12. STOCK-BASED COMPENSATION

On May 17, 2011, our shareholders approved the Axiall Corporation 2011 Equity and Performance Incentive Plan (the "2011 Plan"). In January 2013, our shareholders approved an amendment to the 2011 Plan to increase the number of shares available under the plan by 1.8 million shares. Under the 2011 Plan as it existed at March 31, 2013, we were authorized to grant various stock-based compensation awards for up to 3.6 million shares of our common stock to officers, employees and non-employee directors, among others. We have granted various types of share-based payment awards to participants, including restricted stock unit awards and stock option grants. Our policy is to issue new shares upon the exercise of stock options and the vesting of restricted stock units. As of March 31, 2013, there were approximately 3.0 million shares available for future grant to participants under our 2011 Plan. In connection with our adoption and shareholder approval of the 2011 Plan, we agreed to not grant additional stock-based compensation awards under our previously existing equity compensation plans.

Total after-tax share-based compensation cost by type of program was as follows:

	Three Months Ended March 31

*(In millions)*	2013			2012
Restricted stock units expense	$	1.6		$	1.1
Stock options expense		0.3			-

Before-tax share-based compensation expense		1.9			1.1
Income tax benefit		(0.6	)		(0.3	)

After-tax share-based compensation expense	$	1.3		$	0.8

The amount of share-based compensation cost capitalized in the periods presented was not material during the three months ended March 31, 2013.

As of March 31, 2013 and 2012, we had approximately $12.0 million and $5.1 million, respectively, of total unrecognized compensation costs related to nonvested share-based compensation, which we will record in our Condensed Consolidated Statements of Operations over a weighted average recognition period of approximately two years. The total fair value of shares vested during the three months ended March 31, 2013 and 2012 was approximately $0.1 million and $0.4 million, respectively.

Stock Options. A summary of stock option activity under all plans as of and for the three months ended March 31, 2013 is as follows:

			Weighted Average Remaining Contractual Terms (Years)	Weighted Average Exercise Price		Aggregate Intrinsic Value *(In millions)*

Outstanding on January 1, 2013	125,564			$	292.76
Granted	188,330				33.72
Exercised	(1,832	)			21.25
Expired	(5,301	)			508.64

Outstanding on March 31, 2013	306,761		7.0 years	$	131.62	$	7.3

Exercisable as of March 31, 2013	118,431		4.6 years	$	287.30	$	1.9
Vested or expected to vest as of March 31, 2013	174,030		8.4 years	$	33.72	$	5.0

During the three months ended March 31, 2013, we granted options to purchase shares primarily to replace unvested awards of former employees of the Merged Business who became Axiall employees, in accordance with the Merger Agreement. In 2012, we granted no options to purchase shares. The fair value of stock options when granted has been estimated as of the date of grant using the Black-Scholes option pricing model. Option exercise prices are equal to the closing price of our common stock on the date of grant. Options generally vest over a three year period from the date of grant and expire no more than ten years after the date of grant. The intrinsic value is calculated as the difference between the market value at period end and the exercise price of the shares. There were no significant options exercised during the three months ended March 31, 2012.

Restricted Stock Units. A summary of restricted stock unit activity under all plans as of and for the three months ended March 31, 2013 is as follows:

			Weighted Average Remaining Contractual Terms (Years)	Weighted Average Grant Date Fair Value		Aggregate Intrinsic Value *(In millions)*

Outstanding on January 1, 2013	716,907			$	27.86
Granted	89,637				38.26
Vested and released	(3,975	)			17.62
Forfeited	(2,338	)			26.62

Outstanding on March 31, 2013	800,231		1.3 years	$	29.08	$	49.7

Vested or expected to vest as of March 31, 2013	769,748		1.3 years	$	29.18	$	47.8

During the three months ended March 31, 2013, we granted restricted stock units to purchase shares primarily to replace unvested awards of former employees of the Merged Business who became Axiall employees, in accordance with the Merger Agreement. The restricted stock units normally vest over a one- or three-year period. The weighted average grant date fair value per share of restricted stock units is based on the stock price as of the date of grant or, in the case of the performance restricted stock units ("PRSUs"), the fair value, estimated using a Monte Carlo simulation model. The total intrinsic value of restricted stock units that vested during the three months ended March 31, 2013 and 2012 was $0.2 million and $0.1 million, respectively.

In May 2012, we granted PRSUs, which are a form of restricted stock units in which the number of shares ultimately earned depends on our stock price performance measured against specified performance targets. Following each vesting period, the number of PRSUs subject to award is determined by multiplying the target award by a percentage ranging from 0 percent to 150 percent. The percentage is based on predetermined performance metrics related to our stock price for the stated period. The PRSUs are included with all restricted stock units in all calculations.