan in the first nine months of 2013 and 2012, respectively, and contributed $640 and $1,542 to the Wage pension plan in the first nine months of 2013 and 2012, respectively. The Company expects to make additional contributions of $388 to the Salaried pension plan and $290 to the Wage pension plan during the fiscal year ending December 31, 2013.

12

WESTLAKE CHEMICAL CORPORATION

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS - Continued

(Unaudited)

(in thousands of dollars, except share amounts and per share data)

14. Accumulated Other Comprehensive Loss

Changes in accumulated other comprehensive income (loss) by component for the nine months ended September 30, 2013 were as follows:

	Benefits Liability, Net of Tax			Cumulative Foreign Currency Exchange			Net Unrealized Holding Gains on Investments, Net of Tax		Total
Balances at December 31, 2012	$	(16,351	)	$	5,511		$	—	$	(10,840	)
Other comprehensive (loss) income before    reclassifications	(601		)	(844		)	131		(1,314		)
Amounts reclassified from accumulated other    comprehensive loss	1,233			—			—		1,233
Net other comprehensive income (loss) for the period	632			(844		)	131		(81		)
Balances at September 30, 2013	$	(15,719	)	$	4,667		$	131	$	(10,921	)

The following table provides the details of the amounts reclassified from accumulated other comprehensive income (loss) into net income in the consolidated statements of operations for the three and nine months ended September 30, 2013:

Details about Accumulated Other Comprehensive    Income (Loss) Components	Location of Reclassification (Income (Expense)) in Consolidated Statements of Operations	Three Months Ended September 30, 2013			Nine Months Ended September 30, 2013
Amortization of pension and other post-retirement items
Prior service costs	(1)	$	(95	)	$	(286	)
Net loss	(1)	(600		)	(1,718		)
		(695		)	(2,004		)
	Provision for income taxes	267			771
Total reclassifications for the period		$	(428	)	$	(1,233	)

_____________

(1) These accumulated other comprehensive loss components are included in the computation of net periodic benefit cost. For additional information, please read Note 8 (Employee Benefits) to the financial statements included in the 2012 Form 10-K.

15. Acquisitions

On May 1, 2013, the Company acquired assets comprising CertainTeed Corporation's Pipe and Foundation Group ("PFG") business and accounted for the asset acquisition as a business combination. The PFG acquisition includes the PVC pipe, fittings, profiles and foundation business and associated facilities in Lodi, California and McPherson, Kansas with production capacity of approximately 150 million pounds per year. The Company also acquired technologies and intellectual property for the production of a number of specialized products, including Certa-Lok® restrained joint pipe and Yelomine™ branded products for a variety of end-market applications. The Company's management believes that this acquisition will enhance the Company's building products portfolio by adding new specialty product lines and supporting technology.

The closing date purchase price of $178,309 was paid with available cash on hand. This amount is subject to a post-closing working capital adjustment. The acquisition is being accounted for under the acquisition method of accounting. The assets acquired and liabilities assumed and the results of operations of this acquired business are included in the Vinyls segment. The revenue and earnings of the PFG business included in the consolidated statement of operations since the acquisition date have not been presented separately as they are not material to the Company's consolidated statements of operations for the three and nine months ended September 30, 2013. The pro forma impact of this business combination has not been presented as it is not material to the Company's consolidated statements of operations for the three and nine months ended September 30, 2013 and 2012.

For the nine months ended September 30, 2013, the Company recognized $1,124 of acquisition-related costs. These costs are included in selling, general and administrative expenses in the consolidated statement of operations for the nine months ended September 30, 2013.

13

WESTLAKE CHEMICAL CORPORATION

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS - Continued

(Unaudited)

(in thousands of dollars, except share amounts and per share data)

The following table summarizes the consideration transferred and the estimated fair value of identified assets acquired and liabilities assumed at the date of acquisition. The final determination of fair value for certain assets and liabilities will be completed as soon as the information necessary to complete the analysis is obtained. These amounts will be finalized as soon as possible, but no later than one year from the acquisition date.

Fair value of consideration transferred:
Cash	$	178,309
Preliminary allocation of consideration transferred to net assets acquired:
Accounts receivable (1)	$	17,695
Inventories	25,948
Property, plant and equipment	31,261
Intangible assets:
Customer relationships (weighted average life of 15 years)	57,600
Trademarks	5,200
Developed technology (weighted average life of 15 years)	18,900
Other intangibles (weighted average life of two years)	300
Current liabilities	(10,595		)
Other liabilities	(26		)
Total identifiable net assets	146,283
Goodwill (2)	32,026
Consideration transferred	$	178,309

_____________

(1) The fair value of accounts receivable acquired is $17,695, with the gross contractual amount being $17,772. The Company expects $77 to be uncollectible.

(2) The goodwill recognized is primarily attributable to synergies from the Company's vinyls integration strategy expected to arise from the Company's PFG acquisition, as well as intangible assets that do not qualify for separate recognition. The goodwill is expected to be deductible for income tax purposes. The Company has not yet completed the process of assigning the goodwill to its reporting units.

Supplemental Noncash Investing Cash Flow Information

In conjunction with the acquisition, liabilities assumed consist of the following:

Fair value of assets acquired	$	188,930
Cash paid	(178,309		)
Liabilities assumed	$	10,621

16. Commitments and Contingencies

The Company is subject to environmental laws and regulations that can impose civil and criminal sanctions and that may require it to mitigate the effects of contamination caused by the release or disposal of hazardous substances into the environment. Under one law, an owner or operator of property may be held strictly liable for remediating contamination without regard to whether that person caused the contamination, and without regard to whether the practices that resulted in the contamination were legal at the time they occurred. Because several of the Company's production sites have a history of industrial use, it is impossible to predict precisely what effect these legal requirements will have on the Company.

Contract Disputes with Goodrich and PolyOne. In connection with the 1990 and 1997 acquisitions of the Goodrich Corporation ("Goodrich") chemical manufacturing complex in Calvert City, Kentucky, Goodrich agreed to indemnify the Company for any liabilities related to preexisting contamination at the complex. For its part, the Company agreed to indemnify Goodrich for post-closing contamination caused by the Company's operations. The soil and groundwater at the complex, which does not include the Company's nearby PVC facility, had been extensively contaminated under Goodrich's operations. In 1993,

14

WESTLAKE CHEMICAL CORPORATION

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS - Continued

(Unaudited)

(in thousands of dollars, except share amounts and per share data)

Goodrich spun off the predecessor of PolyOne Corporation ("PolyOne"), and that predecessor assumed Goodrich's indemnification obligations relating to preexisting contamination.

In 2003, litigation arose among the Company, Goodrich and PolyOne with respect to the allocation of the cost of remediating contamination at the site. The parties settled this litigation in December 2007 and the case was dismissed. In the settlement the parties agreed that, among other things: (1) PolyOne would pay 100% of the costs (with specified exceptions), net of recoveries or credits from third parties, incurred with respect to environmental issues at the Calvert City site from August 1, 2007 forward; (2) either the Company or PolyOne might, from time to time in the future (but not more than once every five years), institute an arbitration proceeding to adjust that percentage; and (3) the Company and PolyOne would negotiate a new environmental remediation utilities and services agreement to cover the Company's provision to or on behalf of PolyOne of certain environmental remediation services at the site. The current environmental remediation activities at the Calvert City complex do not have a specified termination date but are expected to last for the foreseeable future. The costs incurred by the Company that have been invoiced to PolyOne to provide the environmental remediation services were $2,687 in 2012. By letter dated March 16, 2010, PolyOne notified the Company that it was initiating an arbitration proceeding under the settlement agreement. In this proceeding, PolyOne seeks to readjust the percentage allocation of costs and to recover approximately $1,400 from the Company in reimbursement of previously paid remediation costs. The arbitration is currently stayed.

Administrative Proceedings. There are several administrative proceedings in Kentucky involving the Company, Goodrich and PolyOne related to the same manufacturing complex in Calvert City. In 2003, the Kentucky Environmental and Public Protection Cabinet (the "Cabinet") re-issued Goodrich's Resource Conservation and Recovery Act ("RCRA") permit which requires Goodrich to remediate contamination at the Calvert City manufacturing complex. Both Goodrich and PolyOne challenged various terms of the permit in an attempt to shift Goodrich's clean-up obligations under the permit to the Company. The Company intervened in the proceedings. The Cabinet has suspended all corrective action under the RCRA permit in deference to a remedial investigation and feasibility study ("RIFS") being conducted pursuant to an Administrative Settlement Agreement ("AOC"), which became effective on December 9, 2009. See "Change in Regulatory Regime" below. The proceedings have been postponed. Periodic status conferences will be held to evaluate whether additional proceedings will be required.

Change in Regulatory Regime. In May 2009, the Cabinet sent a letter to the U.S. Environmental Protection Agency ("EPA") requesting the EPA's assistance in addressing contamination at the Calvert City site under the U.S. Comprehensive Environmental Response, Compensation, and Liability Act ("CERCLA"). In its response to the Cabinet also in May 2009, the EPA stated that it concurred with the Cabinet's request and would incorporate work previously conducted under the Cabinet's RCRA authority into the EPA's cleanup efforts under CERCLA. Since 1983, the EPA has been addressing contamination at an abandoned landfill adjacent to the Company's plant which had been operated by Goodrich and which was being remediated pursuant to CERCLA. During the past two years, the EPA has directed Goodrich and PolyOne to conduct additional investigation activities at the landfill and at the Company's plant. In June 2009, the EPA notified the Company that the Company may have potential liability under section 107(a) of CERCLA at its plant site. Liability under section 107(a) of CERCLA is strict and joint and several. The EPA also identified Goodrich and PolyOne, among others, as potentially responsible parties at the plant site. The Company negotiated, in conjunction with the other potentially responsible parties, the AOC and an order to conduct the RIFS. The parties submitted and received EPA approval for a RIFS work plan to implement the AOC. On July 12, 2013, the parties submitted separate draft RIFS reports to the EPA.

Monetary Relief. Except as noted above with respect to the settlement of the contract litigation among the Company, Goodrich and PolyOne, none of the court, the Cabinet nor the EPA has established any allocation of the costs of remediation among the various parties that are involved in the judicial and administrative proceedings discussed above. At this time, the Company is not able to estimate the loss or reasonable possible loss, if any, on the Company's financial statements that could result from the resolution of these proceedings. Any cash expenditures that the Company might incur in the future with respect to the remediation of contamination at the complex would likely be spread out over an extended period. As a result, the Company believes it is unlikely that any remediation costs allocable to it will be material in terms of expenditures made in any individual reporting period.

In addition to the matters described above, the Company is involved in various routine legal proceedings incidental to the conduct of its business. The Company does not believe that any of these routine legal proceedings will have a material adverse effect on its financial condition, results of operations or cash flows.

15

WESTLAKE CHEMICAL CORPORATION

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS - Continued

(Unaudited)

(in thousands of dollars, except share amounts and per share data)

17. Segment Information

The Company operates in two principal business segments: Olefins and Vinyls. These segments are strategic business units that offer a variety of different products. The Company manages each segment separately as each business requires different technology and marketing strategies.

	Three Months Ended September 30,						Nine Months Ended September 30,
	2013			2012			2013			2012
Net external sales
Olefins
Polyethylene	$	460,105		$	431,614		$	1,294,566		$	1,275,057
Styrene, feedstock and other	219,234			108,171			590,959			669,718
Total Olefins	679,339			539,785			1,885,525			1,944,775
Vinyls
PVC, caustic soda and other	212,041			191,310			612,391			569,316
Building products	112,785			90,080			309,943			255,909
Total Vinyls	324,826			281,390			922,334			825,225
	$	1,004,165		$	821,175		$	2,807,859		$	2,770,000
Intersegment sales
Olefins	$	85,454		$	76,771		$	230,607		$	247,671
Vinyls	403			391			1,111			1,167
	$	85,857		$	77,162		$	231,718		$	248,838
Income (loss) from operations
Olefins	$	237,239		$	124,452		$	585,958		$	409,550
Vinyls	39,554			24,059			136,123			67,724
Corporate and other	(10,191		)	(5,994		)	(26,197		)	(18,154		)
	$	266,602		$	142,517		$	695,884		$	459,120
Depreciation and amortization
Olefins	$	26,515		$	27,070		$	76,415		$	74,903
Vinyls	14,089			11,232			39,507			34,330
Corporate and other	124			122			372			368
	$	40,728		$	38,424		$	116,294		$	109,601
Other income (expense), net
Olefins	$	728		$	806		$	5,889		$	2,764
Vinyls	(742		)	146			(1,687		)	115
Corporate and other	(273		)	270			(1,065		)	797
	$	(287	)	$	1,222		$	3,137		$	3,676
Provision for (benefit from) income taxes
Olefins	$	82,553		$	36,092		$	208,170		$	130,612
Vinyls	10,710			6,556			44,120			18,989
Corporate and other	(535		)	(4,412		)	(7,643		)	(3,418		)
	$	92,728		$	38,236		$	244,647		$	146,183

16

WESTLAKE CHEMICAL CORPORATION

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS - Continued

(Unaudited)

(in thousands of dollars, except share amounts and per share data)

	Three Months Ended September 30,				Nine Months Ended September 30,
	2013		2012		2013		2012
Capital expenditures
Olefins	$	27,577	$	46,867	$	105,656	$	92,168
Vinyls	172,565		47,001		391,864		139,836
Corporate and other	276		1,027		770		3,459
	$	200,418	$	94,895	$	498,290	$	235,463

A reconciliation of total segment income from operations to consolidated income before income taxes is as follows:

	Three Months Ended September 30,						Nine Months Ended September 30,
	2013			2012			2013			2012
Income from operations	$	266,602		$	142,517		$	695,884		$	459,120
Interest expense	(3,297		)	(11,934		)	(14,921		)	(35,682		)
Debt retirement costs	—			(7,082		)	—			(7,082		)
Gain from sales of equity securities	—			477			—			16,429
Other (expense) income, net	(287		)	1,222			3,137			3,676
Income before income taxes	$	263,018		$	125,200		$	684,100		$	436,461

	September 30, 2013		December 31, 2012
Total assets
Olefins	$	1,560,303	$	1,439,308
Vinyls	1,577,549		1,030,912
Corporate and other	785,597		941,976
	$	3,923,449	$	3,412,196

18. Goodwill

The changes in the carrying amount of goodwill for the nine months ended September 30, 2013 were as follows:

	Olefins Segment		Vinyls Segment		Total
Balance at December 31, 2012	$	29,990	$	—	$	29,990
Goodwill acquired during the period	—		32,026		32,026
Balance at September 30, 2013	$	29,990	$	32,026	$	62,016

19. Subsequent Events

Subsequent events were evaluated through the date on which the financial statements were issued.

17

WESTLAKE CHEMICAL CORPORATION

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS - Continued

(Unaudited)

(in thousands of dollars, except share amounts and per share data)

20. Guarantor Disclosures

The Company's payment obligations under the 3.60% senior notes due 2022 are fully and unconditionally guaranteed by each of its current and future domestic subsidiaries that guarantee other debt of the Company or of another guarantor of the 3.60% senior notes due 2022 in excess of $5,000 (the "Guarantor Subsidiaries"). Each Guarantor Subsidiary is 100% owned by Westlake Chemical Corporation. These guarantees are the joint and several obligations of the Guarantor Subsidiaries. The following unaudited condensed consolidating financial information presents the financial condition, results of operations and cash flows of Westlake Chemical Corporation, the Guarantor Subsidiaries and the remaining subsidiaries that do not guarantee the 3.60% senior notes due 2022 (the "Non-Guarantor Subsidiaries"), together with consolidating adjustments necessary to present the Company's results on a consolidated basis.

Condensed Consolidating Financial Information as of September 30, 2013

	Westlake Chemical Corporation		Guarantor Subsidiaries		Non- Guarantor Subsidiaries		Eliminations			Consolidated
Balance Sheet
Current assets
Cash and cash equivalents	$	560,261	$	4,494	$	26,801	$	—		$	591,556
Marketable securities	125,597		—		—		—			125,597
Accounts receivable, net	5,373		694,473		5,489		(272,310		)	433,025
Inventories	—		435,540		16,031		—			451,571
Prepaid expenses and other    current assets	468		15,931		2,410		—			18,809
Deferred income taxes	431		21,744		118		—			22,293
Total current assets	692,130		1,172,182		50,849		(272,310		)	1,642,851
Property, plant and equipment, net	—		1,945,405		7,513		—			1,952,918
Equity investments	2,635,954		98,823		31,634		(2,700,923		)	65,488
Other assets, net	16,969		251,703		506		(6,986		)	262,192
Total assets	$	3,345,053	$	3,468,113	$	90,502	$	(2,980,219	)	$	3,923,449
Current liabilities
Accounts payable	$	311,357	$	220,106	$	4,322	$	(277,718	)	$	258,067
Accrued liabilities	15,679		151,654		1,878		5,408			174,619
Total current liabilities	327,036		371,760		6,200		(272,310		)	432,686
Long-term debt	752,960		10,889		—		—			763,849
Deferred income taxes	—		416,404		748		(6,986		)	410,166
Other liabilities	—		51,640		51		—			51,691
Stockholders' equity	2,265,057		2,617,420		83,503		(2,700,923		)	2,265,057
Total liabilities and stockholders' equity	$	3,345,053	$	3,468,113	$	90,502	$	(2,980,219	)	$	3,923,449

18

WESTLAKE CHEMICAL CORPORATION

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS - Continued

(Unaudited)

(in thousands of dollars, except share amounts and per share data)

Condensed Consolidating Financial Information as of December 31, 2012

	Westlake Chemical Corporation		Guarantor Subsidiaries		Non-Guarantor Subsidiaries		Eliminations			Consolidated
Balance Sheet
Current assets
Cash and cash equivalents	$	753,881	$	6,973	$	29,224	$	—		$	790,078
Marketable securities	124,873		—		—		—			124,873
Accounts receivable, net	7,933		1,675,274		2,959		(1,286,007		)	400,159
Inventories	—		385,140		14,158		—			399,298
Prepaid expenses and other    current assets	389		11,386		2,925		—			14,700
Deferred income taxes	431		21,581		293		—			22,305
Total current assets	887,507		2,100,354		49,559		(1,286,007		)	1,751,413
Property, plant and equipment, net	—		1,502,902		7,146		—			1,510,048
Equity investments	3,018,926		65,448		32,923		(3,073,561		)	43,736
Other assets, net	17,033		94,678		1,252		(5,964		)	106,999
Total assets	$	3,923,466	$	3,763,382	$	90,880	$	(4,365,532	)	$	3,412,196
Current liabilities
Accounts payable	$	1,285,530	$	192,443	$	13,969	$	(1,274,892	)	$	217,050
Accrued liabilities	12,808		178,915		852		(11,115		)	181,460
Total current liabilities	1,298,338		371,358		14,821		(1,286,007		)	398,510
Long-term debt	752,872		10,889		—		—			763,761
Deferred income taxes	—		331,320		934		(5,964		)	326,290
Other liabilities	—		51,312		67		—			51,379
Stockholders' equity	1,872,256		2,998,503		75,058		(3,073,561		)	1,872,256
Total liabilities and stockholders' equity	$	3,923,466	$	3,763,382	$	90,880	$	(4,365,532	)	$	3,412,196

19

WESTLAKE CHEMICAL CORPORATION

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS - Continued

(Unaudited)

(in thousands of dollars, except share amounts and per share data)

Condensed Consolidating Financial Information for the Three Months Ended September 30, 2013

	Westlake Chemical Corporation			Guarantor Subsidiaries			Non- Guarantor Subsidiaries			Eliminations			Consolidated
Statement of Operations
Net sales	$	—		$	992,413		$	13,337		$	(1,585	)	$	1,004,165
Cost of sales	—			689,388			11,891			(1,585		)	699,694
Gross profit	—			303,025			1,446			—			304,471
Selling, general and administrative    expenses	514			35,714			1,641			—			37,869
(Loss) income from operations	(514		)	267,311			(195		)	—			266,602
Interest expense	(3,292		)	(5		)	—			—			(3,297		)
Other income (expense), net	3,585			(3,821		)	(51		)	—			(287		)
(Loss) income before income taxes	(221		)	263,485			(246		)	—			263,018
(Benefit from) provision for income taxes	(70		)	92,849			(51		)	—			92,728
Equity in net income of subsidiaries	170,441			—			—			(170,441		)	—
Net income (loss)	$	170,290		$	170,636		$	(195	)	$	(170,441	)	$	170,290
Comprehensive income	$	171,095		$	170,764		$	351		$	(171,115	)	$	171,095

Condensed Consolidating Financial Information for the Three Months Ended September 30, 2012

	Westlake Chemical Corporation			Guarantor Subsidiaries			Non- Guarantor Subsidiaries			Eliminations			Consolidated
Statement of Operations
Net sales	$	—		$	809,164		$	13,876		$	(1,865	)	$	821,175
Cost of sales	—			638,892			11,969			(1,865		)	648,996
Gross profit	—			170,272			1,907			—			172,179
Selling, general and administrative    expenses	498			27,601			1,563			—			29,662
(Loss) income from operations	(498		)	142,671			344			—			142,517
Interest expense	(11,919		)	(15		)	—			—			(11,934		)
Debt retirement costs	(7,082		)	—			—			—			(7,082		)
Gain from sales of equity securities	—			477			—			—			477
Other income (expense), net	4,556			(2,744		)	(590		)	—			1,222
(Loss) income before income taxes	(14,943		)	140,389			(246		)	—			125,200
(Benefit from) provision for income taxes	(4,498		)	42,596			138			—			38,236
Equity in net income of subsidiaries	97,409			—			—			(97,409		)	—
Net income (loss)	$	86,964		$	97,793		$	(384	)	$	(97,409	)	$	86,964
Comprehensive income	$	88,666		$	98,109		$	481		$	(98,590	)	$	88,666

20

WESTLAKE CHEMICAL CORPORATION

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS - Continued

(Unaudited)

(in thousands of dollars, except share amounts and per share data)

Condensed Consolidating Financial Information for the Nine Months Ended September 30, 2013

	Westlake Chemical Corporation			Guarantor Subsidiaries			Non- Guarantor Subsidiaries			Eliminations			Consolidated
Statement of Operations
Net sales	$	—		$	2,777,280		$	37,561		$	(6,982	)	$	2,807,859
Cost of sales	—			1,976,131			32,943			(6,982		)	2,002,092
Gross profit	—			801,149			4,618			—			805,767
Selling, general and administrative    expenses	1,576			103,478			4,829			—			109,883
(Loss) income from operations	(1,576		)	697,671			(211		)	—			695,884
Interest expense	(14,882		)	(39		)	—			—			(14,921		)
Other income (expense), net	7,490			(2,473		)	(1,880		)	—			3,137
(Loss) income before income taxes	(8,968		)	695,159			(2,091		)	—			684,100
(Benefit from) provision for income taxes	(3,202		)	248,301			(452		)	—			244,647
Equity in net income of subsidiaries	445,219			—			—			(445,219		)	—
Net income (loss)	$	439,453		$	446,858		$	(1,639	)	$	(445,219	)	$	439,453
Comprehensive income (loss)	$	439,372		$	447,490		$	(2,483	)	$	(445,007	)	$	439,372

Condensed Consolidating Financial Information for the Nine Months Ended September 30, 2012

	Westlake Chemical Corporation			Guarantor Subsidiaries			Non- Guarantor Subsidiaries			Eliminations			Consolidated
Statement of Operations
Net sales	$	—		$	2,738,180		$	37,154		$	(5,334	)	$	2,770,000
Cost of sales	—			2,197,300			31,322			(5,334		)	2,223,288
Gross profit	—			540,880			5,832			—			546,712
Selling, general and administrative    expenses	1,500			81,288			4,804			—			87,592
(Loss) income from operations	(1,500		)	459,592			1,028			—			459,120
Interest expense	(35,652		)	(30		)	—			—			(35,682		)
Debt retirement costs	(7,082		)	—			—			—			(7,082		)
Gain from sales of equity securities	1			16,428			—			—			16,429
Other income (expense), net	12,044			(5,724		)	(2,644		)	—			3,676
(Loss) income before income taxes	(32,189		)	470,266			(1,616		)	—			436,461
(Benefit from) provision for income taxes	(11,105		)	158,228			(940		)	—			146,183
Equity in net income of subsidiaries	311,362			—			—			(311,362		)	—
Net income (loss)	$	290,278		$	312,038		$	(676	)	$	(311,362	)	$	290,278
Comprehensive income	$	291,185		$	312,017		$	252		$	(312,269	)	$	291,185

21

WESTLAKE CHEMICAL CORPORATION

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS - Continued

(Unaudited)

(in thousands of dollars, except share amounts and per share data)

Condensed Consolidating Financial Information for the Nine Months Ended September 30, 2013

	Westlake Chemical Corporation			Guarantor Subsidiaries			Non- Guarantor Subsidiaries			Eliminations			Consolidated
Statement of Cash Flows
Cash flows from operating activities
Net income (loss)	$	439,453		$	446,858		$	(1,639	)	$	(445,219	)	$	439,453
Adjustments to reconcile net income    (loss) to net cash (used for) provided    by operating activities
Depreciation and amortization	1,094			114,432			1,861			—			117,387
Deferred income taxes	(1,102		)	84,532			13			—			83,443
Net changes in working capital    and other	(458,336		)	(87,330		)	7,664			445,219			(92,783		)
Net cash (used for) provided by    operating activities	(18,891		)	558,492			7,899			—			547,500
Cash flows from investing activities
Acquisition of business	—			(178,309		)	—			—			(178,309		)
Additions to equity investments	—			(23,338		)	—			—			(23,338		)
Additions to property, plant and    equipment	—			(496,027		)	(2,263		)	—			(498,290		)
Construction of assets pending    sale-leaseback	—			(136		)	—			—			(136		)
Proceeds from disposition of assets	—			6			72			—			78
Proceeds from repayment of loan    to affiliate	—			—			167			—			167
Proceeds from sales and maturities of    securities	239,764			—			—			—			239,764
Purchase of securities	(232,286		)	—			—			—			(232,286		)
Settlements of derivative instruments	—			(2,297		)	—			—			(2,297		)
Net cash provided by (used for)    investing activities	7,478			(700,101		)	(2,024		)	—			(694,647		)
Cash flows from financing activities
Intercompany financing	(130,832		)	139,130			(8,298		)	—			—
Dividends paid	(40,204		)	—			—			—			(40,204		)
Proceeds from exercise of stock options	3,182			—			—			—			3,182
Repurchase of common stock for treasury	(19,409		)	—			—			—			(19,409		)
Windfall tax benefits from share-based    payment arrangements	5,056			—			—			—			5,056
Net cash (used for) provided by    financing activities	(182,207		)	139,130			(8,298		)	—			(51,375		)
Net decrease in cash and cash equivalents	(193,620		)	(2,479		)	(2,423		)	—			(198,522		)
Cash and cash equivalents at beginning    of period	753,881			6,973			29,224			—			790,078
Cash and cash equivalents at end of period	$	560,261		$	4,494		$	26,801		$	—		$	591,556

22

WESTLAKE CHEMICAL CORPORATION

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS - Continued

(Unaudited)

(in thousands of dollars, except share amounts and per share data)

Condensed Consolidating Financial Information for the Nine Months Ended September 30, 2012

	Westlake Chemical Corporation			Guarantor Subsidiaries			Non- Guarantor Subsidiaries			Eliminations			Consolidated
Statement of Cash Flows
Cash flows from operating activities
Net income (loss)	$	290,278		$	312,038		$	(676	)	$	(311,362	)	$	290,278
Adjustments to reconcile net income    (loss) to net cash (used for) provided    by operating activities
Depreciation and amortization	1,149			107,191			2,410			—			110,750
Deferred income taxes	(176		)	3,932			629			—			4,385
Net changes in working capital    and other	(317,955		)	95,909			(1,898		)	311,362			87,418
Net cash (used for) provided by    operating activities	(26,704		)	519,070			465			—			492,831
Cash flows from investing activities
Additions to property, plant and    equipment	—			(234,713		)	(750		)	—			(235,463		)
Construction of assets pending    sale-leaseback	—			(5,484		)	—			—			(5,484		)
Proceeds from disposition of assets	—			414			21			—			435
Proceeds from repayment of loan    to affiliate	—			—			763			—			763
Proceeds from sales of equity securities	3			47,652			—			—			47,655
Purchase of securities	—			(2,961		)	—			—			(2,961		)
Settlements of derivative instruments	—			471			—			—			471
Net cash provided by (used for)    investing activities	3			(194,621		)	34			—			(194,584		)
Cash flows from financing activities
Intercompany financing	317,185			(321,273		)	4,088			—			—
Capitalized debt issuance costs	(2,221		)	—			—			—			(2,221		)
Dividends paid	(22,345		)	—			—			—			(22,345		)
Proceeds from borrowings	248,818			—			—			—			248,818
Proceeds from exercise of stock options	6,627			—			—			—			6,627
Repayment of borrowings	(250,000		)	—			—			—			(250,000		)
Repurchase of common stock for treasury	(10,784		)	—			—			—			(10,784		)
Utilization of restricted cash	96,433			—			—			—			96,433
Windfall tax benefits from share-based    payment arrangements	7,792			—			—			—			7,792
Net cash provided by (used for)    financing activities	391,505			(321,273		)	4,088			—			74,320
Net increase in cash and cash equivalents	364,804			3,176			4,587			—			372,567
Cash and cash equivalents at beginning    of period	803,320			2,517			20,064			—			825,901
Cash and cash equivalents at end of period	$	1,168,124		$	5,693		$	24,651		$	—		$	1,198,468

23

Item 2. Management's Discussion and Analysis of Financial Condition and Results of Operations

This discussion and analysis should be read in conjunction with information contained in the accompanying unaudited consolidated interim financial statements of Westlake Chemical Corporation and the notes thereto and the consolidated financial statements and notes thereto of Westlake Chemical Corporation included in Westlake Chemical Corporation's Annual Report on Form 10-K for the fiscal year ended December 31, 2012 (the "2012 Form 10-K"). The following discussion contains forward-looking statements. Please read "Forward-Looking Statements" for a discussion of limitations inherent in such statements.

We are a vertically integrated manufacturer and marketer of petrochemicals, polymers and fabricated building products. Our two principal business segments are Olefins and Vinyls. We use the majority of our internally-produced basic chemicals to produce higher value-added chemicals and building products.

Since 2009 and continuing through the third quarter of 2013, a cost advantage for natural gas liquids-based ethylene producers over naphtha-based ethylene producers has allowed a strong export market for ethylene derivatives and higher margins for North American chemical producers, including Westlake. Increased global demand for polyethylene in recent years in particular has resulted in improved operating margins and cash flow for our Olefins segment. However, some olefins industry consultants predict that a significant increase in worldwide ethylene and ethylene derivative capacity may occur within the next decade, with the largest increases in Asia and North America. As a result, our Olefins segment operating margins may be negatively impacted.

Continued weakness in the U.S. construction markets and budgetary constraints in municipal spending have contributed to lower domestic demand for our vinyls products. In addition, increases in feedstock costs, combined with the industry's inability to sufficiently raise domestic prices for polyvinyl chloride ("PVC") resin and building products in order to offset cost increases, affected our Vinyls segment's operating results in 2010 and 2011. However, since late 2010, the PVC industry has experienced an increase in PVC resin export demand, driven largely by more competitive feedstock and energy cost positions in North America. As a consequence, domestic PVC resin industry operating rates have improved since 2010, largely due to higher PVC resin export shipments. However, looking forward, our Vinyls segment operating rates and margins may continue to be negatively impacted by the slow recovery of U.S. construction markets.

The current U.S. economic environment, while slowly improving, continues to be somewhat challenging for our customers. However, we believe our customer base is generally healthy. As we continue to manage our business in this environment, including the slowdown in construction activity, we have taken steps designed to address the changes in demand and margins in our Vinyls segment and its resulting impact on our operations by matching production with sales demand and continuing to operate our plants in an efficient manner. We continue to monitor our cost management programs and discretionary capital spending. The impact of the weak global economic environment has been challenging to our business and, depending on the performance of the global economy in the remainder of 2013 and beyond, could have a negative effect on our financial condition, results of operations or cash flows.

Recent Developments

In August 2008, we announced plans for the construction of a new chlor-alkali plant at our vinyls manufacturing complex in Geismar, Louisiana. We commenced construction of the plant in 2011. Presently, we expect the new chlor-alkali plant to be operational by the end of 2013. The new chlor-alkali plant is designed to produce 350,000 electro chemical units ("ECUs"), or 700 million pounds of chlorine, per annum. The new plant is expected to improve the vertical integration of our vinyls business from chlorine downstream into vinyl chloride monomer ("VCM") and PVC and increase caustic soda sales.

24

Results of Operations

	Three Months Ended September 30,						Nine Months Ended September 30,
	2013			2012			2013			2012
	(dollars in thousands, except per share data)
Net external sales
Olefins
Polyethylene	$	460,105		$	431,614		$	1,294,566		$	1,275,057
Styrene, feedstock and other	219,234			108,171			590,959			669,718
Total Olefins	679,339			539,785			1,885,525			1,944,775
Vinyls
PVC, caustic soda and other	212,041			191,310			612,391			569,316
Building products	112,785			90,080			309,943			255,909
Total Vinyls	324,826			281,390			922,334			825,225
Total	$	1,004,165		$	821,175		$	2,807,859		$	2,770,000
Income (loss) from operations
Olefins	$	237,239		$	124,452		$	585,958		$	409,550
Vinyls	39,554			24,059			136,123			67,724
Corporate and other	(10,191		)	(5,994		)	(26,197		)	(18,154		)
Total income from operations	266,602			142,517			695,884			459,120
Interest expense	(3,297		)	(11,934		)	(14,921		)	(35,682		)
Debt retirement costs	—			(7,082		)	—			(7,082		)
Gain from sales of equity securities	—			477			—			16,429
Other (expense) income, net	(287		)	1,222			3,137			3,676
Provision for income taxes	92,728			38,236			244,647			146,183
Net income	$	170,290		$	86,964		$	439,453		$	290,278
Diluted earnings per share	$	2.54		$	1.30		$	6.54		$	4.33
	Three Months Ended September 30, 2013						Nine Months Ended September 30, 2013
	Average Sales Price			Volume			Average Sales Price			Volume
Product sales price and volume percentage    change from prior year period
Olefins	+11.5		%	+14.3		%	+2.0		%	-5.1		%
Vinyls	+6.2		%	+9.3		%	+2.1		%	+9.7		%
Company average	+9.7		%	+12.6		%	+2.1		%	-0.7		%
	Three Months Ended September 30,						Nine Months Ended September 30,
	2013			2012			2013			2012
Average industry prices (1)
Ethane (cents/lb)	8.4			11.4			8.7			14.6
Propane (cents/lb)	24.4			21.2			22.2			24.7
Ethylene (cents/lb) (2)	54.3			52.1			58.7			57.8
Polyethylene (cents/lb) (3)	101.7			91.3			99.7			95.1
Styrene (cents/lb) (4)	83.2			77.7			83.6			75.3
Caustic soda ($/short ton) (5)	605.8			579.2			611.4			565.8
Chlorine ($/short ton) (6)	248.3			262.5			252.8			268.1
PVC (cents/lb) (7)	61.5			52.5			60.9			54.8

_____________

(1) Industry pricing data was obtained through IHS Chemical. We have not independently verified the data.

25

(2) Represents average North American spot prices of ethylene over the period as reported by IHS Chemical.

(3) Represents average North American contract prices of polyethylene low density film over the period as reported by IHS Chemical.

(4) Represents average North American contract prices of styrene over the period as reported by IHS Chemical.

(5) Represents average North American undiscounted contract prices of caustic soda over the period as reported by IHS Chemical.

(6) Represents average North American contract prices of chlorine (into chemicals) over the period as reported by IHS Chemical.

(7) Represents average North American contract prices of PVC over the period as reported by IHS Chemical.

Summary

For the quarter ended September 30, 2013, net income was $170.3 million, or $2.54 per diluted share, on net sales of $1,004.2 million. This represents an increase in net income of $83.3 million, or $1.24 per diluted share, compared to the quarter ended September 30, 2012 net income of $87.0 million, or $1.30 per diluted share, on net sales of $821.2 million. Net sales for the third quarter of 2013 increased by $183.0 million compared to net sales for the third quarter of 2012, mainly attributable to higher sales volumes for styrene and caustic, higher sales prices for most of our major products and sales contributed by our specialty PVC pipe business, which we acquired in May 2013. Income from operations was $266.6 million for the third quarter of 2013 as compared to $142.5 million for the third quarter of 2012. Income from operations for the third quarter of 2013 benefited primarily from improved olefins and vinyls integrated product margins, predominantly due to higher sales prices for most of our major products and lower overall feedstock costs as compared to the prior year period.

For the nine months ended September 30, 2013, net income was $439.5 million, or $6.54 per diluted share, on net sales of $2,807.9 million. This represents an increase in net income of $149.2 million, or $2.21 per diluted share, from the nine months ended September 30, 2012 net income of $290.3 million, or $4.33 per diluted share, on net sales of $2,770.0 million. Net sales for the nine months ended September 30, 2013 increased marginally by $37.9 million compared to the prior year period mainly due to higher sales volumes and sales prices for styrene, PVC resin and caustic, higher polyethylene sales prices and sales contributed by our specialty PVC pipe business, mostly offset by lower feedstock, ethylene and ethylene co-products sales volumes. Income from operations was $695.9 million for the nine months ended September 30, 2013 as compared to $459.1 million for the nine months ended September 30, 2012. The increase in income from operations was primarily attributable to higher olefins and vinyls integrated product margins, predominantly due to a significant decrease in feedstock costs as average industry ethane prices decreased 40.4% and average industry propane prices decreased 10.1% for the nine months ended September 30, 2013 as compared to the prior year period. The increase in income from operations was partially offset by the lost production and the unabsorbed fixed manufacturing costs and other costs associated with the turnaround and expansion of one of the Lake Charles, Louisiana ethylene units and the specialty PVC pipe business acquisition-related costs, including the effect of selling higher cost inventory recorded at fair value, of $5.8 million, or $0.06 per diluted share, after tax.

RESULTS OF OPERATIONS

Third Quarter 2013 Compared with Third Quarter 2012

Net Sales. Net sales increased by $183.0 million, or 22.3%, to $1,004.2 million in the third quarter of 2013 from $821.2 million in the third quarter of 2012, primarily attributable to higher sales volumes for styrene and caustic, higher sales prices for most of our major products and sales contributed by our specialty PVC pipe business. Average sales prices for the third quarter of 2013 increased by 9.7% as compared to the third quarter of 2012. Overall sales volumes increased by 12.6% as compared to the third quarter of 2012.

Gross Profit. Gross profit margin percentage increased to 30.3% for the third quarter of 2013 from 21.0% for the third quarter of 2012, driven mainly by improved olefins and vinyls integrated product margins, primarily attributable to higher sales prices for most of our major products and lower ethane costs, partially offset by higher propane costs. The third quarter 2013 gross profit margin also benefited from higher styrene and caustic sales volumes. Our raw material cost in both segments normally tracks industry prices, which experienced a decrease of 26.3% for ethane and an increase of 15.1% for propane, as compared to the third quarter of 2012. Sales prices increased an average of 9.7% for the third quarter of 2013 as compared to the third quarter of 2012. The gross profit margin for the third quarter of 2012 was negatively impacted by the unabsorbed fixed manufacturing costs associated with a planned outage of our styrene plant in Lake Charles.

Selling, General and Administrative Expenses. Selling, general and administrative expenses for the third quarter of 2013 of $37.9 million increased by $8.2 million as compared to the third quarter of 2012, mainly due to an increase in payroll and related labor costs, including incentive compensation, and an increase in selling expenses associated with the increase in sales.

26

Interest Expense. Interest expense decreased by $8.6 million to $3.3 million in the third quarter of 2013 from $11.9 million in the third quarter of 2012 largely as a result of increased capitalized interest on major capital projects as compared to the prior year period. Debt balances remained relatively unchanged from the prior year period.

Other (Expense) Income, Net. Other (expense) income, net was net expense of $0.3 million in the third quarter of 2013 compared to net income of $1.2 million in the third quarter of 2012, mainly due to lower investment income and related write-offs and lower interest income in the third quarter of 2013.

Income Taxes. The effective income tax rate was 35.3% for the third quarter of 2013. The effective income tax rate for the third quarter of 2013 was above the U.S. federal statutory rate of 35.0% primarily due to state income taxes, mostly offset by the domestic manufacturing deduction. The effective income tax rate was 30.5% for the third quarter of 2012. The effective income tax rate for the third quarter of 2012 was below the U.S. federal statutory rate of 35.0% primarily due to state tax credits, the domestic manufacturing deduction and a reduction in state income taxes.

Olefins Segment

Net Sales. Net sales increased by $139.5 million, or 25.8%, to $679.3 million in the third quarter of 2013 from $539.8 million in the third quarter of 2012, predominantly due to higher styrene sales volumes and higher sales prices for our major products as compared to the prior year period. Styrene sales volumes for the third quarter of 2012 were negatively impacted by a planned outage of our styrene plant in Lake Charles. Average sales prices for the Olefins segment increased by 11.5% in the third quarter of 2013 as compared to the third quarter of 2012. Average sales volumes for the Olefins segment increased by 14.3% in the third quarter of 2013 as compared to the third quarter of 2012.

Income from Operations. Income from operations increased by $112.7 million, or 90.5%, to $237.2 million in the third quarter of 2013 from $124.5 million in the third quarter of 2012. This increase was mainly attributable to higher olefins integrated product margins as compared to the prior year period, primarily as a result of higher sales prices for most of our major products and significantly lower feedstock costs. In addition, olefins integrated margins benefited from the increased ethylene production at our Lake Charles complex after the completion in the first quarter of 2013 of the expansion project to increase the ethane-based ethylene capacity of one of the ethylene units at that complex. Trading activity in the third quarter of 2013 resulted in a gain of $4.9 million as compared to a gain of $0.2 million in the third quarter of 2012. Third quarter 2012 income from operations was negatively impacted by the lost production and unabsorbed fixed manufacturing costs associated with the planned outage of our styrene plant in Lake Charles.

Vinyls Segment

Net Sales. Net sales increased by $43.4 million, or 15.4%, to $324.8 million in the third quarter of 2013 from $281.4 million in the third quarter of 2012. This increase was mainly attributable to higher caustic sales volume, higher PVC resin and caustic sales prices and the sales contributed by our specialty PVC pipe business. Average sales prices for the Vinyls segment increased by 6.2% in the third quarter of 2013 as compared to the third quarter of 2012. Average sales volumes for the Vinyls segment increased by 9.3% in the third quarter of 2013 as compared to the third quarter of 2012.

Income from Operations. Income from operations increased by $15.5 million, or 64.3%, to $39.6 million in the third quarter of 2013 from $24.1 million in the third quarter of 2012. This increase was primarily driven by higher vinyls integrated product margins, largely resulting from higher sales prices for all major products, higher caustic sales volume and improved operating rates as compared to the prior year period.

Nine Months Ended September 30, 2013 Compared with Nine Months Ended September 30, 2012

Net Sales. Net sales increased marginally by $37.9 million, or 1.4%, to $2,807.9 million for the nine months ended September 30, 2013 from $2,770.0 million for the nine months ended September 30, 2012, primarily attributable to higher sales volumes and sales prices for styrene, PVC resin and caustic, higher polyethylene sales prices and sales contributed by our specialty PVC pipe business, mostly offset by lower feedstock, ethylene and ethylene co-products sales volumes. Ethylene and ethylene co-product sales volumes were lower primarily due to the first quarter 2013 turnaround and expansion of one of the Lake Charles ethylene units. Average sales prices for the nine months ended September 30, 2013 increased by 2.1% as compared to the nine months ended September 30, 2012. Overall sales volumes for the nine months ended September 30, 2013 decreased by 0.7% as compared to the nine months ended September 30, 2012.

Gross Profit. Gross profit margin percentage of 28.7% for the nine months ended September 30, 2013 increased from the 19.7% gross profit margin percentage for the nine months ended September 30, 2012. The improvement in gross profit margin percentage was predominantly due to lower feedstock costs. Our raw material cost in both segments normally tracks industry prices, which experienced a decrease of 40.4% and 10.1% for ethane and propane, respectively, as compared to the nine months

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ended September 30, 2012. Sales prices increased an average of 2.1% for the nine months ended September 30, 2013 as compared to the prior year period.

Selling, General and Administrative Expenses. Selling, general and administrative expenses for the nine months ended September 30, 2013 increased by $22.3 million as compared to the nine months ended September 30, 2012, mainly attributable to an increase in payroll and related labor costs, including incentive compensation, and an increase in the provision for doubtful accounts.

Interest Expense. Interest expense decreased by $20.8 million to $14.9 million for the nine months ended September 30, 2013, largely due to increased capitalized interest on major capital projects and lower average interest rates in the first nine months of 2013 as compared to the prior year period. Debt balances remained relatively unchanged from the prior year period.

Other Income, Net. Other income, net decreased by $0.6 million to $3.1 million for the nine months ended September 30, 2013 from $3.7 million for the nine months ended September 30, 2012. The decrease was principally due to lower investment income and related write-offs, lower interest income and higher losses on foreign exchange as compared to the prior year period, mostly offset by the settlement of a claim against a supplier during the period.

Income Taxes. The effective income tax rate was 35.8% for the nine months ended September 30, 2013. The effective income tax rate for the 2013 period was above the U.S. federal statutory rate of 35.0% primarily due to state income taxes, partially offset by the domestic manufacturing deduction. The effective income tax rate was 33.5% for the nine months ended September 30, 2012. The effective income tax rate for the 2012 period was below the U.S. federal statutory rate of 35.0% primarily due to state tax credits and the domestic manufacturing deduction, partially offset by state income taxes.

Olefins Segment

Net Sales. Net sales decreased by $59.3 million, or 3.0%, to $1,885.5 million for the nine months ended September 30, 2013 from $1,944.8 million for the nine months ended September 30, 2012, mainly due to lower feedstock, ethylene and ethylene co-products sales volumes, partially offset by higher sales volumes for styrene and higher sales prices for polyethylene and styrene. Ethylene and ethylene co-product sales volumes were lower primarily due to the first quarter 2013 turnaround and expansion of one of the Lake Charles ethylene units. Average sales prices for the Olefins segment increased by 2.0% for the nine months ended September 30, 2013 as compared to the nine months ended September 30, 2012. Average sales volumes for the Olefins segment decreased by 5.1% for the nine months ended September 30, 2013 as compared to the nine months ended September 30, 2012.

Income from Operations. Income from operations increased by $176.4 million, or 43.1%, to $586.0 million for the nine months ended September 30, 2013 from $409.6 million for the nine months ended September 30, 2012. This increase was mainly attributable to higher olefins integrated product margins as compared to the prior year period. Margins improved primarily as a result of significantly lower feedstock costs. Income from operations for the nine months ended September 30, 2013 was negatively impacted by the lost production and the expensing of $19.9 million related to unabsorbed fixed manufacturing costs and other costs associated with the turnaround and expansion of one of the Lake Charles ethylene units. Trading activity for the nine months ended September 30, 2013 resulted in a gain of $9.9 million as compared to a loss of $0.8 million for the prior year period. Income from operations for the first nine months of 2012 was negatively impacted by the lost production and unabsorbed fixed manufacturing costs associated with the planned outage of our Lake Charles styrene plant.

Vinyls Segment

Net Sales. Net sales increased by $97.1 million, or 11.8%, to $922.3 million for the nine months ended September 30, 2013 from $825.2 million for the nine months ended September 30, 2012. This increase was primarily attributable to higher sales volumes for caustic and PVC resin, higher sales prices for most major products and sales contributed by our specialty PVC pipe business. Sales volumes for the first nine months of 2012 were negatively impacted by the lower operating rates at our Geismar vinyls complex as a result of operational issues related to the unscheduled shut down at the complex. Average sales prices for the Vinyls segment increased by 2.1% for the nine months ended September 30, 2013 as compared to the nine months ended September 30, 2012, while average sales volumes increased by 9.7% for the nine months ended September 30, 2013 as compared to the nine months ended September 30, 2012.

Income from Operations. Income from operations increased by $68.4 million to $136.1 million for the nine months ended September 30, 2013 from $67.7 million for the nine months ended September 30, 2012. This increase was predominantly driven by lower feedstock costs, higher sales volumes for caustic and PVC resin and higher operating rates as compared to the prior year period, partially offset by the specialty PVC pipe business acquisition-related costs, including the effect of selling higher cost inventory recorded at fair value. The Vinyls segment's operating results for the first nine months of 2012 were

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negatively impacted by the lost production, lost sales and unabsorbed manufacturing and other costs associated with the unscheduled shut down at our Geismar vinyls complex.

CASH FLOW DISCUSSION FOR THE NINE MONTHS ENDED SEPTEMBER 30, 2013 AND 2012

Cash Flows

Operating Activities

Operating activities provided cash of $547.5 million in the first nine months of 2013 compared to cash provided of $492.8 million in the first nine months of 2012. The $54.7 million increase in cash flows from operating activities was mainly due to an increase in income from operations, partially offset by an increase in the use of cash for working capital purposes and deferred turnaround costs from the turnaround of one of our Lake Charles ethylene units. Income from operations increased by $236.8 million in the first nine months of 2013 primarily as a result of higher olefins and vinyls integrated product margins as compared to the prior year period. Changes in components of working capital, which we define for purposes of this cash flow discussion as accounts receivable, net, inventories, prepaid expenses and other current assets, less accounts payable and accrued liabilities, used cash of $46.5 million in the first nine months of 2013, compared to $115.3 million of cash provided in the first nine months of 2012, an unfavorable change of $161.8 million. The change was caused by higher accounts receivable balances largely attributable to an increase in average sales volumes during the third quarter of 2013 as compared to the third quarter of 2012 and an increase in inventory during the 2013 period.

Investing Activities

Net cash used for investing activities during the first nine months of 2013 was $694.6 million as compared to net cash used for investing activities of $194.6 million in the first nine months of 2012. Capital expenditures were $498.3 million in the first nine months of 2013 compared to $235.5 million in the first nine months of 2012. The higher capital expenditures in the first nine months of 2013 were largely attributable to the construction of the new chlor-alkali plant at our Geismar facility (which is expected to be operational by the end of 2013), the feedstock conversion, PVC plant expansion and ethylene furnaces modernization projects at our Calvert City, Kentucky complex and the expansion of one of the ethylene units at our Lake Charles complex. Capital expenditures in the first nine months of 2012 were mainly incurred on the construction of the new Geismar chlor-alkali plant and the expansion of one of the ethylene units at our Lake Charles complex. The remaining capital expenditures in the first nine months of 2013 and 2012 primarily related to projects to improve production capacity or reduce costs and maintenance, safety and environmental projects at our various facilities. We used $178.3 million of cash to acquire our specialty PVC pipe business. Purchases of securities in the first nine months of 2013 totaled $232.3 million and were comprised of short-term commercial paper and corporate and U.S. government debt securities. We also received aggregate proceeds of $239.8 million from the maturities of short-term commercial paper in the first nine months of 2013. The activity during the first nine months of 2012 was primarily related to the proceeds received from the sale of equity securities.

Financing Activities

Net cash used for financing activities during the first nine months of 2013 was $51.4 million as compared to net cash provided of $74.3 million in the first nine months of 2012. The activity during the first nine months of 2013 was primarily related to the $40.2 million payment of cash dividends and $19.4 million of cash used for the repurchase of shares of our common stock, partially offset by proceeds of $3.2 million from the exercise of stock options. The activity during the first nine months of 2012 was mainly related to the draw-down of our restricted cash and proceeds from the exercise of stock options, partially offset by the $22.3 million payment of cash dividends, $10.8 million of repurchases of shares of our common stock and $2.2 million of debt issuance costs associated with the issuance of our 3.60% senior notes due 2022.

LIQUIDITY AND CAPITAL RESOURCES

Liquidity and Financing Arrangements

Our principal sources of liquidity are from cash and cash equivalents, investments in current marketable securities, cash from operations, short-term borrowings under our revolving credit facility and our long-term financing.

In October 2012, we announced a project to convert the feedstock for our Calvert City ethylene plant from propane to ethane and the planned increase in ethylene capacity from 450 million pounds annually to 630 million pounds annually. The ethylene expansion and feedstock conversion project is targeted for start-up in the second quarter of 2014. In addition, we announced an expansion of the existing PVC plant in Calvert City, which should allow us to take advantage of the increased ethylene production at our Calvert City complex and to provide additional PVC resin to meet the growing demands of our global customers. The expansion of the Calvert City PVC plant is expected to increase PVC resin capacity by approximately

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200 million pounds annually and is targeted for completion by the second half of 2014. These projects are currently estimated to cost in the range of $210.0 million to $240.0 million in the aggregate.

In August 2010, we announced that we intend to proceed with the previously announced plans for the construction of a new chlor-alkali plant at our Geismar facility. The project is currently estimated to cost in the range of $400.0 million to $425.0 million and is targeted for start-up in the fourth quarter of 2013.

These capital projects are expected to be funded with cash on hand, cash flow from operations, and, if necessary, borrowings under our revolving credit facility and other external financing. As of September 30, 2013, we had incurred a total cost of approximately $465.3 million on these capital projects.

In April 2011, we announced an expansion program to increase the ethane-based ethylene capacity of both of the ethylene units at our Lake Charles complex. We completed the expansion of the first ethylene unit in the first quarter of 2013. We are evaluating plans for the expansion of the second ethylene unit at our Lake Charles complex in 2015.

In August 2011, our Board of Directors authorized a stock repurchase program totaling $100.0 million. As of September 30, 2013, we had repurchased 506,525 shares of our common stock for an aggregate purchase price of approximately $32.7 million under this program. During the three months ended September 30, 2013, we repurchased 59,700 shares of our common stock for an aggregate purchase price of approximately $6.1 million under this program. Purchases under this program may be made either through the open market or in privately negotiated transactions. Decisions regarding the amount and the timing of purchases under the program will be influenced by our cash on hand, our cash flow from operations, general market conditions and other factors. The program may be discontinued by our Board of Directors at any time.

We believe that our sources of liquidity as described above will be adequate to fund our normal operations and ongoing capital expenditures. Funding of any potential large expansions or any potential acquisitions may depend on our ability to obtain additional financing in the future. We may not be able to access additional liquidity at cost effective interest rates due to the volatility of the commercial credit markets.

Cash, Cash Equivalents and Current Marketable Securities

As of September 30, 2013, our cash, cash equivalents and current marketable securities totaled $717.2 million. In addition, we have a revolving credit facility available to supplement cash if needed, as described under "Debt" below.

Debt

As of September 30, 2013, our long-term debt, including current maturities, totaled $763.8 million, consisting of $250.0 million principal amount of 3.60% senior notes due 2022 (less the unamortized discount of $1.1 million), $100.0 million of 6 ½% senior notes due 2029, $250.0 million of 6 ¾% senior notes due 2032, $89.0 million of 6 ½% senior notes due 2035 (the "6 ½% GO Zone Senior Notes Due 2035"), $65.0 million of 6 ½% senior notes due 2035 (the "6 ½% IKE Zone Senior Notes Due 2035") (collectively, but excluding the 3.60% senior notes due 2022, the "Senior Notes") and a $10.9 million loan from the proceeds of tax-exempt waste disposal revenue bonds (supported by an $11.3 million letter of credit). The 6 ½% senior notes due 2029, the 6 ¾% senior notes due 2032, the 6 ½% GO Zone Senior Notes Due 2035 and the 6 ½% IKE Zone Senior Notes Due 2035 evidence and secure our obligations to the Louisiana Local Government Environmental Facility and Development Authority (the "Authority"), a political subdivision of the State of Louisiana, under four loan agreements relating to the issuance of $100.0 million, $250.0 million, $89.0 million and $65.0 million aggregate principal amount of the Authority's tax-exempt revenue bonds, respectively. As of September 30, 2013, debt outstanding under the tax-exempt waste disposal revenue bonds bore interest at a variable rate. As of September 30, 2013, we were in compliance with all of the covenants with respect to the 3.60% senior notes due 2022, the Senior Notes, our waste disposal revenue bonds and our revolving credit facility.

Revolving Credit Facility

We have a $400.0 million senior secured revolving credit facility. The facility includes a provision permitting us to increase the size of the facility, up to four times, in increments of at least $25.0 million each (up to a maximum of $150.0 million) under certain circumstances if certain lenders agree to commit to such an increase.

At September 30, 2013, we had no borrowings outstanding under the revolving credit facility. Any borrowings under the facility will bear interest at either LIBOR plus a spread ranging from 1.75% to 2.25% or a base rate plus a spread ranging from 0.25% to 0.75%. The revolving credit facility also requires an unused commitment fee of 0.375% per annum. All interest rates under the facility are subject to monthly grid pricing adjustments based on prior month average daily loan availability. The revolving credit facility matures on September 16, 2016. As of September 30, 2013, we had outstanding letters of credit totaling $16.9 million and borrowing availability of $383.1 million under the revolving credit facility.

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Our revolving credit facility requires us to maintain a minimum fixed charge coverage ratio of 1.0:1 for successive 30-day periods after any date on which the borrowing availability under the facility is less than the greater of (1) 12.5% of the commitments under the facility and (2) $50.0 million, until the borrowing availability exceeds the greater of the amount in clause (1) and the amount in clause (2) for a 30-day period.

In order to make acquisitions or investments, our revolving credit facility provides that (1) we must maintain a minimum borrowing availability of at least the greater of $100.0 million or 25% of the total bank commitments under our revolving credit facility or (2) we must maintain a minimum borrowing availability of at least the greater of $70.0 million or 17.5% of the total bank commitments under our revolving credit facility and meet a minimum fixed charge coverage ratio of 1.0:1 under our revolving credit facility. However, we may make specified distributions up to an aggregate of $25.0 million and specified acquisitions up to an aggregate of $25.0 million if either we maintain a minimum borrowing availability of at least the greater of $70.0 million or 17.5% of the total bank commitments under our revolving credit facility or we meet the minimum fixed charge coverage ratio of 1.0:1 under our revolving credit facility. Notwithstanding the foregoing, we may make (1) investments up to $200.0 million in one or more joint ventures that own feedstock, raw material and ethylene pipeline, storage and fractionating facilities and (2) additional investments up to $55.0 million in Suzhou Huasu Plastics Co., Ltd. The revolving credit facility contains other customary covenants and events of default that impose significant operating and financial restrictions on us. These restrictions, among other things, provide limitations on the occurrence of additional indebtedness and our ability to create liens, to engage in certain affiliate transactions and to engage in sale-leaseback transactions. See "Management's Discussion and Analysis of Financial Condition and Results of Operations—Liquidity and Capital Resources—Debt" in the 2012 Form 10-K for more information on the revolving credit facility.

GO Zone and IKE Zone Bonds

As of September 30, 2013, we had drawn all the proceeds from the issuance of the 6 ½% senior notes due 2029, 6 ¾% senior notes due 2032, 6 ½% GO Zone Senior Notes Due 2035 and 6 ½% IKE Zone Senior Notes Due 2035. See "Management's Discussion and Analysis of Financial Condition and Results of Operations—Liquidity and Capital Resources—Debt" in the 2012 Form 10-K for more information on the 6 ½% senior notes due 2029, the 6 ¾% senior notes due 2032, the 6 ½% GO Zone Senior Notes Due 2035 and the 6 ½% IKE Zone Senior Notes Due 2035. All domestic restricted subsidiaries that guarantee other debt of ours or of another guarantor of the Senior Notes in excess of $5.0 million are guarantors of these notes.

The indentures governing the Senior Notes contain customary covenants and events of default. Accordingly, these agreements generally impose significant operating and financial restrictions on us. These restrictions, among other things, provide limitations on incurrence of additional indebtedness, the payment of dividends, certain investments and acquisitions and sales of assets. However, the effectiveness of certain of these restrictions is currently suspended because the Senior Notes are currently rated investment grade by at least two nationally recognized credit rating agencies. The most significant of these provisions, if it were currently effective, would restrict us from incurring additional debt, except specified permitted debt (including borrowings under our credit facility), when our fixed charge coverage ratio is below 2.0:1. These limitations are subject to a number of important qualifications and exceptions, including, without limitation, an exception for the payment of our regular quarterly dividend of up to $0.20 per share (currently $0.2250 per share). If the restrictions were currently effective, distributions in excess of $100.0 million would not be allowed unless, after giving pro forma effect to the distribution, our fixed charge coverage ratio is at least 2.0:1 and such payment, together with the aggregate amount of all other distributions after January 13, 2006, is less than the sum of 50% of our consolidated net income for the period from October 1, 2003 to the end of the most recent quarter for which financial statements have been filed, plus 100% of net cash proceeds received after October 1, 2003 as a contribution to our common equity capital or from the issuance or sale of certain securities, plus several other adjustments.

3.60% Senior Notes due 2022

The 3.60% senior notes due 2022 are unsecured and were issued with an original issue discount of $1.2 million. There is no sinking fund and no scheduled amortization of the 3.60% senior notes due 2022 prior to maturity. See "Management's Discussion and Analysis of Financial Condition and Results of Operations—Liquidity and Capital Resources—Debt" in the 2012 Form 10-K for more information on the 3.60% senior notes due 2022. All of our domestic subsidiaries that guarantee other indebtedness of ours or of another guarantor of the 3.60% senior notes due 2022 in excess of $5.0 million are guarantors of the 3.60% senior notes due 2022.

The indenture governing the 3.60% senior notes due 2022 contains customary events of default and covenants that will restrict our and certain of our subsidiaries' ability to (1) incur certain secured indebtedness, (2) engage in certain sale-leaseback transactions and (3) consolidate, merge or transfer all or substantially all of our assets.

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Revenue Bonds

In December 1997, we entered into a loan agreement with a public trust established for public purposes for the benefit of the Parish of Calcasieu, Louisiana. The public trust issued $10.9 million principal amount of tax-exempt waste disposal revenue bonds in order to finance our construction of waste disposal facilities for an ethylene plant. The waste disposal revenue bonds expire in December 2027 and are subject to redemption and mandatory tender for purchase prior to maturity under certain conditions. Interest on the waste disposal revenue bonds accrues at a rate determined by a remarketing agent and is payable quarterly.

Our ability to make payments on our indebtedness and to fund planned capital expenditures will depend on our ability to generate cash in the future, which is subject to general economic, financial, competitive, legislative, regulatory and other factors that are beyond our control. Based on our current level of operations, we believe our cash flow from operations, available cash and available borrowings under our revolving credit facility will be adequate to meet our normal operating needs for the foreseeable future.

Off-Balance Sheet Arrangements

None.

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 report are forward-looking statements. All statements, other than statements of historical facts, included in this report 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 and feedstock conversion 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;

• 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;

• 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. These statements are subject to a number of assumptions, risks and uncertainties, including those described in "Risk Factors" in the 2012 Form 10-K and the following:

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• 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 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 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 statements.

Item 3. Quantitative and Qualitative Disclosures about Market Risk

Commodity Price Risk

A substantial portion of our products and raw materials are commodities whose prices fluctuate as market supply and demand fundamentals change. Accordingly, product margins and the level of our profitability tend to fluctuate with changes in the business cycle. We try to protect against such instability through various business strategies. Our strategies include ethylene feedstock flexibility and moving downstream into the olefins and vinyls products where pricing is more stable. We use derivative instruments in certain instances to reduce price volatility risk on feedstocks and products. Based on our open derivative positions at September 30, 2013, a hypothetical $0.10 increase in the price of a gallon of ethane would have increased our income before taxes by $2.4 million and a hypothetical $0.10 increase in the price of a pound of ethylene would have decreased our income before taxes by $3.9 million. Additional information concerning derivative commodity instruments appears in Notes 9 and 10 to the unaudited consolidated financial statements within this Quarterly Report on Form 10-Q.

Interest Rate Risk

We are exposed to interest rate risk with respect to fixed and variable rate debt. At September 30, 2013, we had variable rate debt of $10.9 million outstanding. All of the debt outstanding under our revolving credit facility (none was outstanding at September 30, 2013) and our loan relating to the tax-exempt waste disposal revenue bonds are at variable rates. We do not currently hedge our variable interest rate debt, but we may do so in the future. The average variable interest rate for our variable rate debt of $10.9 million as of September 30, 2013 was 0.16%. A hypothetical 100 basis point increase in the average interest rate on our variable rate debt would increase our annual interest expense by approximately $0.1 million. Also, at September 30, 2013, we had $754.0 million aggregate principal amount of fixed rate debt. We are subject to the risk of higher interest cost if and when this debt is refinanced. If interest rates are 1% higher at the time of refinancing, our annual interest expense would increase by approximately $7.5 million.

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Item 4. Controls and Procedures

We carried out an evaluation, under the supervision and with the participation of our management, including our President and Chief Executive Officer and our Senior Vice President, Chief Financial Officer and Treasurer, of the effectiveness of our disclosure controls and procedures pursuant to Rules 13a-15 or 15d-15 under the Securities Exchange Act of 1934 as of the end of the period covered by this report. Based upon that evaluation, our President and Chief Executive Officer and our Senior Vice President, Chief Financial Officer and Treasurer concluded that our disclosure controls and procedures are effective with respect to (i) the accumulation and communication to our management, including our Chief Executive Officer and our Chief Financial Officer, of information required to be disclosed by us in the reports that we submit under the Exchange Act, and (ii) the recording, processing, summarizing and reporting of such information within the time periods specified in the SEC's rules and forms.

There were no changes in our internal control over financial reporting that occurred during the three months ended September 30, 2013 that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.

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PART II. OTHER INFORMATION

Item 1. Legal Proceedings

The 2012 Form 10-K, filed on February 22, 2013, contained a description of various legal proceedings in which we are involved, including environmental proceedings at our facilities in Calvert City. See Note 16 to the unaudited consolidated financial statements within this Quarterly Report on Form 10-Q for a description of certain of those proceedings, which information is incorporated by reference herein.

Item 1A. Risk Factors

For a discussion of risk factors, please read Item 1A, "Risk Factors" in the 2012 Form 10-K and in our Quarterly Report on Form 10-Q for the quarter ended March 31, 2013. There have been no material changes from those risk factors.

Item 2. Unregistered Sales of Equity Securities and Use of Proceeds

The following table provides information on our purchase of equity securities during the quarter ended September 30, 2013:

Period	Total Number of Shares Purchased (1)	Average Price Paid Per Share		Total Number of Shares Purchased as Part of Publicly Announced Plans or Programs (1)	Maximum Number (or Approximate Dollar Value) of Shares that May Yet Be Purchased Under the Plans or Programs (1)
July 2013	—	$	—	—	$	73,415,000
August 2013	—	$	—	—	$	73,415,000
September 2013	59,700	$	102.62	59,700	$	67,289,000
	59,700	$	102.62	59,700

_____________

(1) On August 22, 2011, we announced the authorization by our Board of Directors of a $100.0 million stock repurchase program. As of September 30, 2013, 506,525 shares of common stock had been acquired at an aggregate purchase price of $32.7 million. Decisions regarding the amount and the timing of purchases under the program will be influenced by our cash on hand, our cash flow from operations, general market conditions and other factors. The program may be discontinued by our Board of Directors at any time.

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Item 6. Exhibits

Exhibit No.
31.1	Rule 13a – 14(a) / 15d – 14(a) Certification (Principal Executive Officer)
31.2	Rule 13a – 14(a) / 15d – 14(a) Certification (Principal Financial Officer)
32.1	Section 1350 Certification (Principal Executive Officer and Principal Financial Officer)
101.INS	XBRL Instance Document
101.SCH	XBRL Taxonomy Extension Schema Document
101.CAL	XBRL Taxonomy Extension Calculation Linkbase Document
101.DEF	XBRL Taxonomy Extension Definition Linkbase Document
101.LAB	XBRL Taxonomy Extension Label Linkbase Document
101.PRE	XBRL Taxonomy Extension Presentation Linkbase Document

36

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

		WESTLAKE CHEMICAL CORPORATION
Date:	November 7, 2013	By:	/S/    ALBERT CHAO
			Albert Chao
			President and Chief Executive Officer (Principal Executive Officer)
Date:	November 7, 2013	By:	/S/    M. STEVEN BENDER
			M. Steven Bender
			Senior Vice President, Chief Financial Officer and Treasurer (Principal Financial Officer)

37

EX-31.1

Exhibit 31.1

CERTIFICATIONS

I, Albert Chao, certify that:

1. I have reviewed this Quarterly Report on Form 10-Q of Westlake Chemical Corporation;

2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3. Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4. The registrant's other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

a) designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b) designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

c) evaluated the effectiveness of the registrant's disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

d) disclosed in this report any change in the registrant's internal control over financial reporting that occurred during the registrant's most recent fiscal quarter (the registrant's fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant's internal control over financial reporting; and

5. The registrant's other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant's auditors and the audit committee of registrant's board of directors (or persons performing the equivalent functions):

a) all significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant's ability to record, process, summarize and report financial information; and

b) any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant's internal control over financial reporting.

Date:	November 7, 2013	/S/    ALBERT CHAO
		Albert Chao
		President and Chief Executive Officer (Principal Executive Officer)

EX-31.2

Exhibit 31.2

CERTIFICATIONS

I, M. Steven Bender, certify that:

1. I have reviewed this Quarterly Report on Form 10-Q of Westlake Chemical Corporation;

2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3. Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4. The registrant's other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

a) designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b) designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

c) evaluated the effectiveness of the registrant's disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

d) disclosed in this report any change in the registrant's internal control over financial reporting that occurred during the registrant's most recent fiscal quarter (the registrant's fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant's internal control over financial reporting; and

5. The registrant's other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant's auditors and the audit committee of registrant's board of directors (or persons performing the equivalent functions):

a) all significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant's ability to record, process, summarize and report financial information; and

b) any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant's internal control over financial reporting.

Date:	November 7, 2013	/S/ M. STEVEN BENDER
		M. Steven Bender
		Senior Vice President, Chief Financial Officer and Treasurer (Principal Financial Officer)

EX-32.1

Exhibit 32.1

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of Westlake Chemical Corporation (the "Company") on Form 10-Q for the fiscal quarter ended September 30, 2013 as filed with the Securities and Exchange Commission on the date hereof (the "Report"), I, Albert Chao, President and Chief Executive Officer of the Company, and I, M. Steven Bender, Senior Vice President, Chief Financial Officer and Treasurer of the Company, certify, to the best of our knowledge, pursuant to 18 U.S.C. §1350, as adopted pursuant to §906 of the Sarbanes-Oxley Act of 2002, that:

(1) The Report fully complies with the requirements of section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

(2) The information contained in the Report fairly presents, in all material aspects, the financial condition and results of operations of the Company.

Date:	November 7, 2013	/S/    ALBERT CHAO
		Albert Chao
		President and Chief Executive Officer (Principal Executive Officer)
Date:	November 7, 2013	/S/    M. STEVEN BENDER
		M. Steven Bender
		Senior Vice President, Chief Financial Officer and Treasurer (Principal Financial Officer)

XML

Guarantor Disclosures (Condensed Consolidating Financial Information Balance Sheets) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2011
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	$ 591,556	$ 790,078	$ 1,198,468	$ 825,901
Marketable Securities, Current	125,597	124,873
Accounts receivable, net	433,025	400,159
Inventories	451,571	399,298
Prepaid expenses and other current assets	18,809	14,700
Deferred income taxes	22,293	22,305
Total current assets	1,642,851	1,751,413
Property, plant and equipment, net	1,952,918	1,510,048
Equity investments	65,488	43,736
Other assets, net	262,192	106,999
Total assets	3,923,449	3,412,196
Accounts payable	258,067	217,050
Accrued liabilities	174,619	181,460
Total current liabilities	432,686	398,510
Long-term debt	763,849	763,761
Deferred income taxes	410,166	326,290
Other liabilities	51,691	51,379
Stockholders' equity	2,265,057	1,872,256
Total liabilities and stockholders' equity	3,923,449	3,412,196
Westlake Chemical Corporation
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	560,261	753,881	1,168,124	803,320
Marketable Securities, Current	125,597	124,873
Accounts receivable, net	5,373	7,933
Inventories	0	0
Prepaid expenses and other current assets	468	389
Deferred income taxes	431	431
Total current assets	692,130	887,507
Property, plant and equipment, net	0	0
Equity investments	2,635,954	3,018,926
Other assets, net	16,969	17,033
Total assets	3,345,053	3,923,466
Accounts payable	311,357	1,285,530
Accrued liabilities	15,679	12,808
Total current liabilities	327,036	1,298,338
Long-term debt	752,960	752,872
Deferred income taxes	0	0
Other liabilities	0	0
Stockholders' equity	2,265,057	1,872,256
Total liabilities and stockholders' equity	3,345,053	3,923,466
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	4,494	6,973	5,693	2,517
Marketable Securities, Current	0	0
Accounts receivable, net	694,473	1,675,274
Inventories	435,540	385,140
Prepaid expenses and other current assets	15,931	11,386
Deferred income taxes	21,744	21,581
Total current assets	1,172,182	2,100,354
Property, plant and equipment, net	1,945,405	1,502,902
Equity investments	98,823	65,448
Other assets, net	251,703	94,678
Total assets	3,468,113	3,763,382
Accounts payable	220,106	192,443
Accrued liabilities	151,654	178,915
Total current liabilities	371,760	371,358
Long-term debt	10,889	10,889
Deferred income taxes	416,404	331,320
Other liabilities	51,640	51,312
Stockholders' equity	2,617,420	2,998,503
Total liabilities and stockholders' equity	3,468,113	3,763,382
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	26,801	29,224	24,651	20,064
Marketable Securities, Current	0	0
Accounts receivable, net	5,489	2,959
Inventories	16,031	14,158
Prepaid expenses and other current assets	2,410	2,925
Deferred income taxes	118	293
Total current assets	50,849	49,559
Property, plant and equipment, net	7,513	7,146
Equity investments	31,634	32,923
Other assets, net	506	1,252
Total assets	90,502	90,880
Accounts payable	4,322	13,969
Accrued liabilities	1,878	852
Total current liabilities	6,200	14,821
Long-term debt	0	0
Deferred income taxes	748	934
Other liabilities	51	67
Stockholders' equity	83,503	75,058
Total liabilities and stockholders' equity	90,502	90,880
Eliminations
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	0	0	0	0
Marketable Securities, Current	0	0
Accounts receivable, net	(272,310)	(1,286,007)
Inventories	0	0
Prepaid expenses and other current assets	0	0
Deferred income taxes	0	0
Total current assets	(272,310)	(1,286,007)
Property, plant and equipment, net	0	0
Equity investments	(2,700,923)	(3,073,561)
Other assets, net	(6,986)	(5,964)
Total assets	(2,980,219)	(4,365,532)
Accounts payable	(277,718)	(1,274,892)
Accrued liabilities	5,408	(11,115)
Total current liabilities	(272,310)	(1,286,007)
Long-term debt	0	0
Deferred income taxes	(6,986)	(5,964)
Other liabilities	0	0
Stockholders' equity	(2,700,923)	(3,073,561)
Total liabilities and stockholders' equity	$ (2,980,219)	$ (4,365,532)

XML

Guarantor Disclosures (Condensed Consolidating Financial Information Statement of Cash Flows) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Condensed Financial Statements, Captions [Line Items]
Net income	$ 439,453	$ 290,278
Depreciation and amortization	117,387	110,750
Deferred income taxes	83,443	4,385
Net changes in working capital and other	(92,783)	87,418
Net cash provided by operating activities	547,500	492,831
Acquisition of business	(178,309)	0
Additions to equity investments	(23,338)	0
Additions to property, plant and equipment	(498,290)	(235,463)
Construction of assets pending sale-leaseback	(136)	(5,484)
Proceeds from disposition of assets	78	435
Proceeds from repayment of loan to affiliate	167	763
Proceeds from sales of equity securities	239,764	47,655
Purchase of securities and other investments	(232,286)	(2,961)
Settlements of derivative instruments	(2,297)	471
Net cash used for investing activities	(694,647)	(194,584)
Intercompany financing	0	0
Capitalized debt issuance costs	0	(2,221)
Dividends paid	(40,204)	(22,345)
Proceeds from Issuance of Long-term Debt	0	248,818
Proceeds from exercise of stock options	3,182	6,627
Repayments of Long-term Debt	0	(250,000)
Repurchase of common stock for treasury	(19,409)	(10,784)
Utilization of restricted cash	0	96,433
Windfall tax benefits from share-based payment arrangements	5,056	7,792
Net cash provided by financing activities	(51,375)	74,320
Net increase in cash and cash equivalents	(198,522)	372,567
Cash and cash equivalents at beginning of period	790,078	825,901
Cash and cash equivalents at end of period	591,556	1,198,468
Westlake Chemical Corporation
Condensed Financial Statements, Captions [Line Items]
Net income	439,453	290,278
Depreciation and amortization	1,094	1,149
Deferred income taxes	(1,102)	(176)
Net changes in working capital and other	(458,336)	(317,955)
Net cash provided by operating activities	(18,891)	(26,704)
Acquisition of business	0
Additions to equity investments	0
Additions to property, plant and equipment	0	0
Construction of assets pending sale-leaseback	0	0
Proceeds from disposition of assets	0	0
Proceeds from repayment of loan to affiliate	0	0
Proceeds from sales of equity securities	239,764	3
Purchase of securities and other investments	(232,286)	0
Settlements of derivative instruments	0	0
Net cash used for investing activities	7,478	3
Intercompany financing	(130,832)	317,185
Capitalized debt issuance costs		(2,221)
Dividends paid	(40,204)	(22,345)
Proceeds from Issuance of Long-term Debt		248,818
Proceeds from exercise of stock options	3,182	6,627
Repayments of Long-term Debt		(250,000)
Repurchase of common stock for treasury	(19,409)	(10,784)
Utilization of restricted cash		96,433
Windfall tax benefits from share-based payment arrangements	5,056	7,792
Net cash provided by financing activities	(182,207)	391,505
Net increase in cash and cash equivalents	(193,620)	364,804
Cash and cash equivalents at beginning of period	753,881	803,320
Cash and cash equivalents at end of period	560,261	1,168,124
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net income	446,858	312,038
Depreciation and amortization	114,432	107,191
Deferred income taxes	84,532	3,932
Net changes in working capital and other	(87,330)	95,909
Net cash provided by operating activities	558,492	519,070
Acquisition of business	(178,309)
Additions to equity investments	(23,338)
Additions to property, plant and equipment	(496,027)	(234,713)
Construction of assets pending sale-leaseback	(136)	(5,484)
Proceeds from disposition of assets	6	414
Proceeds from repayment of loan to affiliate	0	0
Proceeds from sales of equity securities	0	47,652
Purchase of securities and other investments	0	(2,961)
Settlements of derivative instruments	(2,297)	471
Net cash used for investing activities	(700,101)	(194,621)
Intercompany financing	139,130	(321,273)
Capitalized debt issuance costs		0
Dividends paid	0	0
Proceeds from Issuance of Long-term Debt		0
Proceeds from exercise of stock options	0	0
Repayments of Long-term Debt		0
Repurchase of common stock for treasury	0	0
Utilization of restricted cash		0
Windfall tax benefits from share-based payment arrangements	0	0
Net cash provided by financing activities	139,130	(321,273)
Net increase in cash and cash equivalents	(2,479)	3,176
Cash and cash equivalents at beginning of period	6,973	2,517
Cash and cash equivalents at end of period	4,494	5,693
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net income	(1,639)	(676)
Depreciation and amortization	1,861	2,410
Deferred income taxes	13	629
Net changes in working capital and other	7,664	(1,898)
Net cash provided by operating activities	7,899	465
Acquisition of business	0
Additions to equity investments	0
Additions to property, plant and equipment	(2,263)	(750)
Construction of assets pending sale-leaseback	0	0
Proceeds from disposition of assets	72	21
Proceeds from repayment of loan to affiliate	167	763
Proceeds from sales of equity securities	0	0
Purchase of securities and other investments	0	0
Settlements of derivative instruments	0	0
Net cash used for investing activities	(2,024)	34
Intercompany financing	(8,298)	4,088
Capitalized debt issuance costs		0
Dividends paid	0	0
Proceeds from Issuance of Long-term Debt		0
Proceeds from exercise of stock options	0	0
Repurchase of common stock for treasury	0	0
Utilization of restricted cash		0
Windfall tax benefits from share-based payment arrangements	0	0
Net cash provided by financing activities	(8,298)	4,088
Net increase in cash and cash equivalents	(2,423)	4,587
Cash and cash equivalents at beginning of period	29,224	20,064
Cash and cash equivalents at end of period	26,801	24,651
Eliminations
Condensed Financial Statements, Captions [Line Items]
Net income	(445,219)	(311,362)
Depreciation and amortization	0	0
Deferred income taxes	0	0
Net changes in working capital and other	445,219	311,362
Net cash provided by operating activities	0	0
Acquisition of business	0
Additions to equity investments	0
Additions to property, plant and equipment	0	0
Construction of assets pending sale-leaseback	0	0
Proceeds from disposition of assets	0	0
Proceeds from repayment of loan to affiliate	0	0
Proceeds from sales of equity securities	0	0
Purchase of securities and other investments	0	0
Settlements of derivative instruments	0	0
Net cash used for investing activities	0	0
Intercompany financing	0	0
Capitalized debt issuance costs		0
Dividends paid	0	0
Proceeds from Issuance of Long-term Debt		0
Proceeds from exercise of stock options	0	0
Repayments of Long-term Debt		0
Repurchase of common stock for treasury	0	0
Utilization of restricted cash		0
Windfall tax benefits from share-based payment arrangements	0	0
Net cash provided by financing activities	0	0
Net increase in cash and cash equivalents	0	0
Cash and cash equivalents at beginning of period	0	0
Cash and cash equivalents at end of period	$ 0	$ 0

XML

Income Taxes

9 Months Ended

Sep. 30, 2013

Income Tax Disclosure [Abstract]

Income Taxes

Income Taxes

The effective income tax rate was 35.8% for the nine months ended September 30, 2013. The effective income tax rate for the 2013 period was above the U.S. federal statutory rate of 35.0% primarily due to state income taxes, partially offset by the domestic manufacturing deduction. The effective income tax rate was 33.5% for the nine months ended September 30, 2012. The effective income tax rate for the 2012 period was below the U.S. federal statutory rate of 35.0% primarily due to state tax credits and the domestic manufacturing deduction, partially offset by state income taxes.

There was no material change to the total gross unrecognized tax benefits for the nine months ended September 30, 2013. Management anticipates reductions to the total amount of unrecognized tax benefits of an additional $621 within the next twelve months due to expiring statutes of limitations.

The Company recognizes penalties and interest accrued related to unrecognized tax benefits in income tax expense. As of September 30, 2013, the Company had no material accrued interest and penalties related to uncertain tax positions.

The Company files income tax returns in the U.S. federal jurisdiction, various states and foreign jurisdictions. The Company is no longer subject to examinations by tax authorities before the year 2007.

XML

Derivative Instruments (Textual) (Detail) (Commodity Forward Contracts, Designated As Fair Value Hedges)	Sep. 30, 2013 gal
Commodity Forward Contracts | Designated As Fair Value Hedges
Derivative [Line Items]
Feedstock forward contracts, in gallons	10,710,000

XML

Consolidated Statements of Operations (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Income Statement [Abstract]
Net sales	$ 1,004,165	$ 821,175	$ 2,807,859	$ 2,770,000
Cost of sales	699,694	648,996	2,002,092	2,223,288
Gross profit	304,471	172,179	805,767	546,712
Selling, general and administrative expenses	37,869	29,662	109,883	87,592
Income from operations	266,602	142,517	695,884	459,120
Other income (expense)
Interest expense	(3,297)	(11,934)	(14,921)	(35,682)
Debt retirement costs	0	(7,082)	0	(7,082)
Gain from sales of equity securities	0	477	0	16,429
Other (expense) income, net	(287)	1,222	3,137	3,676
Income before income taxes	263,018	125,200	684,100	436,461
Provision for income taxes	92,728	38,236	244,647	146,183
Net income	$ 170,290	$ 86,964	$ 439,453	$ 290,278
Earnings per share:
Basic	$ 2.55	$ 1.30	$ 6.57	$ 4.36
Diluted	$ 2.54	$ 1.30	$ 6.54	$ 4.33
Weighted average shares outstanding:
Basic	66,628,747	66,311,958	66,628,027	66,240,225
Diluted	66,905,554	66,656,760	66,903,379	66,621,520
Dividends per common share	$ 0.2250	$ 0.1875	$ 0.6000	$ 0.3350

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Inventories

9 Months Ended

Sep. 30, 2013

Inventory Disclosure [Abstract]

Inventories

Inventories

Inventories consist of the following:

	September 30, 2013		December 31, 2012
Finished products	$	198,762	$	200,940
Feedstock, additives and chemicals	194,558		143,912
Materials and supplies	58,251		54,446
Inventories	$	451,571	$	399,298

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Goodwill Goodwill

9 Months Ended

Sep. 30, 2013

Goodwill [Abstract]

Goodwill

Goodwill

The changes in the carrying amount of goodwill for the nine months ended September 30, 2013 were as follows:

	Olefins Segment		Vinyls Segment		Total
Balance at December 31, 2012	$	29,990	$	—	$	29,990
Goodwill acquired during the period	—		32,026		32,026
Balance at September 30, 2013	$	29,990	$	32,026	$	62,016

XML

Acquisitions (Assets Acquired and Liabilities Assumed) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended			0 Months Ended			2 Months Ended		2 Months Ended		2 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	May 01, 2013 Pipe and Foundation Group		May 01, 2013 Pipe and Foundation Group Trademarks	Jun. 30, 2013 Pipe and Foundation Group Customer relationships	May 01, 2013 Pipe and Foundation Group Customer relationships	Jun. 30, 2013 Pipe and Foundation Group Developed technology	May 01, 2013 Pipe and Foundation Group Developed technology	Jun. 30, 2013 Pipe and Foundation Group Other intangibles	May 01, 2013 Pipe and Foundation Group Other intangibles
Fair value of consideration transferred:
Cash	$ 178,309	$ 0		$ 178,309
Preliminary allocation of consideration transferred to net assets acquired:
Accounts receivable				17,695	[1]
Inventories				25,948
Property, plant and equipment				31,261
Intangible assets:
Intangible assets						5,200		57,600		18,900		300
Current liabilities				(10,595)
Other liabilities				(26)
Total identifiable net assets				146,283
Goodwill	62,016		29,990	32,026	[2]
Consideration transferred				178,309
Fair value of accounts receivable acquired				17,695
Gross contractual amount of acquired receivables				17,772
Amount of acquired receivables expected to be uncollectible				$ 0
Weighted average life							15 years		15 years		2 years

[1] The fair value of accounts receivable acquired is $17,695, with the gross contractual amount being $17,772. The Company expects $77 to be uncollectible.

[2] The goodwill recognized is primarily attributable to synergies from the Company's vinyls integration strategy expected to arise from the Company's PFG acquisition, as well as intangible assets that do not qualify for separate recognition. The goodwill is expected to be deductible for income tax purposes. The Company has not yet completed the process of assigning the goodwill to its reporting units.

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Fair Value Measurements (Summary of Assets and Liabilities Accounted at Fair Value on Recurring Basis) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	$ 120,602	$ 0
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Hedged portion of firm commitment assets		399
Hedged portion of firm commitment liabilities	(3,208)	(13,032)
Available-for-sale securities	120,602
Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Hedged portion of firm commitment assets		0
Hedged portion of firm commitment liabilities	0	0
Available-for-sale securities	14,998
Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Hedged portion of firm commitment assets		399
Hedged portion of firm commitment liabilities	(3,208)	(13,032)
Available-for-sale securities	105,604
Recurring | Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Risk management assets - Commodity forward contracts	5,749	14,427
Risk management liabilities - Commodity forward contracts	(2,090)	(13,694)
Recurring | Forward Contracts [Member] | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Risk management assets - Commodity forward contracts	1,808	1,395
Risk management liabilities - Commodity forward contracts	(74)	0
Recurring | Forward Contracts [Member] | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Risk management assets - Commodity forward contracts	3,941	13,032
Risk management liabilities - Commodity forward contracts	$ (2,016)	$ (13,694)

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Earnings per Share

9 Months Ended

Sep. 30, 2013

Earnings Per Share [Abstract]

Earnings per Share

Earnings per Share

The Company has unvested shares of restricted stock and restricted stock units outstanding that are considered participating securities and, therefore, computes basic and diluted earnings per share under the two-class method. Basic earnings per share for the periods are based upon the weighted average number of shares of common stock outstanding during the periods. Diluted earnings per share include the effect of certain stock options.

	Three Months Ended September 30,						Nine Months Ended September 30,
	2013			2012			2013			2012
Net income	$	170,290		$	86,964		$	439,453		$	290,278
Less:
Net income attributable to participating securities	(587		)	(452		)	(1,691		)	(1,682		)
Net income attributable to common shareholders	$	169,703		$	86,512		$	437,762		$	288,596

The following table reconciles the denominator for the basic and diluted earnings per share computations shown in the consolidated statements of operations:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2013		2012		2013		2012
Weighted average common shares—basic	66,628,747		66,311,958		66,628,027		66,240,225
Plus incremental shares from:
Assumed exercise of options	276,807		344,802		275,352		381,295
Weighted average common shares—diluted	66,905,554		66,656,760		66,903,379		66,621,520
Earnings per share:
Basic	$	2.55	$	1.30	$	6.57	$	4.36
Diluted	$	2.54	$	1.30	$	6.54	$	4.33

Excluded from the computation of diluted earnings per share are options to purchase 68,662 and 168,362 shares of common stock for the three months ended September 30, 2013 and 2012, respectively, and 57,759 and 293,062 shares of common stock for the nine months ended September 30, 2013 and 2012, respectively. These options were outstanding during the periods reported but were excluded because the effect of including them would have been antidilutive.

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Property, Plant and Equipment (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Property, Plant and Equipment [Abstract]
Property, plant and equipment	$ 1,952,918		$ 1,952,918		$ 1,510,048
Depreciation expense on property, plant and equipment	$ 32,460	$ 30,055	$ 95,995	$ 90,615

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Fair Value Measurements (Summary of Carrying and Fair Values of Long Term Debt) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended					3 Months Ended					3 Months Ended					3 Months Ended					3 Months Ended					3 Months Ended
	Sep. 30, 2013 3.60% Senior Notes Due 2022	Sep. 30, 2013 3.60% Senior Notes Due 2022 Carrying Value	Dec. 31, 2012 3.60% Senior Notes Due 2022 Carrying Value	Sep. 30, 2013 3.60% Senior Notes Due 2022 Fair Value	Dec. 31, 2012 3.60% Senior Notes Due 2022 Fair Value	Sep. 30, 2013 6 1/2% Senior Notes Due 2029	Sep. 30, 2013 6 1/2% Senior Notes Due 2029 Carrying Value	Dec. 31, 2012 6 1/2% Senior Notes Due 2029 Carrying Value	Sep. 30, 2013 6 1/2% Senior Notes Due 2029 Fair Value	Dec. 31, 2012 6 1/2% Senior Notes Due 2029 Fair Value	Sep. 30, 2013 6 3/4% Senior Notes Due 2032	Sep. 30, 2013 6 3/4% Senior Notes Due 2032 Carrying Value	Dec. 31, 2012 6 3/4% Senior Notes Due 2032 Carrying Value	Sep. 30, 2013 6 3/4% Senior Notes Due 2032 Fair Value	Dec. 31, 2012 6 3/4% Senior Notes Due 2032 Fair Value	Sep. 30, 2013 2035 GO Zone 6 1/2% Notes	Sep. 30, 2013 2035 GO Zone 6 1/2% Notes Carrying Value	Dec. 31, 2012 2035 GO Zone 6 1/2% Notes Carrying Value	Sep. 30, 2013 2035 GO Zone 6 1/2% Notes Fair Value	Dec. 31, 2012 2035 GO Zone 6 1/2% Notes Fair Value	Sep. 30, 2013 2035 IKE Zone 6 1/2% Notes	Sep. 30, 2013 2035 IKE Zone 6 1/2% Notes Carrying Value	Dec. 31, 2012 2035 IKE Zone 6 1/2% Notes Carrying Value	Sep. 30, 2013 2035 IKE Zone 6 1/2% Notes Fair Value	Dec. 31, 2012 2035 IKE Zone 6 1/2% Notes Fair Value	Sep. 30, 2013 Loan Related To Tax-Exempt Waste Disposal Revenue Bonds Due 2027	Sep. 30, 2013 Loan Related To Tax-Exempt Waste Disposal Revenue Bonds Due 2027 Carrying Value	Dec. 31, 2012 Loan Related To Tax-Exempt Waste Disposal Revenue Bonds Due 2027 Carrying Value	Sep. 30, 2013 Loan Related To Tax-Exempt Waste Disposal Revenue Bonds Due 2027 Fair Value	Dec. 31, 2012 Loan Related To Tax-Exempt Waste Disposal Revenue Bonds Due 2027 Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Maturity	2022					2029					2032					2035					2035					2027
Stated interest rate	3.60%					6.50%					6.75%					6.50%					6.50%
Senior notes		$ 248,960	$ 248,872	$ 238,228	$ 251,125		$ 100,000	$ 100,000	$ 107,800	$ 119,738		$ 250,000	$ 250,000	$ 267,465	$ 283,168		$ 89,000	$ 89,000	$ 94,209	$ 102,095		$ 65,000	$ 65,000	$ 68,804	$ 74,564
Loans																											$ 10,889	$ 10,889	$ 10,889	$ 10,889

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Segment Information (Tables)

9 Months Ended

Sep. 30, 2013

Segment Reporting [Abstract]

Segment Reporting Information

	Three Months Ended September 30,						Nine Months Ended September 30,
	2013			2012			2013			2012
Net external sales
Olefins
Polyethylene	$	460,105		$	431,614		$	1,294,566		$	1,275,057
Styrene, feedstock and other	219,234			108,171			590,959			669,718
Total Olefins	679,339			539,785			1,885,525			1,944,775
Vinyls
PVC, caustic soda and other	212,041			191,310			612,391			569,316
Building products	112,785			90,080			309,943			255,909
Total Vinyls	324,826			281,390			922,334			825,225
	$	1,004,165		$	821,175		$	2,807,859		$	2,770,000
Intersegment sales
Olefins	$	85,454		$	76,771		$	230,607		$	247,671
Vinyls	403			391			1,111			1,167
	$	85,857		$	77,162		$	231,718		$	248,838
Income (loss) from operations
Olefins	$	237,239		$	124,452		$	585,958		$	409,550
Vinyls	39,554			24,059			136,123			67,724
Corporate and other	(10,191		)	(5,994		)	(26,197		)	(18,154		)
	$	266,602		$	142,517		$	695,884		$	459,120
Depreciation and amortization
Olefins	$	26,515		$	27,070		$	76,415		$	74,903
Vinyls	14,089			11,232			39,507			34,330
Corporate and other	124			122			372			368
	$	40,728		$	38,424		$	116,294		$	109,601
Other income (expense), net
Olefins	$	728		$	806		$	5,889		$	2,764
Vinyls	(742		)	146			(1,687		)	115
Corporate and other	(273		)	270			(1,065		)	797
	$	(287	)	$	1,222		$	3,137		$	3,676
Provision for (benefit from) income taxes
Olefins	$	82,553		$	36,092		$	208,170		$	130,612
Vinyls	10,710			6,556			44,120			18,989
Corporate and other	(535		)	(4,412		)	(7,643		)	(3,418		)
	$	92,728		$	38,236		$	244,647		$	146,183

	Three Months Ended September 30,				Nine Months Ended September 30,
	2013		2012		2013		2012
Capital expenditures
Olefins	$	27,577	$	46,867	$	105,656	$	92,168
Vinyls	172,565		47,001		391,864		139,836
Corporate and other	276		1,027		770		3,459
	$	200,418	$	94,895	$	498,290	$	235,463

Reconciliation Of Total Segment Income From Operations To Consolidated Income Before Income Taxes

A reconciliation of total segment income from operations to consolidated income before income taxes is as follows:

	Three Months Ended September 30,						Nine Months Ended September 30,
	2013			2012			2013			2012
Income from operations	$	266,602		$	142,517		$	695,884		$	459,120
Interest expense	(3,297		)	(11,934		)	(14,921		)	(35,682		)
Debt retirement costs	—			(7,082		)	—			(7,082		)
Gain from sales of equity securities	—			477			—			16,429
Other (expense) income, net	(287		)	1,222			3,137			3,676
Income before income taxes	$	263,018		$	125,200		$	684,100		$	436,461

Total Assets

	September 30, 2013		December 31, 2012
Total assets
Olefins	$	1,560,303	$	1,439,308
Vinyls	1,577,549		1,030,912
Corporate and other	785,597		941,976
	$	3,923,449	$	3,412,196

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Basis of Financial Statements (Policies)

9 Months Ended

Sep. 30, 2013

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Basis of Financial Statements

Basis of Financial Statements

The accompanying unaudited consolidated interim financial statements were prepared in accordance with the rules and regulations of the Securities and Exchange Commission (the "SEC") for interim periods. Accordingly, certain information and footnotes required for complete financial statements under generally accepted accounting principles in the United States ("U.S. GAAP") have not been included. These interim consolidated financial statements should be read in conjunction with the December 31, 2012 financial statements and notes thereto of Westlake Chemical Corporation (the "Company") included in the annual report on Form 10-K for the fiscal year ended December 31, 2012 (the "2012 Form 10-K"), filed with the SEC on February 22, 2013. These financial statements have been prepared in conformity with the accounting principles and practices as disclosed in the notes to the consolidated financial statements of the Company for the fiscal year ended December 31, 2012.

In the opinion of the Company's management, the accompanying unaudited consolidated interim financial statements reflect all adjustments (consisting only of normal recurring adjustments) that are necessary for a fair statement of the Company's financial position as of September 30, 2013, its results of operations for the three and nine months ended September 30, 2013 and 2012 and the changes in its cash position for the nine months ended September 30, 2013 and 2012.

Results of operations and changes in cash position for the interim periods presented are not necessarily indicative of the results that will be realized for the fiscal year ending December 31, 2013 or any other interim period. The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities. Actual results could differ from those estimates.

Recent Accounting Pronouncements

Recent Accounting Pronouncements

Disclosures about Offsetting Assets and Liabilities

In December 2011, the Financial Accounting Standards Board ("FASB") issued an accounting standards update on disclosures for offsetting assets and liabilities. The new accounting guidance requires companies to disclose both gross and net information about (1) instruments and transactions eligible for offset in the statement of financial position, and (2) instruments and transactions subject to an agreement similar to a master netting arrangement. The FASB issued another accounting standards update clarifying the scope of the assets and liabilities offset disclosure requirements in January 2013. The effective date of the disclosure requirements remains unchanged. The Company adopted the new guidance as of January 1, 2013, and the adoption did not have an impact on the Company's consolidated financial position, results of operations or cash flows.

Testing Indefinite-Lived Intangible Assets for Impairment

In July 2012, the FASB issued an accounting standards update to simplify how entities test indefinite-lived intangible assets for impairment and to improve consistency in impairment testing guidance among long-lived asset categories. The new accounting guidance provides an entity with an option to first assess qualitative factors to determine whether it is more likely than not that an indefinite-lived intangible asset is impaired as a basis for determining whether it is necessary to perform the quantitative impairment test under current accounting guidance. If an entity concludes that it is not more likely than not that the indefinite-lived intangible asset is impaired, then the entity is not required to take further action. However, if an entity concludes otherwise, then it is required to determine the fair value of the indefinite-lived intangible asset and perform the quantitative impairment test by comparing the fair value with the carrying amount in accordance with current accounting guidance. Also under this new accounting guidance, an entity has the option to bypass the qualitative assessment for any indefinite-lived intangible asset in any period and proceed directly to performing the quantitative impairment test, but may resume performing the qualitative assessment in any subsequent period. The Company adopted the new indefinite-lived intangible assets test guidance as of January 1, 2013, and the adoption did not have a material impact on the Company's consolidated financial position, results of operations or cash flows.

Reclassifications Out of Accumulated Other Comprehensive Income

In February 2013, the FASB issued an accounting standards update on reporting items reclassified out of accumulated other comprehensive income. The new accounting guidance requires companies to present either parenthetically on the face of the financial statements or in the notes, significant amounts reclassified from each component of accumulated other comprehensive income and the income statement line items affected by the reclassification, with certain exceptions. The Company adopted the new guidance as of January 1, 2013, and the adoption did not have an impact on the Company's consolidated financial position, results of operations or cash flows.

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Guarantor Disclosures

9 Months Ended

Sep. 30, 2013

Guarantees [Abstract]

Guarantor Disclosures

Guarantor Disclosures

The Company's payment obligations under the 3.60% senior notes due 2022 are fully and unconditionally guaranteed by each of its current and future domestic subsidiaries that guarantee other debt of the Company or of another guarantor of the 3.60% senior notes due 2022 in excess of $5,000 (the "Guarantor Subsidiaries"). Each Guarantor Subsidiary is 100% owned by Westlake Chemical Corporation. These guarantees are the joint and several obligations of the Guarantor Subsidiaries. The following unaudited condensed consolidating financial information presents the financial condition, results of operations and cash flows of Westlake Chemical Corporation, the Guarantor Subsidiaries and the remaining subsidiaries that do not guarantee the 3.60% senior notes due 2022 (the "Non-Guarantor Subsidiaries"), together with consolidating adjustments necessary to present the Company's results on a consolidated basis.

Condensed Consolidating Financial Information as of September 30, 2013

	Westlake Chemical Corporation		Guarantor Subsidiaries		Non- Guarantor Subsidiaries		Eliminations			Consolidated
Balance Sheet
Current assets
Cash and cash equivalents	$	560,261	$	4,494	$	26,801	$	—		$	591,556
Marketable securities	125,597		—		—		—			125,597
Accounts receivable, net	5,373		694,473		5,489		(272,310		)	433,025
Inventories	—		435,540		16,031		—			451,571
Prepaid expenses and other    current assets	468		15,931		2,410		—			18,809
Deferred income taxes	431		21,744		118		—			22,293
Total current assets	692,130		1,172,182		50,849		(272,310		)	1,642,851
Property, plant and equipment, net	—		1,945,405		7,513		—			1,952,918
Equity investments	2,635,954		98,823		31,634		(2,700,923		)	65,488
Other assets, net	16,969		251,703		506		(6,986		)	262,192
Total assets	$	3,345,053	$	3,468,113	$	90,502	$	(2,980,219	)	$	3,923,449
Current liabilities
Accounts payable	$	311,357	$	220,106	$	4,322	$	(277,718	)	$	258,067
Accrued liabilities	15,679		151,654		1,878		5,408			174,619
Total current liabilities	327,036		371,760		6,200		(272,310		)	432,686
Long-term debt	752,960		10,889		—		—			763,849
Deferred income taxes	—		416,404		748		(6,986		)	410,166
Other liabilities	—		51,640		51		—			51,691
Stockholders' equity	2,265,057		2,617,420		83,503		(2,700,923		)	2,265,057
Total liabilities and stockholders' equity	$	3,345,053	$	3,468,113	$	90,502	$	(2,980,219	)	$	3,923,449

Condensed Consolidating Financial Information as of December 31, 2012

	Westlake Chemical Corporation		Guarantor Subsidiaries		Non-Guarantor Subsidiaries		Eliminations			Consolidated
Balance Sheet
Current assets
Cash and cash equivalents	$	753,881	$	6,973	$	29,224	$	—		$	790,078
Marketable securities	124,873		—		—		—			124,873
Accounts receivable, net	7,933		1,675,274		2,959		(1,286,007		)	400,159
Inventories	—		385,140		14,158		—			399,298
Prepaid expenses and other    current assets	389		11,386		2,925		—			14,700
Deferred income taxes	431		21,581		293		—			22,305
Total current assets	887,507		2,100,354		49,559		(1,286,007		)	1,751,413
Property, plant and equipment, net	—		1,502,902		7,146		—			1,510,048
Equity investments	3,018,926		65,448		32,923		(3,073,561		)	43,736
Other assets, net	17,033		94,678		1,252		(5,964		)	106,999
Total assets	$	3,923,466	$	3,763,382	$	90,880	$	(4,365,532	)	$	3,412,196
Current liabilities
Accounts payable	$	1,285,530	$	192,443	$	13,969	$	(1,274,892	)	$	217,050
Accrued liabilities	12,808		178,915		852		(11,115		)	181,460
Total current liabilities	1,298,338		371,358		14,821		(1,286,007		)	398,510
Long-term debt	752,872		10,889		—		—			763,761
Deferred income taxes	—		331,320		934		(5,964		)	326,290
Other liabilities	—		51,312		67		—			51,379
Stockholders' equity	1,872,256		2,998,503		75,058		(3,073,561		)	1,872,256
Total liabilities and stockholders' equity	$	3,923,466	$	3,763,382	$	90,880	$	(4,365,532	)	$	3,412,196

Condensed Consolidating Financial Information for the Three Months Ended September 30, 2013

	Westlake Chemical Corporation			Guarantor Subsidiaries			Non- Guarantor Subsidiaries			Eliminations			Consolidated
Statement of Operations
Net sales	$	—		$	992,413		$	13,337		$	(1,585	)	$	1,004,165
Cost of sales	—			689,388			11,891			(1,585		)	699,694
Gross profit	—			303,025			1,446			—			304,471
Selling, general and administrative    expenses	514			35,714			1,641			—			37,869
(Loss) income from operations	(514		)	267,311			(195		)	—			266,602
Interest expense	(3,292		)	(5		)	—			—			(3,297		)
Other income (expense), net	3,585			(3,821		)	(51		)	—			(287		)
(Loss) income before income taxes	(221		)	263,485			(246		)	—			263,018
(Benefit from) provision for income taxes	(70		)	92,849			(51		)	—			92,728
Equity in net income of subsidiaries	170,441			—			—			(170,441		)	—
Net income (loss)	$	170,290		$	170,636		$	(195	)	$	(170,441	)	$	170,290
Comprehensive income	$	171,095		$	170,764		$	351		$	(171,115	)	$	171,095

Condensed Consolidating Financial Information for the Three Months Ended September 30, 2012

	Westlake Chemical Corporation			Guarantor Subsidiaries			Non- Guarantor Subsidiaries			Eliminations			Consolidated
Statement of Operations
Net sales	$	—		$	809,164		$	13,876		$	(1,865	)	$	821,175
Cost of sales	—			638,892			11,969			(1,865		)	648,996
Gross profit	—			170,272			1,907			—			172,179
Selling, general and administrative    expenses	498			27,601			1,563			—			29,662
(Loss) income from operations	(498		)	142,671			344			—			142,517
Interest expense	(11,919		)	(15		)	—			—			(11,934		)
Debt retirement costs	(7,082		)	—			—			—			(7,082		)
Gain from sales of equity securities	—			477			—			—			477
Other income (expense), net	4,556			(2,744		)	(590		)	—			1,222
(Loss) income before income taxes	(14,943		)	140,389			(246		)	—			125,200
(Benefit from) provision for income taxes	(4,498		)	42,596			138			—			38,236
Equity in net income of subsidiaries	97,409			—			—			(97,409		)	—
Net income (loss)	$	86,964		$	97,793		$	(384	)	$	(97,409	)	$	86,964
Comprehensive income	$	88,666		$	98,109		$	481		$	(98,590	)	$	88,666

Condensed Consolidating Financial Information for the Nine Months Ended September 30, 2013

	Westlake Chemical Corporation			Guarantor Subsidiaries			Non- Guarantor Subsidiaries			Eliminations			Consolidated
Statement of Operations
Net sales	$	—		$	2,777,280		$	37,561		$	(6,982	)	$	2,807,859
Cost of sales	—			1,976,131			32,943			(6,982		)	2,002,092
Gross profit	—			801,149			4,618			—			805,767
Selling, general and administrative    expenses	1,576			103,478			4,829			—			109,883
(Loss) income from operations	(1,576		)	697,671			(211		)	—			695,884
Interest expense	(14,882		)	(39		)	—			—			(14,921		)
Other income (expense), net	7,490			(2,473		)	(1,880		)	—			3,137
(Loss) income before income taxes	(8,968		)	695,159			(2,091		)	—			684,100
(Benefit from) provision for income taxes	(3,202		)	248,301			(452		)	—			244,647
Equity in net income of subsidiaries	445,219			—			—			(445,219		)	—
Net income (loss)	$	439,453		$	446,858		$	(1,639	)	$	(445,219	)	$	439,453
Comprehensive income (loss)	$	439,372		$	447,490		$	(2,483	)	$	(445,007	)	$	439,372

Condensed Consolidating Financial Information for the Nine Months Ended September 30, 2012

	Westlake Chemical Corporation			Guarantor Subsidiaries			Non- Guarantor Subsidiaries			Eliminations			Consolidated
Statement of Operations
Net sales	$	—		$	2,738,180		$	37,154		$	(5,334	)	$	2,770,000
Cost of sales	—			2,197,300			31,322			(5,334		)	2,223,288
Gross profit	—			540,880			5,832			—			546,712
Selling, general and administrative    expenses	1,500			81,288			4,804			—			87,592
(Loss) income from operations	(1,500		)	459,592			1,028			—			459,120
Interest expense	(35,652		)	(30		)	—			—			(35,682		)
Debt retirement costs	(7,082		)	—			—			—			(7,082		)
Gain from sales of equity securities	1			16,428			—			—			16,429
Other income (expense), net	12,044			(5,724		)	(2,644		)	—			3,676
(Loss) income before income taxes	(32,189		)	470,266			(1,616		)	—			436,461
(Benefit from) provision for income taxes	(11,105		)	158,228			(940		)	—			146,183
Equity in net income of subsidiaries	311,362			—			—			(311,362		)	—
Net income (loss)	$	290,278		$	312,038		$	(676	)	$	(311,362	)	$	290,278
Comprehensive income	$	291,185		$	312,017		$	252		$	(312,269	)	$	291,185

Condensed Consolidating Financial Information for the Nine Months Ended September 30, 2013

	Westlake Chemical Corporation			Guarantor Subsidiaries			Non- Guarantor Subsidiaries			Eliminations			Consolidated
Statement of Cash Flows
Cash flows from operating activities
Net income (loss)	$	439,453		$	446,858		$	(1,639	)	$	(445,219	)	$	439,453
Adjustments to reconcile net income    (loss) to net cash (used for) provided    by operating activities
Depreciation and amortization	1,094			114,432			1,861			—			117,387
Deferred income taxes	(1,102		)	84,532			13			—			83,443
Net changes in working capital    and other	(458,336		)	(87,330		)	7,664			445,219			(92,783		)
Net cash (used for) provided by    operating activities	(18,891		)	558,492			7,899			—			547,500
Cash flows from investing activities
Acquisition of business	—			(178,309		)	—			—			(178,309		)
Additions to equity investments	—			(23,338		)	—			—			(23,338		)
Additions to property, plant and    equipment	—			(496,027		)	(2,263		)	—			(498,290		)
Construction of assets pending    sale-leaseback	—			(136		)	—			—			(136		)
Proceeds from disposition of assets	—			6			72			—			78
Proceeds from repayment of loan    to affiliate	—			—			167			—			167
Proceeds from sales and maturities of    securities	239,764			—			—			—			239,764
Purchase of securities	(232,286		)	—			—			—			(232,286		)
Settlements of derivative instruments	—			(2,297		)	—			—			(2,297		)
Net cash provided by (used for)    investing activities	7,478			(700,101		)	(2,024		)	—			(694,647		)
Cash flows from financing activities
Intercompany financing	(130,832		)	139,130			(8,298		)	—			—
Dividends paid	(40,204		)	—			—			—			(40,204		)
Proceeds from exercise of stock options	3,182			—			—			—			3,182
Repurchase of common stock for treasury	(19,409		)	—			—			—			(19,409		)
Windfall tax benefits from share-based    payment arrangements	5,056			—			—			—			5,056
Net cash (used for) provided by    financing activities	(182,207		)	139,130			(8,298		)	—			(51,375		)
Net decrease in cash and cash equivalents	(193,620		)	(2,479		)	(2,423		)	—			(198,522		)
Cash and cash equivalents at beginning    of period	753,881			6,973			29,224			—			790,078
Cash and cash equivalents at end of period	$	560,261		$	4,494		$	26,801		$	—		$	591,556

Condensed Consolidating Financial Information for the Nine Months Ended September 30, 2012

	Westlake Chemical Corporation			Guarantor Subsidiaries			Non- Guarantor Subsidiaries			Eliminations			Consolidated
Statement of Cash Flows
Cash flows from operating activities
Net income (loss)	$	290,278		$	312,038		$	(676	)	$	(311,362	)	$	290,278
Adjustments to reconcile net income    (loss) to net cash (used for) provided    by operating activities
Depreciation and amortization	1,149			107,191			2,410			—			110,750
Deferred income taxes	(176		)	3,932			629			—			4,385
Net changes in working capital    and other	(317,955		)	95,909			(1,898		)	311,362			87,418
Net cash (used for) provided by    operating activities	(26,704		)	519,070			465			—			492,831
Cash flows from investing activities
Additions to property, plant and    equipment	—			(234,713		)	(750		)	—			(235,463		)
Construction of assets pending    sale-leaseback	—			(5,484		)	—			—			(5,484		)
Proceeds from disposition of assets	—			414			21			—			435
Proceeds from repayment of loan    to affiliate	—			—			763			—			763
Proceeds from sales of equity securities	3			47,652			—			—			47,655
Purchase of securities	—			(2,961		)	—			—			(2,961		)
Settlements of derivative instruments	—			471			—			—			471
Net cash provided by (used for)    investing activities	3			(194,621		)	34			—			(194,584		)
Cash flows from financing activities
Intercompany financing	317,185			(321,273		)	4,088			—			—
Capitalized debt issuance costs	(2,221		)	—			—			—			(2,221		)
Dividends paid	(22,345		)	—			—			—			(22,345		)
Proceeds from borrowings	248,818			—			—			—			248,818
Proceeds from exercise of stock options	6,627			—			—			—			6,627
Repayment of borrowings	(250,000		)	—			—			—			(250,000		)
Repurchase of common stock for treasury	(10,784		)	—			—			—			(10,784		)
Utilization of restricted cash	96,433			—			—			—			96,433
Windfall tax benefits from share-based    payment arrangements	7,792			—			—			—			7,792
Net cash provided by (used for)    financing activities	391,505			(321,273		)	4,088			—			74,320
Net increase in cash and cash equivalents	364,804			3,176			4,587			—			372,567
Cash and cash equivalents at beginning    of period	803,320			2,517			20,064			—			825,901
Cash and cash equivalents at end of period	$	1,168,124		$	5,693		$	24,651		$	—		$	1,198,468

XML

Accounts Receivable (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Accounts Receivable, Net [Abstract]
Trade customers	$ 404,678	$ 388,949
Affiliates	333	258
Allowance for doubtful accounts	(9,832)	(11,172)
Receivables from trade customers and affiliates, net	395,179	378,035
Federal and state taxes	20,421	4,011
Other	17,425	18,113
Accounts receivable, net	$ 433,025	$ 400,159

XML

Earnings per Share (Tables)

9 Months Ended

Sep. 30, 2013

Earnings Per Share [Abstract]

Schedule Of Net Income Attributable To Common Stockholders

	Three Months Ended September 30,						Nine Months Ended September 30,
	2013			2012			2013			2012
Net income	$	170,290		$	86,964		$	439,453		$	290,278
Less:
Net income attributable to participating securities	(587		)	(452		)	(1,691		)	(1,682		)
Net income attributable to common shareholders	$	169,703		$	86,512		$	437,762		$	288,596

Reconciliation Of Denominator For Basic And Diluted Earnings Per Share

The following table reconciles the denominator for the basic and diluted earnings per share computations shown in the consolidated statements of operations:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2013		2012		2013		2012
Weighted average common shares—basic	66,628,747		66,311,958		66,628,027		66,240,225
Plus incremental shares from:
Assumed exercise of options	276,807		344,802		275,352		381,295
Weighted average common shares—diluted	66,905,554		66,656,760		66,903,379		66,621,520
Earnings per share:
Basic	$	2.55	$	1.30	$	6.57	$	4.36
Diluted	$	2.54	$	1.30	$	6.54	$	4.33

XML

Guarantor Disclosures (Tables)

9 Months Ended

Sep. 30, 2013

Guarantees [Abstract]

Condensed Consolidating Financial Information Balance Sheet

Condensed Consolidating Financial Information as of September 30, 2013

	Westlake Chemical Corporation		Guarantor Subsidiaries		Non- Guarantor Subsidiaries		Eliminations			Consolidated
Balance Sheet
Current assets
Cash and cash equivalents	$	560,261	$	4,494	$	26,801	$	—		$	591,556
Marketable securities	125,597		—		—		—			125,597
Accounts receivable, net	5,373		694,473		5,489		(272,310		)	433,025
Inventories	—		435,540		16,031		—			451,571
Prepaid expenses and other    current assets	468		15,931		2,410		—			18,809
Deferred income taxes	431		21,744		118		—			22,293
Total current assets	692,130		1,172,182		50,849		(272,310		)	1,642,851
Property, plant and equipment, net	—		1,945,405		7,513		—			1,952,918
Equity investments	2,635,954		98,823		31,634		(2,700,923		)	65,488
Other assets, net	16,969		251,703		506		(6,986		)	262,192
Total assets	$	3,345,053	$	3,468,113	$	90,502	$	(2,980,219	)	$	3,923,449
Current liabilities
Accounts payable	$	311,357	$	220,106	$	4,322	$	(277,718	)	$	258,067
Accrued liabilities	15,679		151,654		1,878		5,408			174,619
Total current liabilities	327,036		371,760		6,200		(272,310		)	432,686
Long-term debt	752,960		10,889		—		—			763,849
Deferred income taxes	—		416,404		748		(6,986		)	410,166
Other liabilities	—		51,640		51		—			51,691
Stockholders' equity	2,265,057		2,617,420		83,503		(2,700,923		)	2,265,057
Total liabilities and stockholders' equity	$	3,345,053	$	3,468,113	$	90,502	$	(2,980,219	)	$	3,923,449

Condensed Consolidating Financial Information as of December 31, 2012

	Westlake Chemical Corporation		Guarantor Subsidiaries		Non-Guarantor Subsidiaries		Eliminations			Consolidated
Balance Sheet
Current assets
Cash and cash equivalents	$	753,881	$	6,973	$	29,224	$	—		$	790,078
Marketable securities	124,873		—		—		—			124,873
Accounts receivable, net	7,933		1,675,274		2,959		(1,286,007		)	400,159
Inventories	—		385,140		14,158		—			399,298
Prepaid expenses and other    current assets	389		11,386		2,925		—			14,700
Deferred income taxes	431		21,581		293		—			22,305
Total current assets	887,507		2,100,354		49,559		(1,286,007		)	1,751,413
Property, plant and equipment, net	—		1,502,902		7,146		—			1,510,048
Equity investments	3,018,926		65,448		32,923		(3,073,561		)	43,736
Other assets, net	17,033		94,678		1,252		(5,964		)	106,999
Total assets	$	3,923,466	$	3,763,382	$	90,880	$	(4,365,532	)	$	3,412,196
Current liabilities
Accounts payable	$	1,285,530	$	192,443	$	13,969	$	(1,274,892	)	$	217,050
Accrued liabilities	12,808		178,915		852		(11,115		)	181,460
Total current liabilities	1,298,338		371,358		14,821		(1,286,007		)	398,510
Long-term debt	752,872		10,889		—		—			763,761
Deferred income taxes	—		331,320		934		(5,964		)	326,290
Other liabilities	—		51,312		67		—			51,379
Stockholders' equity	1,872,256		2,998,503		75,058		(3,073,561		)	1,872,256
Total liabilities and stockholders' equity	$	3,923,466	$	3,763,382	$	90,880	$	(4,365,532	)	$	3,412,196

Condensed Consolidating Financial Information Statement Of Operations

Condensed Consolidating Financial Information for the Three Months Ended September 30, 2013

	Westlake Chemical Corporation			Guarantor Subsidiaries			Non- Guarantor Subsidiaries			Eliminations			Consolidated
Statement of Operations
Net sales	$	—		$	992,413		$	13,337		$	(1,585	)	$	1,004,165
Cost of sales	—			689,388			11,891			(1,585		)	699,694
Gross profit	—			303,025			1,446			—			304,471
Selling, general and administrative    expenses	514			35,714			1,641			—			37,869
(Loss) income from operations	(514		)	267,311			(195		)	—			266,602
Interest expense	(3,292		)	(5		)	—			—			(3,297		)
Other income (expense), net	3,585			(3,821		)	(51		)	—			(287		)
(Loss) income before income taxes	(221		)	263,485			(246		)	—			263,018
(Benefit from) provision for income taxes	(70		)	92,849			(51		)	—			92,728
Equity in net income of subsidiaries	170,441			—			—			(170,441		)	—
Net income (loss)	$	170,290		$	170,636		$	(195	)	$	(170,441	)	$	170,290
Comprehensive income	$	171,095		$	170,764		$	351		$	(171,115	)	$	171,095

Condensed Consolidating Financial Information for the Three Months Ended September 30, 2012

	Westlake Chemical Corporation			Guarantor Subsidiaries			Non- Guarantor Subsidiaries			Eliminations			Consolidated
Statement of Operations
Net sales	$	—		$	809,164		$	13,876		$	(1,865	)	$	821,175
Cost of sales	—			638,892			11,969			(1,865		)	648,996
Gross profit	—			170,272			1,907			—			172,179
Selling, general and administrative    expenses	498			27,601			1,563			—			29,662
(Loss) income from operations	(498		)	142,671			344			—			142,517
Interest expense	(11,919		)	(15		)	—			—			(11,934		)
Debt retirement costs	(7,082		)	—			—			—			(7,082		)
Gain from sales of equity securities	—			477			—			—			477
Other income (expense), net	4,556			(2,744		)	(590		)	—			1,222
(Loss) income before income taxes	(14,943		)	140,389			(246		)	—			125,200
(Benefit from) provision for income taxes	(4,498		)	42,596			138			—			38,236
Equity in net income of subsidiaries	97,409			—			—			(97,409		)	—
Net income (loss)	$	86,964		$	97,793		$	(384	)	$	(97,409	)	$	86,964
Comprehensive income	$	88,666		$	98,109		$	481		$	(98,590	)	$	88,666

Condensed Consolidating Financial Information for the Nine Months Ended September 30, 2013

	Westlake Chemical Corporation			Guarantor Subsidiaries			Non- Guarantor Subsidiaries			Eliminations			Consolidated
Statement of Operations
Net sales	$	—		$	2,777,280		$	37,561		$	(6,982	)	$	2,807,859
Cost of sales	—			1,976,131			32,943			(6,982		)	2,002,092
Gross profit	—			801,149			4,618			—			805,767
Selling, general and administrative    expenses	1,576			103,478			4,829			—			109,883
(Loss) income from operations	(1,576		)	697,671			(211		)	—			695,884
Interest expense	(14,882		)	(39		)	—			—			(14,921		)
Other income (expense), net	7,490			(2,473		)	(1,880		)	—			3,137
(Loss) income before income taxes	(8,968		)	695,159			(2,091		)	—			684,100
(Benefit from) provision for income taxes	(3,202		)	248,301			(452		)	—			244,647
Equity in net income of subsidiaries	445,219			—			—			(445,219		)	—
Net income (loss)	$	439,453		$	446,858		$	(1,639	)	$	(445,219	)	$	439,453
Comprehensive income (loss)	$	439,372		$	447,490		$	(2,483	)	$	(445,007	)	$	439,372

Condensed Consolidating Financial Information for the Nine Months Ended September 30, 2012

	Westlake Chemical Corporation			Guarantor Subsidiaries			Non- Guarantor Subsidiaries			Eliminations			Consolidated
Statement of Operations
Net sales	$	—		$	2,738,180		$	37,154		$	(5,334	)	$	2,770,000
Cost of sales	—			2,197,300			31,322			(5,334		)	2,223,288
Gross profit	—			540,880			5,832			—			546,712
Selling, general and administrative    expenses	1,500			81,288			4,804			—			87,592
(Loss) income from operations	(1,500		)	459,592			1,028			—			459,120
Interest expense	(35,652		)	(30		)	—			—			(35,682		)
Debt retirement costs	(7,082		)	—			—			—			(7,082		)
Gain from sales of equity securities	1			16,428			—			—			16,429
Other income (expense), net	12,044			(5,724		)	(2,644		)	—			3,676
(Loss) income before income taxes	(32,189		)	470,266			(1,616		)	—			436,461
(Benefit from) provision for income taxes	(11,105		)	158,228			(940		)	—			146,183
Equity in net income of subsidiaries	311,362			—			—			(311,362		)	—
Net income (loss)	$	290,278		$	312,038		$	(676	)	$	(311,362	)	$	290,278
Comprehensive income	$	291,185		$	312,017		$	252		$	(312,269	)	$	291,185

Condensed Consolidating Financial Information Statement Of Cash Flows

Condensed Consolidating Financial Information for the Nine Months Ended September 30, 2013

	Westlake Chemical Corporation			Guarantor Subsidiaries			Non- Guarantor Subsidiaries			Eliminations			Consolidated
Statement of Cash Flows
Cash flows from operating activities
Net income (loss)	$	439,453		$	446,858		$	(1,639	)	$	(445,219	)	$	439,453
Adjustments to reconcile net income    (loss) to net cash (used for) provided    by operating activities
Depreciation and amortization	1,094			114,432			1,861			—			117,387
Deferred income taxes	(1,102		)	84,532			13			—			83,443
Net changes in working capital    and other	(458,336		)	(87,330		)	7,664			445,219			(92,783		)
Net cash (used for) provided by    operating activities	(18,891		)	558,492			7,899			—			547,500
Cash flows from investing activities
Acquisition of business	—			(178,309		)	—			—			(178,309		)
Additions to equity investments	—			(23,338		)	—			—			(23,338		)
Additions to property, plant and    equipment	—			(496,027		)	(2,263		)	—			(498,290		)
Construction of assets pending    sale-leaseback	—			(136		)	—			—			(136		)
Proceeds from disposition of assets	—			6			72			—			78
Proceeds from repayment of loan    to affiliate	—			—			167			—			167
Proceeds from sales and maturities of    securities	239,764			—			—			—			239,764
Purchase of securities	(232,286		)	—			—			—			(232,286		)
Settlements of derivative instruments	—			(2,297		)	—			—			(2,297		)
Net cash provided by (used for)    investing activities	7,478			(700,101		)	(2,024		)	—			(694,647		)
Cash flows from financing activities
Intercompany financing	(130,832		)	139,130			(8,298		)	—			—
Dividends paid	(40,204		)	—			—			—			(40,204		)
Proceeds from exercise of stock options	3,182			—			—			—			3,182
Repurchase of common stock for treasury	(19,409		)	—			—			—			(19,409		)
Windfall tax benefits from share-based    payment arrangements	5,056			—			—			—			5,056
Net cash (used for) provided by    financing activities	(182,207		)	139,130			(8,298		)	—			(51,375		)
Net decrease in cash and cash equivalents	(193,620		)	(2,479		)	(2,423		)	—			(198,522		)
Cash and cash equivalents at beginning    of period	753,881			6,973			29,224			—			790,078
Cash and cash equivalents at end of period	$	560,261		$	4,494		$	26,801		$	—		$	591,556

Condensed Consolidating Financial Information for the Nine Months Ended September 30, 2012

	Westlake Chemical Corporation			Guarantor Subsidiaries			Non- Guarantor Subsidiaries			Eliminations			Consolidated
Statement of Cash Flows
Cash flows from operating activities
Net income (loss)	$	290,278		$	312,038		$	(676	)	$	(311,362	)	$	290,278
Adjustments to reconcile net income    (loss) to net cash (used for) provided    by operating activities
Depreciation and amortization	1,149			107,191			2,410			—			110,750
Deferred income taxes	(176		)	3,932			629			—			4,385
Net changes in working capital    and other	(317,955		)	95,909			(1,898		)	311,362			87,418
Net cash (used for) provided by    operating activities	(26,704		)	519,070			465			—			492,831
Cash flows from investing activities
Additions to property, plant and    equipment	—			(234,713		)	(750		)	—			(235,463		)
Construction of assets pending    sale-leaseback	—			(5,484		)	—			—			(5,484		)
Proceeds from disposition of assets	—			414			21			—			435
Proceeds from repayment of loan    to affiliate	—			—			763			—			763
Proceeds from sales of equity securities	3			47,652			—			—			47,655
Purchase of securities	—			(2,961		)	—			—			(2,961		)
Settlements of derivative instruments	—			471			—			—			471
Net cash provided by (used for)    investing activities	3			(194,621		)	34			—			(194,584		)
Cash flows from financing activities
Intercompany financing	317,185			(321,273		)	4,088			—			—
Capitalized debt issuance costs	(2,221		)	—			—			—			(2,221		)
Dividends paid	(22,345		)	—			—			—			(22,345		)
Proceeds from borrowings	248,818			—			—			—			248,818
Proceeds from exercise of stock options	6,627			—			—			—			6,627
Repayment of borrowings	(250,000		)	—			—			—			(250,000		)
Repurchase of common stock for treasury	(10,784		)	—			—			—			(10,784		)
Utilization of restricted cash	96,433			—			—			—			96,433
Windfall tax benefits from share-based    payment arrangements	7,792			—			—			—			7,792
Net cash provided by (used for)    financing activities	391,505			(321,273		)	4,088			—			74,320
Net increase in cash and cash equivalents	364,804			3,176			4,587			—			372,567
Cash and cash equivalents at beginning    of period	803,320			2,517			20,064			—			825,901
Cash and cash equivalents at end of period	$	1,168,124		$	5,693		$	24,651		$	—		$	1,198,468

XML

Other Assets (Additional Information) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Other Assets [Abstract]
Amortization expense on intangible assets, included in other assets	$ 8,634	$ 8,717	$ 21,392	$ 20,135

XML

Long-Term Debt (Tables)

9 Months Ended

Sep. 30, 2013

Debt Disclosure [Abstract]

Schedule Of Long-Term Debt

Long-term debt consists of the following:

	September 30, 2013		December 31, 2012
3.60% senior notes due 2022	$	248,960	$	248,872
6 ½% senior notes due 2029	100,000		100,000
6 ¾% senior notes due 2032	250,000		250,000
6 ½% senior notes due 2035 (the "6 ½% GO Zone Senior Notes Due 2035")	89,000		89,000
6 ½% senior notes due 2035 (the "6 ½% IKE Zone Senior Notes Due 2035")	65,000		65,000
Loan related to tax-exempt waste disposal revenue bonds due 2027	10,889		10,889
Long-term debt, net	$	763,849	$	763,761

XML

Accumulated Other Comprehensive Income Changes in AOCI (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), beginning balance	$ (10,840)
Other comprehensive loss before reclassifications	(1,314)
Amounts reclassified from accumulated other comprehensive loss	1,233
Net other comprehensive income (loss) for the period	(81)
Accumulated other comprehensive income (loss), ending balance	(10,921)
Benefits Liability, Net of Tax
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), beginning balance	(16,351)
Other comprehensive loss before reclassifications	(601)
Amounts reclassified from accumulated other comprehensive loss	1,233
Net other comprehensive income (loss) for the period	632
Accumulated other comprehensive income (loss), ending balance	(15,719)
Cumulative Foreign Currency Exchange
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), beginning balance	5,511
Other comprehensive loss before reclassifications	(844)
Amounts reclassified from accumulated other comprehensive loss	0
Net other comprehensive income (loss) for the period	(844)
Accumulated other comprehensive income (loss), ending balance	4,667
Net Unrealized Holding Gains on Investmetnts, Net of Tax
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), beginning balance	0
Other comprehensive loss before reclassifications	131
Amounts reclassified from accumulated other comprehensive loss	0
Net other comprehensive income (loss) for the period	131
Accumulated other comprehensive income (loss), ending balance	$ 131

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Segment Information (Reconciliation of Total Segment Income from Operations to Consolidated Income before Income Taxes) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Segment Reporting [Abstract]
Income from operations	$ 266,602	$ 142,517	$ 695,884	$ 459,120
Interest expense	(3,297)	(11,934)	(14,921)	(35,682)
Debt retirement costs	0	(7,082)	0	(7,082)
Gain from sales of equity securities	0	477	0	16,429
Other (expense) income, net	(287)	1,222	3,137	3,676
Income before income taxes	$ 263,018	$ 125,200	$ 684,100	$ 436,461

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Pension and Post-Retirement Benefit Costs (Additional Information) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Defined Benefit Plan Disclosure [Line Items]
Document Fiscal Year Focus	2013
Salaried Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Employer contribution	$ 776	$ 2,283
Expected additional contributions	388
Wage Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Employer contribution	640	1,542
Expected additional contributions	$ 290

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Current Marketable Securities Available-for-sale Securities (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Change in Net Unrealized Holding Gain (Loss), Net of Tax	$ 131
Available-for-sale Securities, Amortized Cost Basis	120,397
AvailableForSaleDebtSecuritiesGrossUnrealizedGainAccumulatedInInvestments	241
Available ForSaleDebtSecuritiesGrossUnrealizedLossAccumulatedInInvestments	(36)
Available-for-sale securities	120,602	0
Available-for-sale Securities, Income Tax Expense on Change in Unrealized Holding Gain (Loss)	74
Corporate bonds
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	11,888
AvailableForSaleDebtSecuritiesGrossUnrealizedGainAccumulatedInInvestments	191
Available ForSaleDebtSecuritiesGrossUnrealizedLossAccumulatedInInvestments	(21)
Available-for-sale securities	12,058
U.S. government debt
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	26,400
AvailableForSaleDebtSecuritiesGrossUnrealizedGainAccumulatedInInvestments	23
Available ForSaleDebtSecuritiesGrossUnrealizedLossAccumulatedInInvestments	(6)
Available-for-sale securities	26,417
Asset-backed securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	82,109
AvailableForSaleDebtSecuritiesGrossUnrealizedGainAccumulatedInInvestments	27
Available ForSaleDebtSecuritiesGrossUnrealizedLossAccumulatedInInvestments	(9)
Available-for-sale securities	$ 82,127

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Commitments and Contingencies (Additional Information) (Detail) (USD $) In Thousands, unless otherwise specified	0 Months Ended	1 Months Ended		12 Months Ended
	Mar. 17, 2010	Dec. 31, 2007	Dec. 31, 2007 Polyone	Dec. 31, 2012 Polyone
Commitments and Contingencies Disclosure [Line Items]
Minimum number of years between arbitrations		5 years
Reimbursement of remediation costs sought by PolyOne	$ 1,400
Percentage of costs related to environmental issues to be paid by PolyOne			100.00%
Costs incurred environmental remediation services				$ 2,687

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Subsequent Events

9 Months Ended

Sep. 30, 2013

Subsequent Events [Abstract]

Subsequent Events

Subsequent Events

Subsequent events were evaluated through the date on which the financial statements were issued.

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Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities
Net income	$ 439,453	$ 290,278
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	116,294	109,601
Provision for (recovery of) doubtful accounts	3,600	(536)
Amortization of debt issuance costs	1,093	1,149
Stock-based compensation expense	4,804	4,640
Loss from disposition of fixed assets	4,679	1,945
Gain from sales of equity securities	0	(16,429)
Write off of Deferred Debt Issuance Cost	0	1,277
Deferred income taxes	83,443	4,385
Windfall tax benefits from share-based payment arrangements	(5,056)	(7,792)
Equity in (income) loss of joint ventures	1,586	2,567
Changes in operating assets and liabilities
Accounts receivable	(18,874)	13,732
Inventories	(26,325)	119,240
Prepaid expenses and other current assets	(5,038)	(1,977)
Accounts payable	19,518	(35,651)
Accrued liabilities	(15,755)	20,077
Other, net	(55,922)	(13,675)
Net cash provided by operating activities	547,500	492,831
Cash flows from investing activities
Acquisition of business	(178,309)	0
Additions to equity investments	(23,338)	0
Additions to property, plant and equipment	(498,290)	(235,463)
Construction of assets pending sale-leaseback	(136)	(5,484)
Proceeds from disposition of assets	78	435
Proceeds from repayment of loan to affiliate	167	763
Proceeds from sale and maturities of securities	239,764	47,655
Purchase of securities and other investments	(232,286)	(2,961)
Settlements of derivative instruments	(2,297)	471
Net cash used for investing activities	(694,647)	(194,584)
Cash flows from financing activities
Capitalized debt issuance costs	0	(2,221)
Dividends paid	(40,204)	(22,345)
Proceeds from Issuance of Long-term Debt	0	248,818
Proceeds from exercise of stock options	3,182	6,627
Repayments of Long-term Debt	0	250,000
Repurchase of common stock for treasury	(19,409)	(10,784)
Utilization of restricted cash	0	96,433
Windfall tax benefits from share-based payment arrangements	5,056	7,792
Net cash provided by financing activities	(51,375)	74,320
Net increase in cash and cash equivalents	(198,522)	372,567
Cash and cash equivalents at beginning of period	790,078	825,901
Cash and cash equivalents at end of period	$ 591,556	$ 1,198,468

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Current Marketable Securities

9 Months Ended

Sep. 30, 2013

Investments, Debt and Equity Securities [Abstract]

Current Marketable Securities

Current Marketable Securities

The Company’s investments in current marketable securities were classified as follows:

	September 30, 2013		December 31, 2012
Available-for-sale securities	$	120,602	$	—
Held-to-maturity securities	4,995		124,873
Marketable securities	$	125,597	$	124,873

Available-for-Sale Securities

The cost, gross unrealized gains, gross unrealized losses and fair value of the Company’s available-for-sale securities were as follows:

	September 30, 2013
	Cost		Gross Unrealized Gains		Gross Unrealized Losses (1)			Fair Value
Debt securities
Corporate bonds	$	11,888	$	191	$	(21	)	$	12,058
U.S. government debt (2)	26,400		23		(6		)	26,417
Asset-backed securities	82,109		27		(9		)	82,127
Total available-for-sale securities	$	120,397	$	241	$	(36	)	$	120,602

_____________

(1) All unrealized loss positions were held at a loss for less than 12 months.

(2) U.S. Treasury obligations, U.S. government agency obligations and U.S government agency mortgage-backed securities.

As of September 30, 2013, net unrealized gains on the Company's available-for-sale securities of $131, net of income tax expense of $74, were recorded in accumulated other comprehensive income. See Note 10 for the fair value hierarchy of the Company’s available-for-sale securities.

As of September 30, 2013, the corporate bond securities held by the Company had maturities between one to five years, U.S. government debt securities, excluding U.S. government agency mortgage-backed securities, had maturities of less than one year, U.S. government agency mortgage-backed securities had maturities between four to 26 years and asset-backed securities had maturities between two to five years.

Held-to-Maturity Securities

The Company owned held-to-maturity securities of $4,995 and $124,873 at September 30, 2013 and December 31, 2012, respectively, consisting of short-term corporate debt securities with maturities exceeding three months at the date of acquisition. These debt securities are carried at amortized cost, which approximates their fair value.

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Property, Plant and Equipment

9 Months Ended

Sep. 30, 2013

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment

Property, Plant and Equipment

As of September 30, 2013, the Company had property, plant and equipment, net totaling $1,952,918. The Company assesses these assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable, including when negative conditions such as significant current or projected operating losses exist. Other factors considered by the Company when determining if an impairment assessment is necessary include, but are not limited to, significant changes or projected changes in supply and demand fundamentals (which would have a negative impact on operating rates or margins), new technological developments, new competitors with significant raw material or other cost advantages, adverse changes associated with the U.S. and world economies and uncertainties associated with governmental actions. Long-lived assets assessed for impairment are grouped at the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets and liabilities.

Depreciation expense on property, plant and equipment of $32,460 and $30,055 is included in cost of sales in the consolidated statements of operations for the three months ended September 30, 2013 and 2012, respectively. Depreciation expense on property, plant and equipment of $95,995 and $90,615 is included in cost of sales in the consolidated statements of operations for the nine months ended September 30, 2013 and 2012, respectively.

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Segment Information (Total Assets) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 3,923,449	$ 3,412,196
Olefins
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	1,560,303	1,439,308
Vinyls
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	1,577,549	1,030,912
Corporate and Other
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 785,597	$ 941,976

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Accounts Receivable

9 Months Ended

Sep. 30, 2013

Accounts Receivable, Net [Abstract]

Accounts Receivable

Accounts Receivable

Accounts receivable consist of the following:

	September 30, 2013			December 31, 2012
Trade customers	$	404,678		$	388,949
Affiliates	333			258
Allowance for doubtful accounts	(9,832		)	(11,172		)
	395,179			378,035
Federal and state taxes	20,421			4,011
Other	17,425			18,113
Accounts receivable, net	$	433,025		$	400,159

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Basis of Financial Statements Basis (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Windfall tax benefits from share-based payment arrangements	$ 5,056	$ 7,792
Revision, from operating activities to financing activities
Windfall tax benefits from share-based payment arrangements		$ 7,792

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Current Marketable Securities (Tables)

9 Months Ended

Sep. 30, 2013

Investments, Debt and Equity Securities [Abstract]

Marketable Securities

The Company’s investments in current marketable securities were classified as follows:

	September 30, 2013		December 31, 2012
Available-for-sale securities	$	120,602	$	—
Held-to-maturity securities	4,995		124,873
Marketable securities	$	125,597	$	124,873

Available-for-sale Securities

The cost, gross unrealized gains, gross unrealized losses and fair value of the Company’s available-for-sale securities were as follows:

	September 30, 2013
	Cost		Gross Unrealized Gains		Gross Unrealized Losses (1)			Fair Value
Debt securities
Corporate bonds	$	11,888	$	191	$	(21	)	$	12,058
U.S. government debt (2)	26,400		23		(6		)	26,417
Asset-backed securities	82,109		27		(9		)	82,127
Total available-for-sale securities	$	120,397	$	241	$	(36	)	$	120,602

_____________

(1) All unrealized loss positions were held at a loss for less than 12 months.

(2) U.S. Treasury obligations, U.S. government agency obligations and U.S government agency mortgage-backed securities.

Schedule of Realized Gain (Loss)

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Derivative Instruments (Tables)

9 Months Ended

Sep. 30, 2013

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Fair Values of Derivatives Instruments in Consolidated Balance Sheets

The fair values of derivative instruments in the Company's consolidated balance sheets were as follows:

	Derivative Assets
	Balance Sheet Location	Fair Value as of
		September 30, 2013		December 31, 2012
Designated as hedging instruments
Commodity forward contracts	Accounts receivable, net	$	3,208	$	13,032
Not designated as hedging instruments
Commodity forward contracts	Accounts receivable, net	2,541		1,395
Total derivative assets		$	5,749	$	14,427

	Derivative Liabilities
	Balance Sheet Location	Fair Value as of
		September 30, 2013		December 31, 2012
Designated as hedging instruments
Commodity forward contracts	Accrued liabilities	$	—	$	399
Not designated as hedging instruments
Commodity forward contracts	Accrued liabilities	2,090		13,295
Total derivative liabilities		$	2,090	$	13,694

Impact of Derivatives Instruments Designated as Fair Value Hedges

The following tables reflect the impact of derivative instruments designated as fair value hedges and the related hedged item on the Company's consolidated statements of operations. For the three and nine months ended September 30, 2013 and 2012, there was no material ineffectiveness with regard to the Company's qualifying fair value hedges.

Derivatives in Fair Value    Hedging Relationships	Location of Gain (Loss) Recognized in  Income on Derivative	Three Months Ended September 30,						Nine Months Ended September 30,
		2013			2012			2013			2012
Commodity forward contracts	Cost of sales	$	(232	)	$	(515	)	$	(342	)	$	12,345
Hedged Items in Fair Value    Hedging Relationships	Location of Gain (Loss) Recognized in  Income on Hedged Items	Three Months Ended September 30,						Nine Months Ended September 30,
		2013			2012			2013			2012
Firm commitment designated    as the hedged item	Cost of sales	$	236		$	515		$	15		$	(13,546	)

Impact of Derivative Instruments Not Designated as Fair Value Hedges

The impact of derivative instruments that have not been designated as hedges on the Company's consolidated statements of operations were as follows:

Derivatives Not Designated as    Hedging Instruments	Location of Gain (Loss) Recognized in  Income on Derivative	Three Months Ended September 30,				Nine Months Ended September 30,
		2013		2012		2013		2012
Commodity forward contracts	Cost of sales	$	4,854	$	249	$	9,897	$	(783	)

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Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Segment Reporting Information [Line Items]
Net external sales	$ 1,004,165	$ 821,175	$ 2,807,859	$ 2,770,000
Income (loss) from operations	266,602	142,517	695,884	459,120
Depreciation and amortization	40,728	38,424	116,294	109,601
Other (expense) income, net	(287)	1,222	3,137	3,676
Provision for (benefit from) income taxes	92,728	38,236	244,647	146,183
Capital expenditures	200,418	94,895	498,290	235,463
Olefins
Segment Reporting Information [Line Items]
Net external sales	679,339	539,785	1,885,525	1,944,775
Income (loss) from operations	237,239	124,452	585,958	409,550
Depreciation and amortization	26,515	27,070	76,415	74,903
Other (expense) income, net	728	806	5,889	2,764
Provision for (benefit from) income taxes	82,553	36,092	208,170	130,612
Capital expenditures	27,577	46,867	105,656	92,168
Vinyls
Segment Reporting Information [Line Items]
Net external sales	324,826	281,390	922,334	825,225
Income (loss) from operations	39,554	24,059	136,123	67,724
Depreciation and amortization	14,089	11,232	39,507	34,330
Other (expense) income, net	(742)	146	(1,687)	115
Provision for (benefit from) income taxes	10,710	6,556	44,120	18,989
Capital expenditures	172,565	47,001	391,864	139,836
Corporate and Other
Segment Reporting Information [Line Items]
Income (loss) from operations	(10,191)	(5,994)	(26,197)	(18,154)
Depreciation and amortization	124	122	372	368
Other (expense) income, net	(273)	270	(1,065)	797
Provision for (benefit from) income taxes	(535)	(4,412)	(7,643)	(3,418)
Capital expenditures	276	1,027	770	3,459
Polyethylene | Olefins
Segment Reporting Information [Line Items]
Net external sales	460,105	431,614	1,294,566	1,275,057
Ethylene, Styrene And Other | Olefins
Segment Reporting Information [Line Items]
Net external sales	219,234	108,171	590,959	669,718
PVC, Caustic Soda And Other | Vinyls
Segment Reporting Information [Line Items]
Net external sales	212,041	191,310	612,391	569,316
Building Products | Vinyls
Segment Reporting Information [Line Items]
Net external sales	112,785	90,080	309,943	255,909
Intersegment sales
Segment Reporting Information [Line Items]
Net external sales	85,857	77,162	231,718	248,838
Intersegment sales | Olefins
Segment Reporting Information [Line Items]
Net external sales	85,454	76,771	230,607	247,671
Intersegment sales | Vinyls
Segment Reporting Information [Line Items]
Net external sales	$ 403	$ 391	$ 1,111	$ 1,167

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Acquisitions (Tables)

9 Months Ended

Sep. 30, 2013

Business Combinations [Abstract]

Schedule of Recognized Identified Assets Acquired and Liabilities Assumed

Fair value of consideration transferred:
Cash	$	178,309
Preliminary allocation of consideration transferred to net assets acquired:
Accounts receivable (1)	$	17,695
Inventories	25,948
Property, plant and equipment	31,261
Intangible assets:
Customer relationships (weighted average life of 15 years)	57,600
Trademarks	5,200
Developed technology (weighted average life of 15 years)	18,900
Other intangibles (weighted average life of two years)	300
Current liabilities	(10,595		)
Other liabilities	(26		)
Total identifiable net assets	146,283
Goodwill (2)	32,026
Consideration transferred	$	178,309

Supplemental Noncash Investing Cash Flow Information

In conjunction with the acquisition, liabilities assumed consist of the following:

Fair value of assets acquired	$	188,930
Cash paid	(178,309		)
Liabilities assumed	$	10,621

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Segment Information (Additional Information) (Detail)	3 Months Ended
	Sep. 30, 2013 Segment
Segment Reporting [Abstract]
Number of segments	2

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Derivative Instruments (Impact of Derivative Instruments on Income) (Details) (Cost of Sales, USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Designated As Fair Value Hedges | Firm Commitment Derivative Items Designated As Hedged Item
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income on Derivative	$ 236	$ 515	$ 15	$ (13,546)
Designated As Fair Value Hedges | Forward Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income on Derivative	(232)	(515)	(342)	12,345
Derivatives Not Designated As Hedging Instruments | Forward Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income on Derivative	$ 4,854	$ 249	$ 9,897	$ (783)

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Long-Term Debt (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Long-term debt	$ 763,849	$ 763,761
3.60% Senior Notes Due 2022
Debt Instrument [Line Items]
Maturity	2022
Stated interest rate	3.60%
Senior notes	248,960	248,872
6 1/2% Senior Notes Due 2029
Debt Instrument [Line Items]
Maturity	2029
Stated interest rate	6.50%
Senior notes	100,000	100,000
6 3/4% Senior Notes Due 2032
Debt Instrument [Line Items]
Maturity	2032
Stated interest rate	6.75%
Senior notes	250,000	250,000
2035 GO Zone 6 1/2% Notes
Debt Instrument [Line Items]
Maturity	2035
Stated interest rate	6.50%
Senior notes	89,000	89,000
2035 IKE Zone 6 1/2% Notes
Debt Instrument [Line Items]
Maturity	2035
Stated interest rate	6.50%
Senior notes	65,000	65,000
Loan Related To Tax-Exempt Waste Disposal Revenue Bonds Due 2027
Debt Instrument [Line Items]
Maturity	2027
Non-current loan payable	$ 10,889	$ 10,889

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Current Marketable Securities Held-to-maturity Securities (Details) (Short-term corporate debt securities, USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Short-term corporate debt securities
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity securities	$ 4,995	$ 124,873

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Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	50,000,000	50,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	67,276,761	67,187,224
Common stock, held in treasury	506,525	284,493

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Stock-Based Compensation

9 Months Ended

Sep. 30, 2013

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock-Based Compensation

Stock-Based Compensation

Under the Westlake Chemical Corporation 2013 Omnibus Incentive Plan (as amended and restated, the "2013 Plan"), all employees and nonemployee directors of the Company, as well as certain individuals who have agreed to become the Company's employees, are eligible for awards. Shares of common stock may be issued as authorized in the 2013 Plan. At the discretion of the administrator of the 2013 Plan, employees and nonemployee directors may be granted awards in the form of stock options, stock appreciation rights, stock awards, restricted stock units or cash awards (any of which may be a performance award). Total stock-based compensation expense related to the 2013 Plan was $1,680 and $1,515 for the three months ended September 30, 2013 and 2012, respectively, and $4,804 and $4,640 for the nine months ended September 30, 2013 and 2012, respectively.

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Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement of Comprehensive Income [Abstract]
Net income	$ 170,290	$ 86,964	$ 439,453	$ 290,278
Pension and other post-retirement benefits liability
Pension and other post-retirement reserves adjustment (excluding amortization)	(489)	72	(978)	142
Amortization of benefits liability	695	584	2,004	1,747
Income tax provision on pension and other post-retirement benefits liability	(78)	(252)	(394)	(725)
Foreign currency translation adjustments	546	865	(844)	928
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	0	521	0	0
Available-for-sale investments
Unrealized holding gains (losses) on investments	205	339	205	14,582
Income tax provision on unrealized holding gains	(74)	(121)	(74)	(5,229)
Reclassification of net realized gain to net income	0	(306)	0	(10,538)
Other comprehensive income (loss)	805	1,702	(81)	907
Comprehensive income	$ 171,095	$ 88,666	$ 439,372	$ 291,185

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Income Taxes (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Income Tax Disclosure [Abstract]
Effective income tax rate	35.80%	33.50%
U.S. federal statutory income tax rate	35.00%	35.00%
Anticipated reductions to unrecognized tax benefits within next twelve months	$ 621

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Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Current assets
Cash and cash equivalents	$ 591,556	$ 790,078
Marketable Securities, Current	125,597	124,873
Accounts receivable, net	433,025	400,159
Inventories	451,571	399,298
Prepaid expenses and other current assets	18,809	14,700
Deferred income taxes	22,293	22,305
Total current assets	1,642,851	1,751,413
Property, plant and equipment, net	1,952,918	1,510,048
Equity investments	65,488	43,736
Other assets, net
Intangible assets, net	159,376	48,292
Deferred charges and other assets	102,816	58,707
Total other assets, net	262,192	106,999
Total assets	3,923,449	3,412,196
Current liabilities
Accounts payable	258,067	217,050
Accrued liabilities	174,619	181,460
Total current liabilities	432,686	398,510
Long-term debt	763,849	763,761
Deferred income taxes	410,166	326,290
Other liabilities	51,691	51,379
Total liabilities	1,658,392	1,539,940
Commitments and contingencies (Notes 7 and 16)
Stockholders' equity
Preferred stock, $0.01 par value, 50,000,000 shares authorized; no shares issued and outstanding	0	0
Common stock, $0.01 par value, 150,000,000 shares authorized; 67,276,761 and 67,187,224 shares issued at September 30, 2013 and December 31, 2012, respectively	673	672
Common stock, held in treasury, at cost; 506,525 and 284,493 shares at September 30, 2013 and December 31, 2012, respectively	(32,711)	(13,302)
Additional paid-in capital	509,295	496,254
Retained earnings	1,798,721	1,399,472
Accumulated other comprehensive loss	(10,921)	(10,840)
Total stockholders' equity	2,265,057	1,872,256
Total liabilities and stockholders' equity	$ 3,923,449	$ 3,412,196

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Long-Term Debt (Revolving Credit Facility) (Details) (Line of Credit, USD $) In Thousands, unless otherwise specified	3 Months Ended
	Sep. 30, 2013
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 400,000
Percentage of commitment on borrowing availability	0.375%
Letters of credit outstanding	16,921
Remaining borrowing capacity	383,079
Minimum
Line of Credit Facility [Line Items]
Increase in credit facility borrowings	25,000
Maximum
Line of Credit Facility [Line Items]
Increase in credit facility borrowings	$ 150,000
Plus Libor | Minimum
Line of Credit Facility [Line Items]
Percentage added to basis to find interest rate	1.75%
Plus Libor | Maximum
Line of Credit Facility [Line Items]
Percentage added to basis to find interest rate	2.25%
Plus Base Rate | Minimum
Line of Credit Facility [Line Items]
Percentage added to basis to find interest rate	0.25%
Plus Base Rate | Maximum
Line of Credit Facility [Line Items]
Percentage added to basis to find interest rate	0.75%

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Guarantor Disclosures (Additional Information) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Sep. 30, 2013
Condensed Financial Statements, Captions [Line Items]
Ownership interest in guarantor subsidiaries	100.00%
3.60% Senior Notes Due 2022
Condensed Financial Statements, Captions [Line Items]
Stated interest rate	3.60%
Maturity	2022
Minimum debt amount guaranteed by subsidiaries	$ 5,000

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Accounts Receivable (Tables)

9 Months Ended

Sep. 30, 2013

Accounts Receivable, Net [Abstract]

Schedule Of Accounts Receivable

Accounts receivable consist of the following:

	September 30, 2013			December 31, 2012
Trade customers	$	404,678		$	388,949
Affiliates	333			258
Allowance for doubtful accounts	(9,832		)	(11,172		)
	395,179			378,035
Federal and state taxes	20,421			4,011
Other	17,425			18,113
Accounts receivable, net	$	433,025		$	400,159

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Segment Information

9 Months Ended

Sep. 30, 2013

Segment Reporting [Abstract]

Segment Information

Segment Information

The Company operates in two principal business segments: Olefins and Vinyls. These segments are strategic business units that offer a variety of different products. The Company manages each segment separately as each business requires different technology and marketing strategies.

	Three Months Ended September 30,						Nine Months Ended September 30,
	2013			2012			2013			2012
Net external sales
Olefins
Polyethylene	$	460,105		$	431,614		$	1,294,566		$	1,275,057
Styrene, feedstock and other	219,234			108,171			590,959			669,718
Total Olefins	679,339			539,785			1,885,525			1,944,775
Vinyls
PVC, caustic soda and other	212,041			191,310			612,391			569,316
Building products	112,785			90,080			309,943			255,909
Total Vinyls	324,826			281,390			922,334			825,225
	$	1,004,165		$	821,175		$	2,807,859		$	2,770,000
Intersegment sales
Olefins	$	85,454		$	76,771		$	230,607		$	247,671
Vinyls	403			391			1,111			1,167
	$	85,857		$	77,162		$	231,718		$	248,838
Income (loss) from operations
Olefins	$	237,239		$	124,452		$	585,958		$	409,550
Vinyls	39,554			24,059			136,123			67,724
Corporate and other	(10,191		)	(5,994		)	(26,197		)	(18,154		)
	$	266,602		$	142,517		$	695,884		$	459,120
Depreciation and amortization
Olefins	$	26,515		$	27,070		$	76,415		$	74,903
Vinyls	14,089			11,232			39,507			34,330
Corporate and other	124			122			372			368
	$	40,728		$	38,424		$	116,294		$	109,601
Other income (expense), net
Olefins	$	728		$	806		$	5,889		$	2,764
Vinyls	(742		)	146			(1,687		)	115
Corporate and other	(273		)	270			(1,065		)	797
	$	(287	)	$	1,222		$	3,137		$	3,676
Provision for (benefit from) income taxes
Olefins	$	82,553		$	36,092		$	208,170		$	130,612
Vinyls	10,710			6,556			44,120			18,989
Corporate and other	(535		)	(4,412		)	(7,643		)	(3,418		)
	$	92,728		$	38,236		$	244,647		$	146,183

	Three Months Ended September 30,				Nine Months Ended September 30,
	2013		2012		2013		2012
Capital expenditures
Olefins	$	27,577	$	46,867	$	105,656	$	92,168
Vinyls	172,565		47,001		391,864		139,836
Corporate and other	276		1,027		770		3,459
	$	200,418	$	94,895	$	498,290	$	235,463

A reconciliation of total segment income from operations to consolidated income before income taxes is as follows:

	Three Months Ended September 30,						Nine Months Ended September 30,
	2013			2012			2013			2012
Income from operations	$	266,602		$	142,517		$	695,884		$	459,120
Interest expense	(3,297		)	(11,934		)	(14,921		)	(35,682		)
Debt retirement costs	—			(7,082		)	—			(7,082		)
Gain from sales of equity securities	—			477			—			16,429
Other (expense) income, net	(287		)	1,222			3,137			3,676
Income before income taxes	$	263,018		$	125,200		$	684,100		$	436,461

	September 30, 2013		December 31, 2012
Total assets
Olefins	$	1,560,303	$	1,439,308
Vinyls	1,577,549		1,030,912
Corporate and other	785,597		941,976
	$	3,923,449	$	3,412,196

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Current Marketable Securities Maturity Periods for Investments (Details)	9 Months Ended
	Sep. 30, 2013
Corporate bonds | Minimum
Schedule of Available-for-sale Securities [Line Items]
Investment maturity period	1 year
Corporate bonds | Maximum
Schedule of Available-for-sale Securities [Line Items]
Investment maturity period	5 years
US Government Agencies Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment maturity period	1 year
Mortgage-backed securities | Minimum
Schedule of Available-for-sale Securities [Line Items]
Investment maturity period	4 years
Mortgage-backed securities | Maximum
Schedule of Available-for-sale Securities [Line Items]
Investment maturity period	26 years
Asset-backed securities | Minimum
Schedule of Available-for-sale Securities [Line Items]
Investment maturity period	2 years
Asset-backed securities | Maximum
Schedule of Available-for-sale Securities [Line Items]
Investment maturity period	5 years

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Guarantor Disclosures (Condensed Consolidating Financial Information Statement of Operations) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Condensed Financial Statements, Captions [Line Items]
Net sales	$ 1,004,165	$ 821,175	$ 2,807,859	$ 2,770,000
Cost of sales	699,694	648,996	2,002,092	2,223,288
Gross profit	304,471	172,179	805,767	546,712
Selling, general and administrative expenses	37,869	29,662	109,883	87,592
Income from operations	266,602	142,517	695,884	459,120
Interest expense	(3,297)	(11,934)	(14,921)	(35,682)
Debt retirement costs	0	(7,082)	0	(7,082)
Gain from sales of equity securities	0	477	0	16,429
Other income (expense), net	(287)	1,222	3,137	3,676
Income before income taxes	263,018	125,200	684,100	436,461
Provision for (benefit from) income taxes	92,728	38,236	244,647	146,183
Equity in net income of subsidiaries	0	0	0	0
Net income	170,290	86,964	439,453	290,278
Comprehensive income (loss)	171,095	88,666	439,372	291,185
Westlake Chemical Corporation
Condensed Financial Statements, Captions [Line Items]
Net sales	0	0	0	0
Cost of sales	0	0	0	0
Gross profit	0	0	0	0
Selling, general and administrative expenses	514	498	1,576	1,500
Income from operations	(514)	(498)	(1,576)	(1,500)
Interest expense	(3,292)	(11,919)	(14,882)	(35,652)
Debt retirement costs		(7,082)		(7,082)
Gain from sales of equity securities		0		1
Other income (expense), net	3,585	4,556	7,490	12,044
Income before income taxes	(221)	(14,943)	(8,968)	(32,189)
Provision for (benefit from) income taxes	(70)	(4,498)	(3,202)	(11,105)
Equity in net income of subsidiaries	170,441	97,409	445,219	311,362
Net income	170,290	86,964	439,453	290,278
Comprehensive income (loss)	171,095	88,666	439,372	291,185
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net sales	992,413	809,164	2,777,280	2,738,180
Cost of sales	689,388	638,892	1,976,131	2,197,300
Gross profit	303,025	170,272	801,149	540,880
Selling, general and administrative expenses	35,714	27,601	103,478	81,288
Income from operations	267,311	142,671	697,671	459,592
Interest expense	(5)	(15)	(39)	(30)
Debt retirement costs		0		0
Gain from sales of equity securities		477		16,428
Other income (expense), net	(3,821)	(2,744)	(2,473)	(5,724)
Income before income taxes	263,485	140,389	695,159	470,266
Provision for (benefit from) income taxes	92,849	42,596	248,301	158,228
Equity in net income of subsidiaries	0	0	0	0
Net income	170,636	97,793	446,858	312,038
Comprehensive income (loss)	170,764	98,109	447,490	312,017
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net sales	13,337	13,876	37,561	37,154
Cost of sales	11,891	11,969	32,943	31,322
Gross profit	1,446	1,907	4,618	5,832
Selling, general and administrative expenses	1,641	1,563	4,829	4,804
Income from operations	(195)	344	(211)	1,028
Interest expense	0	0	0	0
Debt retirement costs		0		0
Gain from sales of equity securities		0		0
Other income (expense), net	(51)	(590)	(1,880)	(2,644)
Income before income taxes	(246)	(246)	(2,091)	(1,616)
Provision for (benefit from) income taxes	(51)	138	(452)	(940)
Equity in net income of subsidiaries	0	0	0	0
Net income	(195)	(384)	(1,639)	(676)
Comprehensive income (loss)	351	481	(2,483)	252
Eliminations
Condensed Financial Statements, Captions [Line Items]
Net sales	(1,585)	(1,865)	(6,982)	(5,334)
Cost of sales	(1,585)	(1,865)	(6,982)	(5,334)
Gross profit	0	0	0	0
Selling, general and administrative expenses	0	0	0	0
Income from operations	0	0	0	0
Interest expense	0	0	0	0
Debt retirement costs		0		0
Gain from sales of equity securities		0		0
Other income (expense), net	0	0	0	0
Income before income taxes	0	0	0	0
Provision for (benefit from) income taxes	0	0	0	0
Equity in net income of subsidiaries	(170,441)	(97,409)	(445,219)	(311,362)
Net income	(170,441)	(97,409)	(445,219)	(311,362)
Comprehensive income (loss)	$ (171,115)	$ (98,590)	$ (445,007)	$ (312,269)

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Derivative Instruments (Fair Values of Derivative Instruments in Consolidated Balance Sheets) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Accrued Liabilities
Derivatives, Fair Value [Line Items]
Total derivative liabilities	$ 2,090	$ 13,694
Accounts Receivable
Derivatives, Fair Value [Line Items]
Total derivative assets	5,749	14,427
Forward Contracts [Member] | Accrued Liabilities
Derivatives, Fair Value [Line Items]
Designated as hedging instruments, Derivative Liabilities	0	399
Not designated as hedging instruments, Derivative Liabilities	2,090	13,295
Forward Contracts [Member] | Accounts Receivable
Derivatives, Fair Value [Line Items]
Designated as hedging instruments, Derivative Assets	3,208	13,032
Not designated as hedging instruments, Derivative Assets	$ 2,541	$ 1,395

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Accumulated Other Comprehensive Income Reclassifications in AOCI (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012	Sep. 30, 2013		Sep. 30, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income before income taxes	$ 263,018		$ 125,200	$ 684,100		$ 436,461
Provision for income taxes	(92,728)		(38,236)	(244,647)		(146,183)
Net income	170,290		86,964	439,453		290,278
Accumulated Defined Benefit Plans Adjustment | Reclassification out of Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Prior service costs	(95)	[1]		(286)	[1]
Net loss	(600)	[1]		(1,718)	[1]
Income before income taxes	(695)			(2,004)
Provision for income taxes	267			771
Net income	$ (428)			$ (1,233)

[1] These accumulated other comprehensive loss components are included in the computation of net periodic benefit cost. For additional information, please read Note 8 (Employee Benefits) to the financial statements included in the 2012 Form 10-K.

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Goodwill (Tables)

9 Months Ended

Sep. 30, 2013

Goodwill [Abstract]

Schedule of Goodwill

The changes in the carrying amount of goodwill for the nine months ended September 30, 2013 were as follows:

	Olefins Segment		Vinyls Segment		Total
Balance at December 31, 2012	$	29,990	$	—	$	29,990
Goodwill acquired during the period	—		32,026		32,026
Balance at September 30, 2013	$	29,990	$	32,026	$	62,016

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Pension and Post-Retirement Benefit Costs (Tables)

9 Months Ended

Sep. 30, 2013

Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]

Components of Net Periodic Benefit Cost

Components of net periodic benefit cost are as follows:

	Three Months Ended September 30,										Nine Months Ended September 30,
	Pension						Post-retirement Healthcare				Pension						Post-retirement Healthcare
	2013			2012			2013		2012		2013			2012			2013		2012
Service cost	$	275		$	250		$	2	$	2	$	815		$	754		$	7	$	7
Interest cost	515			645			147		185		1,531			1,936			442		555
Expected return on plan assets	(713		)	(623		)	—		—		(2,140		)	(1,867		)	—		—
Amortization of prior    service cost	74			74			21		21		223			223			63		63
Amortization of net loss	510			445			90		44		1,449			1,329			269		132
Net periodic benefit cost	$	661		$	791		$	260	$	252	$	1,878		$	2,375		$	781	$	757

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Accumulated Other Comprehensive Income (Tables)

9 Months Ended

Sep. 30, 2013

Equity [Abstract]

Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]

Changes in accumulated other comprehensive income (loss) by component for the nine months ended September 30, 2013 were as follows:

	Benefits Liability, Net of Tax			Cumulative Foreign Currency Exchange			Net Unrealized Holding Gains on Investments, Net of Tax		Total
Balances at December 31, 2012	$	(16,351	)	$	5,511		$	—	$	(10,840	)
Other comprehensive (loss) income before    reclassifications	(601		)	(844		)	131		(1,314		)
Amounts reclassified from accumulated other    comprehensive loss	1,233			—			—		1,233
Net other comprehensive income (loss) for the period	632			(844		)	131		(81		)
Balances at September 30, 2013	$	(15,719	)	$	4,667		$	131	$	(10,921	)

Reclassification out of Accumulated Other Comprehensive Income [Table Text Block]

The following table provides the details of the amounts reclassified from accumulated other comprehensive income (loss) into net income in the consolidated statements of operations for the three and nine months ended September 30, 2013:

Details about Accumulated Other Comprehensive    Income (Loss) Components	Location of Reclassification (Income (Expense)) in Consolidated Statements of Operations	Three Months Ended September 30, 2013			Nine Months Ended September 30, 2013
Amortization of pension and other post-retirement items
Prior service costs	(1)	$	(95	)	$	(286	)
Net loss	(1)	(600		)	(1,718		)
		(695		)	(2,004		)
	Provision for income taxes	267			771
Total reclassifications for the period		$	(428	)	$	(1,233	)

_____________

(1) These accumulated other comprehensive loss components are included in the computation of net periodic benefit cost. For additional information, please read Note 8 (Employee Benefits) to the financial statements included in the 2012 Form 10-K.

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Long-Term Debt

9 Months Ended

Sep. 30, 2013

Debt Disclosure [Abstract]

Long-Term Debt

Long-Term Debt

Long-term debt consists of the following:

	September 30, 2013		December 31, 2012
3.60% senior notes due 2022	$	248,960	$	248,872
6 ½% senior notes due 2029	100,000		100,000
6 ¾% senior notes due 2032	250,000		250,000
6 ½% senior notes due 2035 (the "6 ½% GO Zone Senior Notes Due 2035")	89,000		89,000
6 ½% senior notes due 2035 (the "6 ½% IKE Zone Senior Notes Due 2035")	65,000		65,000
Loan related to tax-exempt waste disposal revenue bonds due 2027	10,889		10,889
Long-term debt, net	$	763,849	$	763,761

Revolving Credit Facility

The Company has a $400,000 senior secured revolving credit facility. The facility includes a provision permitting the Company to increase the size of the facility, up to four times, in increments of at least $25,000 each (up to a maximum of $150,000) under certain circumstances if lenders agree to commit to such an increase. At September 30, 2013, the Company had no borrowings outstanding under the revolving credit facility. Any borrowings under the facility will bear interest at either LIBOR plus a spread ranging from 1.75% to 2.25% or a base rate plus a spread ranging from 0.25% to 0.75%. The revolving credit facility also requires an unused commitment fee of 0.375% per annum. All interest rates under the facility are subject to monthly grid pricing adjustments based on prior month average daily loan availability. The revolving credit facility matures on September 16, 2016. As of September 30, 2013, the Company had outstanding letters of credit totaling $16,921 and borrowing availability of $383,079 under the revolving credit facility.

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Pension and Post-Retirement Benefit Costs (Components of Net Periodic Benefit Cost) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Pension
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 275	$ 250	$ 815	$ 754
Interest cost	515	645	1,531	1,936
Expected return on plan assets	(713)	(623)	(2,140)	(1,867)
Amortization of prior service cost	74	74	223	223
Amortization of net loss	510	445	1,449	1,329
Net periodic benefit cost	661	791	1,878	2,375
Post-Retirement Healthcare
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	2	7	7
Interest cost	147	185	442	555
Expected return on plan assets	0	0	0	0
Amortization of prior service cost	21	21	63	63
Amortization of net loss	90	44	269	132
Net periodic benefit cost	$ 260	$ 252	$ 781	$ 757

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Inventories (Tables)

9 Months Ended

Sep. 30, 2013

Inventory Disclosure [Abstract]

Schedule Of Inventory

Inventories consist of the following:

	September 30, 2013		December 31, 2012
Finished products	$	198,762	$	200,940
Feedstock, additives and chemicals	194,558		143,912
Materials and supplies	58,251		54,446
Inventories	$	451,571	$	399,298

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Current Marketable Securities Marketable Securities (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Investments, Debt and Equity Securities [Abstract]
Available-for-sale securities	$ 120,602	$ 0
Marketable Securities, Current	$ 125,597	$ 124,873

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Fair Value Measurements

9 Months Ended

Sep. 30, 2013

Fair Value Disclosures [Abstract]

Fair Value Measurements

Fair Value Measurements

The Company reports certain assets and liabilities at fair value, which is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). Under the accounting guidance for fair value measurements, inputs used to measure fair value are classified in one of three levels:

Level 1: Quoted market prices in active markets for identical assets or liabilities.

Level 2: Observable market-based inputs or unobservable inputs that are corroborated by market data.

Level 3: Unobservable inputs that are not corroborated by market data.

The following tables summarize, by level within the fair value hierarchy, the Company's assets and liabilities that were accounted for at fair value on a recurring basis:

	September 30, 2013
	Level 1			Level 2			Total
Derivative instruments
Risk management assets - Commodity forward contracts	$	1,808		$	3,941		$	5,749
Risk management liabilities - Commodity forward contracts	(74		)	(2,016		)	(2,090		)
Firm commitments
Hedged portion of firm commitment	—			(3,208		)	(3,208		)
Marketable securities
Available-for-sale securities	14,998			105,604			120,602
	December 31, 2012
	Level 1			Level 2			Total
Derivative instruments
Risk management assets - Commodity forward contracts	$	1,395		$	13,032		$	14,427
Risk management liabilities - Commodity forward contracts	—			(13,694		)	(13,694		)
Firm commitments
Hedged portion of firm commitment	—			399			399
Hedged portion of firm commitment	—			(13,032		)	(13,032		)

The Level 2 measurements for the Company's commodity contracts are derived using forward curves supplied by industry-recognized and unrelated third-party services. The Level 2 measurements for the Company's available-for-sale securities are derived using market-based pricing provided by unrelated third-party services.

There were no transfers in and out of Levels 1 and 2 of the fair value hierarchy for the nine months ended September 30, 2013 and 2012.

In addition to the financial assets and liabilities above, the Company has other financial assets and liabilities subject to fair value measures. These financial assets and liabilities include cash and cash equivalents, accounts receivable, net, accounts payable and long-term debt, all of which are recorded at carrying value. The amounts reported in the consolidated balance sheets for cash and cash equivalents, accounts receivable, net and accounts payable approximate their fair value due to the short maturities of these instruments. The carrying and fair values of the Company's long-term debt are summarized in the table below. The Company's long-term debt instruments are publicly-traded. A market approach, based upon quotes from financial reporting services, is used to measure the fair value of the Company's long-term debt. Because the Company's long-term debt instruments may not be actively traded, the inputs used to measure the fair value of the Company's long-term debt are classified as Level 2 inputs within the fair value hierarchy.

	September 30, 2013				December 31, 2012
	Carrying Value		Fair Value		Carrying Value		Fair Value
3.60% senior notes due 2022	$	248,960	$	238,228	$	248,872	$	251,125
6 ½% senior notes due 2029	100,000		107,800		100,000		119,738
6 ¾% senior notes due 2032	250,000		267,465		250,000		283,168
6 ½% GO Zone Senior Notes Due 2035	89,000		94,209		89,000		102,095
6 ½% IKE Zone Senior Notes Due 2035	65,000		68,804		65,000		74,564
Loan related to tax-exempt waste disposal revenue    bonds due 2027	10,889		10,889		10,889		10,889

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Goodwill (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Goodwill [Line Items]
Goodwill	$ 62,016	$ 29,990
Goodwill, Acquired During Period	32,026
Olefins
Goodwill [Line Items]
Goodwill	29,990	29,990
Goodwill, Acquired During Period	0
Vinyls
Goodwill [Line Items]
Goodwill	32,026	0
Goodwill, Acquired During Period	$ 32,026

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Other Assets

9 Months Ended

Sep. 30, 2013

Other Assets [Abstract]

Other Assets

Other Assets

Amortization expense on intangible and other assets of $8,634 and $8,717 is included in the consolidated statements of operations for the three months ended September 30, 2013 and 2012, respectively. Amortization expense on intangible and other assets of $21,392 and $20,135 is included in the consolidated statements of operations for the nine months ended September 30, 2013 and 2012, respectively.

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Basis of Financial Statements

9 Months Ended

Sep. 30, 2013

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Basis of Financial Statements

Basis of Financial Statements

The accompanying unaudited consolidated interim financial statements were prepared in accordance with the rules and regulations of the Securities and Exchange Commission (the "SEC") for interim periods. Accordingly, certain information and footnotes required for complete financial statements under generally accepted accounting principles in the United States ("U.S. GAAP") have not been included. These interim consolidated financial statements should be read in conjunction with the December 31, 2012 financial statements and notes thereto of Westlake Chemical Corporation (the "Company") included in the annual report on Form 10-K for the fiscal year ended December 31, 2012 (the "2012 Form 10-K"), filed with the SEC on February 22, 2013. These financial statements have been prepared in conformity with the accounting principles and practices as disclosed in the notes to the consolidated financial statements of the Company for the fiscal year ended December 31, 2012.

In the opinion of the Company's management, the accompanying unaudited consolidated interim financial statements reflect all adjustments (consisting only of normal recurring adjustments) that are necessary for a fair statement of the Company's financial position as of September 30, 2013, its results of operations for the three and nine months ended September 30, 2013 and 2012 and the changes in its cash position for the nine months ended September 30, 2013 and 2012.

Results of operations and changes in cash position for the interim periods presented are not necessarily indicative of the results that will be realized for the fiscal year ending December 31, 2013 or any other interim period. The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities. Actual results could differ from those estimates.

Revisions

The consolidated statement of cash flows for the nine months ended September 30, 2012 has been revised to correct the presentation of windfall tax benefits from share-based compensation of $7,792 in financing activities, instead of operating activities. The Company has determined that this revision was immaterial to the Company's previously issued financial statements.

Recent Accounting Pronouncements

Disclosures about Offsetting Assets and Liabilities

In December 2011, the Financial Accounting Standards Board ("FASB") issued an accounting standards update on disclosures for offsetting assets and liabilities. The new accounting guidance requires companies to disclose both gross and net information about (1) instruments and transactions eligible for offset in the statement of financial position, and (2) instruments and transactions subject to an agreement similar to a master netting arrangement. The FASB issued another accounting standards update clarifying the scope of the assets and liabilities offset disclosure requirements in January 2013. The effective date of the disclosure requirements remains unchanged. The Company adopted the new guidance as of January 1, 2013, and the adoption did not have an impact on the Company's consolidated financial position, results of operations or cash flows.

Testing Indefinite-Lived Intangible Assets for Impairment

In July 2012, the FASB issued an accounting standards update to simplify how entities test indefinite-lived intangible assets for impairment and to improve consistency in impairment testing guidance among long-lived asset categories. The new accounting guidance provides an entity with an option to first assess qualitative factors to determine whether it is more likely than not that an indefinite-lived intangible asset is impaired as a basis for determining whether it is necessary to perform the quantitative impairment test under current accounting guidance. If an entity concludes that it is not more likely than not that the indefinite-lived intangible asset is impaired, then the entity is not required to take further action. However, if an entity concludes otherwise, then it is required to determine the fair value of the indefinite-lived intangible asset and perform the quantitative impairment test by comparing the fair value with the carrying amount in accordance with current accounting guidance. Also under this new accounting guidance, an entity has the option to bypass the qualitative assessment for any indefinite-lived intangible asset in any period and proceed directly to performing the quantitative impairment test, but may resume performing the qualitative assessment in any subsequent period. The Company adopted the new indefinite-lived intangible assets test guidance as of January 1, 2013, and the adoption did not have a material impact on the Company's consolidated financial position, results of operations or cash flows.

Reclassifications Out of Accumulated Other Comprehensive Income

In February 2013, the FASB issued an accounting standards update on reporting items reclassified out of accumulated other comprehensive income. The new accounting guidance requires companies to present either parenthetically on the face of the financial statements or in the notes, significant amounts reclassified from each component of accumulated other comprehensive income and the income statement line items affected by the reclassification, with certain exceptions. The Company adopted the new guidance as of January 1, 2013, and the adoption did not have an impact on the Company's consolidated financial position, results of operations or cash flows.

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Stock-Based Compensation (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-based compensation expense	$ 1,680	$ 1,515	$ 4,804	$ 4,640

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Inventories (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Inventory Disclosure [Abstract]
Finished products	$ 198,762	$ 200,940
Feedstock, additives and chemicals	194,558	143,912
Materials and supplies	58,251	54,446
Inventories	$ 451,571	$ 399,298

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Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2013

Fair Value Disclosures [Abstract]

Summary Of Assets And Liabilities Accounted At Fair Value On A Recurring Basis

The following tables summarize, by level within the fair value hierarchy, the Company's assets and liabilities that were accounted for at fair value on a recurring basis:

	September 30, 2013
	Level 1			Level 2			Total
Derivative instruments
Risk management assets - Commodity forward contracts	$	1,808		$	3,941		$	5,749
Risk management liabilities - Commodity forward contracts	(74		)	(2,016		)	(2,090		)
Firm commitments
Hedged portion of firm commitment	—			(3,208		)	(3,208		)
Marketable securities
Available-for-sale securities	14,998			105,604			120,602
	December 31, 2012
	Level 1			Level 2			Total
Derivative instruments
Risk management assets - Commodity forward contracts	$	1,395		$	13,032		$	14,427
Risk management liabilities - Commodity forward contracts	—			(13,694		)	(13,694		)
Firm commitments
Hedged portion of firm commitment	—			399			399
Hedged portion of firm commitment	—			(13,032		)	(13,032		)

Summary Of Carrying And Fair Values Of Long-Term Debt

The carrying and fair values of the Company's long-term debt are summarized in the table below. The Company's long-term debt instruments are publicly-traded. A market approach, based upon quotes from financial reporting services, is used to measure the fair value of the Company's long-term debt. Because the Company's long-term debt instruments may not be actively traded, the inputs used to measure the fair value of the Company's long-term debt are classified as Level 2 inputs within the fair value hierarchy.

	September 30, 2013				December 31, 2012
	Carrying Value		Fair Value		Carrying Value		Fair Value
3.60% senior notes due 2022	$	248,960	$	238,228	$	248,872	$	251,125
6 ½% senior notes due 2029	100,000		107,800		100,000		119,738
6 ¾% senior notes due 2032	250,000		267,465		250,000		283,168
6 ½% GO Zone Senior Notes Due 2035	89,000		94,209		89,000		102,095
6 ½% IKE Zone Senior Notes Due 2035	65,000		68,804		65,000		74,564
Loan related to tax-exempt waste disposal revenue    bonds due 2027	10,889		10,889		10,889		10,889

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Acquisitions (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		0 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	May 01, 2013 Pipe and Foundation Group lb	Sep. 30, 2013 Pipe and Foundation Group
Business Acquisition [Line Items]
Annual production capacity of PVC pipe and fittings					150,000,000
Cash paid for purchase			$ 178,309	$ 0	$ 178,309
Net sales	1,004,165	821,175	2,807,859	2,770,000
Net income	170,290	86,964	439,453	290,278
Acquisition-related costs						$ 1,124

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Earnings per Share (Additional Information) (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Earnings Per Share [Abstract]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	68,662	168,362	57,759	293,062

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Pension and Post-Retirement Benefit Costs

9 Months Ended

Sep. 30, 2013

Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]

Pension and Post-Retirement Benefit Costs

Pension and Post-Retirement Benefit Costs

Components of net periodic benefit cost are as follows:

	Three Months Ended September 30,										Nine Months Ended September 30,
	Pension						Post-retirement Healthcare				Pension						Post-retirement Healthcare
	2013			2012			2013		2012		2013			2012			2013		2012
Service cost	$	275		$	250		$	2	$	2	$	815		$	754		$	7	$	7
Interest cost	515			645			147		185		1,531			1,936			442		555
Expected return on plan assets	(713		)	(623		)	—		—		(2,140		)	(1,867		)	—		—
Amortization of prior    service cost	74			74			21		21		223			223			63		63
Amortization of net loss	510			445			90		44		1,449			1,329			269		132
Net periodic benefit cost	$	661		$	791		$	260	$	252	$	1,878		$	2,375		$	781	$	757

The Company contributed $776 and $2,283 to the Salaried pension plan in the first nine months of 2013 and 2012, respectively, and contributed $640 and $1,542 to the Wage pension plan in the first nine months of 2013 and 2012, respectively. The Company expects to make additional contributions of $388 to the Salaried pension plan and $290 to the Wage pension plan during the fiscal year ending December 31, 2013.

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Derivative Instruments

9 Months Ended

Sep. 30, 2013

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Derivative Instruments

Derivative Instruments

Commodity Risk Management

The Company uses derivative instruments to reduce price volatility risk on raw materials and products as a substantial portion of its raw materials and products are commodities whose prices fluctuate as market supply and demand fundamentals change. Business strategies to protect against such instability include ethylene product feedstock flexibility and moving downstream into the olefins and vinyls products where pricing is more stable. The Company does not use derivative instruments to engage in speculative activities.

For derivative instruments that are designated and qualify as fair value hedges, the gains or losses on the derivative instruments, as well as the offsetting losses or gains on the hedged items attributable to the hedged risk, were included in cost of sales in the consolidated statements of operations for the three and nine months ended September 30, 2013 and 2012. As of September 30, 2013, the Company had 10,710,000 gallons of feedstock forward contracts designated as fair value hedges.

Gains and losses from changes in the fair value of derivative instruments that are not designated as hedging instruments were included in cost of sales in the consolidated statements of operations for the three and nine months ended September 30, 2013 and 2012.

The exposure on commodity derivatives used for price risk management includes the risk that the counterparty will not pay if the market declines below the established fixed price. In such case, the Company would lose the benefit of the derivative differential on the volume of the commodities covered. In any event, the Company would continue to receive the market price on the actual volume hedged. The Company also bears the risk that it could lose the benefit of market improvements over the fixed derivative price for the term and volume of the derivative instruments (as such improvements would accrue to the benefit of the counterparty).

Disclosures related to the Company's derivative assets and derivative liabilities subject to enforceable master netting arrangements have not been presented as they are not material to the Company's consolidated balance sheets at September 30, 2013 and December 31, 2012.

The fair values of derivative instruments in the Company's consolidated balance sheets were as follows:

	Derivative Assets
	Balance Sheet Location	Fair Value as of
		September 30, 2013		December 31, 2012
Designated as hedging instruments
Commodity forward contracts	Accounts receivable, net	$	3,208	$	13,032
Not designated as hedging instruments
Commodity forward contracts	Accounts receivable, net	2,541		1,395
Total derivative assets		$	5,749	$	14,427

	Derivative Liabilities
	Balance Sheet Location	Fair Value as of
		September 30, 2013		December 31, 2012
Designated as hedging instruments
Commodity forward contracts	Accrued liabilities	$	—	$	399
Not designated as hedging instruments
Commodity forward contracts	Accrued liabilities	2,090		13,295
Total derivative liabilities		$	2,090	$	13,694

The following tables reflect the impact of derivative instruments designated as fair value hedges and the related hedged item on the Company's consolidated statements of operations. For the three and nine months ended September 30, 2013 and 2012, there was no material ineffectiveness with regard to the Company's qualifying fair value hedges.

Derivatives in Fair Value    Hedging Relationships	Location of Gain (Loss) Recognized in  Income on Derivative	Three Months Ended September 30,						Nine Months Ended September 30,
		2013			2012			2013			2012
Commodity forward contracts	Cost of sales	$	(232	)	$	(515	)	$	(342	)	$	12,345
Hedged Items in Fair Value    Hedging Relationships	Location of Gain (Loss) Recognized in  Income on Hedged Items	Three Months Ended September 30,						Nine Months Ended September 30,
		2013			2012			2013			2012
Firm commitment designated    as the hedged item	Cost of sales	$	236		$	515		$	15		$	(13,546	)

The impact of derivative instruments that have not been designated as hedges on the Company's consolidated statements of operations were as follows:

Derivatives Not Designated as    Hedging Instruments	Location of Gain (Loss) Recognized in  Income on Derivative	Three Months Ended September 30,				Nine Months Ended September 30,
		2013		2012		2013		2012
Commodity forward contracts	Cost of sales	$	4,854	$	249	$	9,897	$	(783	)

See Note 10 for the fair value of the Company's derivative instruments.

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Acquisitions (Supplemental Noncash Investing Cash Flow Information) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended		0 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	May 01, 2013 Pipe and Foundation Group
Business Acquisition [Line Items]
Fair value of assets acquired			$ 188,930
Acquisition of business	(178,309)	0	(178,309)
Liabilities assumed			$ 10,621

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Commitments and Contingencies

9 Months Ended

Sep. 30, 2013

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

Commitments and Contingencies

The Company is subject to environmental laws and regulations that can impose civil and criminal sanctions and that may require it to mitigate the effects of contamination caused by the release or disposal of hazardous substances into the environment. Under one law, an owner or operator of property may be held strictly liable for remediating contamination without regard to whether that person caused the contamination, and without regard to whether the practices that resulted in the contamination were legal at the time they occurred. Because several of the Company's production sites have a history of industrial use, it is impossible to predict precisely what effect these legal requirements will have on the Company.

Contract Disputes with Goodrich and PolyOne. In connection with the 1990 and 1997 acquisitions of the Goodrich Corporation ("Goodrich") chemical manufacturing complex in Calvert City, Kentucky, Goodrich agreed to indemnify the Company for any liabilities related to preexisting contamination at the complex. For its part, the Company agreed to indemnify Goodrich for post-closing contamination caused by the Company's operations. The soil and groundwater at the complex, which does not include the Company's nearby PVC facility, had been extensively contaminated under Goodrich's operations. In 1993, Goodrich spun off the predecessor of PolyOne Corporation ("PolyOne"), and that predecessor assumed Goodrich's indemnification obligations relating to preexisting contamination.

In 2003, litigation arose among the Company, Goodrich and PolyOne with respect to the allocation of the cost of remediating contamination at the site. The parties settled this litigation in December 2007 and the case was dismissed. In the settlement the parties agreed that, among other things: (1) PolyOne would pay 100% of the costs (with specified exceptions), net of recoveries or credits from third parties, incurred with respect to environmental issues at the Calvert City site from August 1, 2007 forward; (2) either the Company or PolyOne might, from time to time in the future (but not more than once every five years), institute an arbitration proceeding to adjust that percentage; and (3) the Company and PolyOne would negotiate a new environmental remediation utilities and services agreement to cover the Company's provision to or on behalf of PolyOne of certain environmental remediation services at the site. The current environmental remediation activities at the Calvert City complex do not have a specified termination date but are expected to last for the foreseeable future. The costs incurred by the Company that have been invoiced to PolyOne to provide the environmental remediation services were $2,687 in 2012. By letter dated March 16, 2010, PolyOne notified the Company that it was initiating an arbitration proceeding under the settlement agreement. In this proceeding, PolyOne seeks to readjust the percentage allocation of costs and to recover approximately $1,400 from the Company in reimbursement of previously paid remediation costs. The arbitration is currently stayed.

Administrative Proceedings. There are several administrative proceedings in Kentucky involving the Company, Goodrich and PolyOne related to the same manufacturing complex in Calvert City. In 2003, the Kentucky Environmental and Public Protection Cabinet (the "Cabinet") re-issued Goodrich's Resource Conservation and Recovery Act ("RCRA") permit which requires Goodrich to remediate contamination at the Calvert City manufacturing complex. Both Goodrich and PolyOne challenged various terms of the permit in an attempt to shift Goodrich's clean-up obligations under the permit to the Company. The Company intervened in the proceedings. The Cabinet has suspended all corrective action under the RCRA permit in deference to a remedial investigation and feasibility study ("RIFS") being conducted pursuant to an Administrative Settlement Agreement ("AOC"), which became effective on December 9, 2009. See "Change in Regulatory Regime" below. The proceedings have been postponed. Periodic status conferences will be held to evaluate whether additional proceedings will be required.

Change in Regulatory Regime. In May 2009, the Cabinet sent a letter to the U.S. Environmental Protection Agency ("EPA") requesting the EPA's assistance in addressing contamination at the Calvert City site under the U.S. Comprehensive Environmental Response, Compensation, and Liability Act ("CERCLA"). In its response to the Cabinet also in May 2009, the EPA stated that it concurred with the Cabinet's request and would incorporate work previously conducted under the Cabinet's RCRA authority into the EPA's cleanup efforts under CERCLA. Since 1983, the EPA has been addressing contamination at an abandoned landfill adjacent to the Company's plant which had been operated by Goodrich and which was being remediated pursuant to CERCLA. During the past two years, the EPA has directed Goodrich and PolyOne to conduct additional investigation activities at the landfill and at the Company's plant. In June 2009, the EPA notified the Company that the Company may have potential liability under section 107(a) of CERCLA at its plant site. Liability under section 107(a) of CERCLA is strict and joint and several. The EPA also identified Goodrich and PolyOne, among others, as potentially responsible parties at the plant site. The Company negotiated, in conjunction with the other potentially responsible parties, the AOC and an order to conduct the RIFS. The parties submitted and received EPA approval for a RIFS work plan to implement the AOC. On July 12, 2013, the parties submitted separate draft RIFS reports to the EPA.

Monetary Relief. Except as noted above with respect to the settlement of the contract litigation among the Company, Goodrich and PolyOne, none of the court, the Cabinet nor the EPA has established any allocation of the costs of remediation among the various parties that are involved in the judicial and administrative proceedings discussed above. At this time, the Company is not able to estimate the loss or reasonable possible loss, if any, on the Company's financial statements that could result from the resolution of these proceedings. Any cash expenditures that the Company might incur in the future with respect to the remediation of contamination at the complex would likely be spread out over an extended period. As a result, the Company believes it is unlikely that any remediation costs allocable to it will be material in terms of expenditures made in any individual reporting period.

In addition to the matters described above, the Company is involved in various routine legal proceedings incidental to the conduct of its business. The Company does not believe that any of these routine legal proceedings will have a material adverse effect on its financial condition, results of operations or cash flows.

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Accumulated Other Comprehensive Income

9 Months Ended

Sep. 30, 2013

Equity [Abstract]

Accumulated Other Comprehensive Income

Accumulated Other Comprehensive Loss

Changes in accumulated other comprehensive income (loss) by component for the nine months ended September 30, 2013 were as follows:

	Benefits Liability, Net of Tax			Cumulative Foreign Currency Exchange			Net Unrealized Holding Gains on Investments, Net of Tax		Total
Balances at December 31, 2012	$	(16,351	)	$	5,511		$	—	$	(10,840	)
Other comprehensive (loss) income before    reclassifications	(601		)	(844		)	131		(1,314		)
Amounts reclassified from accumulated other    comprehensive loss	1,233			—			—		1,233
Net other comprehensive income (loss) for the period	632			(844		)	131		(81		)
Balances at September 30, 2013	$	(15,719	)	$	4,667		$	131	$	(10,921	)

The following table provides the details of the amounts reclassified from accumulated other comprehensive income (loss) into net income in the consolidated statements of operations for the three and nine months ended September 30, 2013:

Details about Accumulated Other Comprehensive    Income (Loss) Components	Location of Reclassification (Income (Expense)) in Consolidated Statements of Operations	Three Months Ended September 30, 2013			Nine Months Ended September 30, 2013
Amortization of pension and other post-retirement items
Prior service costs	(1)	$	(95	)	$	(286	)
Net loss	(1)	(600		)	(1,718		)
		(695		)	(2,004		)
	Provision for income taxes	267			771
Total reclassifications for the period		$	(428	)	$	(1,233	)

_____________

(1) These accumulated other comprehensive loss components are included in the computation of net periodic benefit cost. For additional information, please read Note 8 (Employee Benefits) to the financial statements included in the 2012 Form 10-K.

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Document and Entity Information	9 Months Ended
	Sep. 30, 2013	Nov. 01, 2013
Document Documentand Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2013
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q3
Trading Symbol	WLK
Entity Registrant Name	WESTLAKE CHEMICAL CORP
Entity Central Index Key	0001262823
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		66,770,803

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Acquisitions

9 Months Ended

Sep. 30, 2013

Business Combinations [Abstract]

Acquisitions

Acquisitions

On May 1, 2013, the Company acquired assets comprising CertainTeed Corporation's Pipe and Foundation Group ("PFG") business and accounted for the asset acquisition as a business combination. The PFG acquisition includes the PVC pipe, fittings, profiles and foundation business and associated facilities in Lodi, California and McPherson, Kansas with production capacity of approximately 150 million pounds per year. The Company also acquired technologies and intellectual property for the production of a number of specialized products, including Certa-Lok® restrained joint pipe and Yelomine™ branded products for a variety of end-market applications. The Company's management believes that this acquisition will enhance the Company's building products portfolio by adding new specialty product lines and supporting technology.

The closing date purchase price of $178,309 was paid with available cash on hand. This amount is subject to a post-closing working capital adjustment. The acquisition is being accounted for under the acquisition method of accounting. The assets acquired and liabilities assumed and the results of operations of this acquired business are included in the Vinyls segment. The revenue and earnings of the PFG business included in the consolidated statement of operations since the acquisition date have not been presented separately as they are not material to the Company's consolidated statements of operations for the three and nine months ended September 30, 2013. The pro forma impact of this business combination has not been presented as it is not material to the Company's consolidated statements of operations for the three and nine months ended September 30, 2013 and 2012.

For the nine months ended September 30, 2013, the Company recognized $1,124 of acquisition-related costs. These costs are included in selling, general and administrative expenses in the consolidated statement of operations for the nine months ended September 30, 2013.

The following table summarizes the consideration transferred and the estimated fair value of identified assets acquired and liabilities assumed at the date of acquisition. The final determination of fair value for certain assets and liabilities will be completed as soon as the information necessary to complete the analysis is obtained. These amounts will be finalized as soon as possible, but no later than one year from the acquisition date.

Fair value of consideration transferred:
Cash	$	178,309
Preliminary allocation of consideration transferred to net assets acquired:
Accounts receivable (1)	$	17,695
Inventories	25,948
Property, plant and equipment	31,261
Intangible assets:
Customer relationships (weighted average life of 15 years)	57,600
Trademarks	5,200
Developed technology (weighted average life of 15 years)	18,900
Other intangibles (weighted average life of two years)	300
Current liabilities	(10,595		)
Other liabilities	(26		)
Total identifiable net assets	146,283
Goodwill (2)	32,026
Consideration transferred	$	178,309

_____________

(1) The fair value of accounts receivable acquired is $17,695, with the gross contractual amount being $17,772. The Company expects $77 to be uncollectible.

(2) The goodwill recognized is primarily attributable to synergies from the Company's vinyls integration strategy expected to arise from the Company's PFG acquisition, as well as intangible assets that do not qualify for separate recognition. The goodwill is expected to be deductible for income tax purposes. The Company has not yet completed the process of assigning the goodwill to its reporting units.

Supplemental Noncash Investing Cash Flow Information

In conjunction with the acquisition, liabilities assumed consist of the following:

Fair value of assets acquired	$	188,930
Cash paid	(178,309		)
Liabilities assumed	$	10,621

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Earnings per Share (Reconciliation of Denominator for Basic and Diluted Earnings Per Share) (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Earnings Per Share [Abstract]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	68,662	168,362	57,759	293,062
Basic	66,628,747	66,311,958	66,628,027	66,240,225
Plus incremental shares from: Assumed exercise of options	276,807	344,802	275,352	381,295
Weighted average common shares-diluted	66,905,554	66,656,760	66,903,379	66,621,520
Earnings per share: Basic	$ 2.55	$ 1.30	$ 6.57	$ 4.36
Earnings per share: Diluted	$ 2.54	$ 1.30	$ 6.54	$ 4.33

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Earnings per Share (Schedule of Net Income Attributable to Common Stockholders) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Earnings Per Share [Abstract]
Net income	$ 170,290	$ 86,964	$ 439,453	$ 290,278
Less: Net income attributable to participating securities	(587)	(452)	(1,691)	(1,682)
Net income attributable to common shareholders	$ 169,703	$ 86,512	$ 437,762	$ 288,596