Historically, we have maintained various long-term incentive plans including employee stock options, restricted stock awards, restricted stock units (that settle in Tidewater common stock), phantom stock, and cash-based performance awards. As discussed in greater detail in Note (17) we filed voluntary petitions for Chapter 11 bankruptcy protection on May 17, 2017 to effectuate a restructuring pursuant to a Plan. As a result of the Restructuring, all of our outstanding equity and incentive programs (and all outstanding stock options and awards under those programs) were cancelled, except for unvested phantom stock awards held by non-officer employees and certain deferred stock units and deferred cash awards held by non-employee members of the predecessor board, each as discussed in greater detail below.

On the Effective Date, a new equity incentive plan, the Tidewater Inc. 2017 Stock Incentive Plan (the “2017 Plan”) became effective pursuant to the operation of the Plan. At the closing of the Business Combination, we assumed sponsorship of the GulfMark Management Incentive Plan (as assumed and amended effective as of the closing, the “Legacy GLF Plan”), and also assumed all outstanding, unvested restricted stock units and the remaining shares available under the Legacy GLF Plan, all of which were adjusted to reflect the Exchange Ratio, rounding the resulting number down to the nearest whole number of shares of Tidewater common stock.

As of December 31, 2019, the 2017 Plan and the Legacy GLF Plan are our only two active equity incentive plans and the only type of award outstanding under either plan is restricted stock units (RSUs) that settle in shares of Tidewater common stock.

The number of common stock shares reserved for issuance under the plans and the number of shares available for future grants are as follows:

Successor

Predecessor

Period from

Year

August 1, 2017

April 1, 2017

Ended

through

December 31, 2019

December 31, 2018

December 31, 2017

July 31, 2017

Shares of common stock reserved for issuance under the plans

3,973,228

3,048,877

—

Shares of common stock available for future grants

2,187,101

2,325,102

1,891,231

—

The Predecessor granted stock options to its directors and employees under several different stock incentive plans. We used the Black-Scholes option-pricing model to calculate the share-based compensation expense. No stock options have been granted since April 1, 2017. Outstanding stock options of 1,395,548 with a weighted average exercise price of $28.14 were cancelled prior to emergence from chapter 11 bankruptcy. We recorded stock option compensation expense of $1.6 million in the period from April 1, 2017 through July 31, 2017.

The Predecessor and Successor have granted restricted stock units (RSUs) to key employees, including officers and non-employee directors. We have generally awarded time-based units, where each unit represents the right to receive, at the end of a vesting period, one unrestricted share of Tidewater common stock with no exercise price. Prior to its merger with Tidewater, GulfMark awarded RSUs under its management incentive plan to certain officers and employees of GulfMark and, as noted previously, those awards were assumed and converted based on the Exchange Ratio. These RSUs and are included as granted awards in the table below.

We have also awarded performance-based RSUs, where each unit represents the right to receive, at the end of a vesting period, up to two shares of Tidewater common stock with no exercise price based on various operating and financial metrics. The fair value of the performance-based and time-based RSUs is based on the market price of our common stock on the date of grant. The restrictions on the time-based RSUs awarded to key employees lapse over a three year period from the date of the award. The restrictions on the time-based RSUs awarded to non-employee directors lapse over a one year period. Time-based RSUs require no goals to be achieved other than the passage of time and continued employment. The restrictions on the performance-based restricted stock units lapse if we meet specific targets as defined. During the restricted period, the RSUs may not be transferred or encumbered, but the recipient has the right to receive dividend equivalents on the restricted stock units, but there are no voting rights until the restricted stock units vest. If dividends are declared, dividend equivalents are accrued on performance-based restricted shares and ultimately paid only if the performance criteria are achieved. RSU compensation costs are recognized on a straight-line basis over the vesting period, and are net of forfeitures.

All outstanding unvested RSUs granted under the Predecessor incentive plans vested prior to emergence from chapter 11 bankruptcy. RSUs granted to officers and employees by the Successor under the 2017 Incentive Plan, subsequent to emergence from Chapter 11 bankruptcy, generally have a vesting period over three years in equal installments from the date of grant, except that (i) the RSUs granted to directors vest over one year and (ii) certain RSUs granted to our officers are performance based and vest on the third anniversary of the date of grant, based on our performance as measured.

	Weighted-average Grant-Date Fair Value		Time Based Units			Weight-average Grant Date Fair Value		Performance Based Units
Non-vested balance at March 31, 2017 (Predecessor)	$	54.48		183			—		—
Vested		54.48		(183	)		—		—
Non-vested balance at August 1, 2017 (Successor)		—		—			—		—
Granted		24.40		1,203,379			—		—
Cancelled/forfeited		24.15		(45,733	)		—		—
Non-vested balance at December 31, 2017 (Successor)		24.41		1,157,646			—		—
Granted		24.58		455,063			26.04		63,365
Vested		24.84		(503,677	)		—		—
Cancelled/forfeited		27.15		(27,948	)		—		—
Non-vested balance at December 31, 2018 (Successor)		24.21		1,081,084			26.04		63,365
Granted		23.44		186,143			24.50		101,143
Vested		24.45		(784,868	)		—		—
Cancelled/forfeited		24.70		(78,591	)		24.50		(70,694	)
Non-vested balance at December 31, 2019 (Successor)	$	23.32		403,768			25.54		93,814

Restrictions on 167,856 time-based units outstanding at December 31, 2019 will lapse during fiscal 2020.

Restricted stock unit compensation expense and grant date fair value are as follows:

Successor

Predecessor

Period from

Year

August 1, 2017

April 1, 2017

Ended

through

(In thousands)

December 31,

2019

December 31,

2018

December 31,

2017

July 31,

2017

Grant date fair value of restricted stock units vested

19,193

12,513

—

Restricted stock unit compensation expense

19,603

13,406

3,731

As of December 31, 2019, total unrecognized RSU compensation costs totaled approximately $6.3 million, or $5.0 million net of tax which will be recognized over a weighted average period of two years, compared to $22.6 million, $17.1 million net of tax, at December 31, 2018. No RSU compensation costs were capitalized as part of the costs of an asset. The amount of unrecognized RSU compensation costs will be affected by any future restricted stock unit grants and by the separation of an employee who has received RSUs that are unvested as of their separation date. There were no modifications to the RSUs during the year ended March 31, 2017, the nine months ended December 31, 2017 or the years ended December 31, 2018 and 2019. Forfeitures are recognized as an adjustment to compensation expense for all RSUs in the same period as the forfeitures occur.

The Predecessor provided a Phantom Stock Plan (PSP) to provide additional incentive compensation to key employees. Participants in the PSP had the right to receive the value of a share of common stock in cash at vesting. Participants had no voting or other rights as a shareholder. The phantom shares generally had a three year vesting period. As a result of the restructuring, on the Effective Date, (i) all phantom units held by officers were cancelled for no value and (ii) all outstanding phantom stock units held by non-officer employees were converted in accordance with the conversion ratio for common stock provided in the Plan. No new awards have been issued under the Phantom Stock Plan since April 1, 2016.

	Weighted-average Grant-Date Fair Value		Time Based Shares			Weighted-average Grant-Date Fair Value		Series A Warrants			Weighted-average Grant-Date Fair Value		Series B Warrants
Non-vested balance at March 31, 2017 (Predecessor)	$	9.74		946,150
Cancelled		9.70		(484,446	)
Forfeited		10.08		(16,866	)
Non-vested balance at July 31, 2017 (Predecessor)	$	9.77		444,838

Issuance of Successor phantom stock at August 1, 2017		308.19		14,160			1.00		22,963			0.98		24,824

Cancelled/forfeited		307.31		(634	)		1.00		(1,029	)		0.98		(1,112	)
Non-vested balance at December 31, 2017 (Successor)	$	308.24		13,526			1.00		21,934			0.98		23,712
Vested		360.14		(8,223	)		1.00		(13,009	)		0.98		(14,064	)
Cancelled		240.39		(786	)		1.00		(1,275	)		0.98		(1,379	)
Non-vested balance at December 31, 2018 (Successor)	$	226.50		4,517			1.00		7,650			2.94		8,269
Vested		226.50		(4,517	)		1.00		(7,650	)		2.94		(8,269	)
Non-vested balance at December 31, 2019 (Successor)	$	—		—			—		—			—		—

Phantom stock compensation expense and grant date fair value of phantom stock vested are as follows:

Successor

Predecessor

Period from

Year

August 1, 2017

April 1, 2017

Ended

through

(In thousands)

December 31,

2019

December 31,

2018

December 31,

2017

July 31,

2017

Grant date fair value of phantom stock vested

1,055

2,957

—

Phantom stock compensation expense

214

As of December 31, 2019 and 2018, total unrecognized phantom stock compensation costs amounted to zero and $0.03 million, respectively.

In previous years, we provided a Cash-based Performance Plan as additional incentive compensation to company officers. Approximately 7.7 million units, representing all outstanding plan units, at a weighted average grant date fair value of $1.16 were cancelled or forfeited during the four month period ended July 31, 2017. There are no outstanding cash-based performance units after July 31, 2017. There were no modifications to the cash-based performance plan units during the four month period ended July 31, 2017.

Cash-based performance unit compensation expense was a $2.0 million credit in the four months ended July 31, 2017.

We provided a Deferred Stock Unit Plan to our non-employee directors. Each member of the Predecessor board was deemed to have resigned from the board on the Effective Date which triggered payout status for all outstanding deferred stock units. All outstanding deferred stock units were paid to the participants. No new awards have been issued under the Deferred Stock Unit Plan since April 1, 2016. Approximately 351,000 units were distributed to the Board members during the four month period ended July 31, 2017. These units had a weighted average grant date fair value of $24.19.