General— Under our McDermott International, Inc. 2016 Long-Term Incentive Plan, we can award stock-based compensation to members of our Board of Directors, employees and consultants in a number of forms, including incentive and non-qualified stock options, restricted stock, restricted stock units (“RSUs”), and performance shares or units. In addition, under the Chicago Bridge & Iron 2008 Long-Term Incentive Plan and The Shaw Group Inc. 2008 Omnibus Incentive Plan (the “Shaw Plan”), we can award similar forms of stock-based compensation, as well as stock appreciation rights under the Shaw Plan. As of December 31, 2018, there were 5 million shares remaining available for future awards under these equity-based compensation plans.

Our plans are administered by the Compensation Committee of our Board of Directors, which selects those employees eligible to receive awards and determines the number of shares or stock options subject to each award, as well as the terms, conditions, performance measures and other provisions of the award.

Combination―As of the Combination Date, unvested and unexercised stock-settled equity-based awards (which included approximately 2.1 million RSUs and stock options and stock appreciation rights with respect to 0.1 million shares) relating to shares of CB&I’s common stock were cancelled and converted into comparable McDermott stock-settled awards with generally the same terms and conditions as those prior to the Combination Date. The restricted stock units generally vest over a period ranging from three to four years from the original grant date.

Equity-Based Compensation Expense―Equity instruments are measured at fair value on the grant date. Stock-based compensation expense is generally recognized on a straight-line basis over the requisite service periods of the awards. Compensation expense is based on awards we expect to ultimately vest. We recognize forfeitures as they occur, rather than estimating expected forfeitures.

	2018 ⁽¹⁾		2017		2016
	(In millions)
RSUs	$	44	$	15	$	16
Liability awards		8		8		7
Total	$	52	$	23	$	23

The components of the total gross unrecognized estimated compensation expense for equity awards and their expected remaining weighted-average periods for expense recognition are as follows:

Amount

(In millions)

Weighted-Average Period (years)

Restricted stock and RSUs ⁽¹⁾

1.7

There were no stock options granted in 2018, 2017 or 2016. CB&I’s stock options that were cancelled and converted in connection with the Combination were not material.

Stock options exercised during 2018 were not material, and there were no stock options exercised during 2017 or 2016.

As of December 31, 2018, we had outstanding stock options to purchase 0.5 million shares with a weighted-average exercise price per share of approximately $37. All outstanding stock options vested prior to December 31, 2018.

Had all option holders exercised their options on December 31, 2018, the aggregate intrinsic value of the options would have been negative, as their exercise price was higher than closing price of our common stock on December 31, 2018.

	Number of Shares			Weighted-Average Grant Date Fair Value
Outstanding as of December 31, 2017		2		$	14.27
Granted ⁽¹⁾		3			20.36
Vested		(2	)		16.55
Outstanding as of December 31, 2018		3		$	19.39

There were no tax benefits realized related to RSUs and RSAs that lapsed or vested during 2018, 2017 and 2016.

Performance units granted in 2016 and 2017 (which have since been converted to RSUs) and the performance units granted in 2018 totaling 0.4 million, 0.2 million and 0.4 million shares, respectively, are classified as liability awards. These awards are valued at the market price of the underlying stock on the date of payment. Compensation cost for liability awards is re-measured at the end of each reporting period and is recognized as an expense over the applicable service period.

In March 2018, we settled in cash 0.5 million performance units, which were granted in March 2015.

As of December 31, 2018, the unrecognized compensation cost related to liability awards was $3 million, calculated based on the December 31, 2018 fair value of these awards, and is expected to be recognized over a weighted average period of two years.