14. Stock-Based Compensation

In May 2018, the Company adopted the NBT Bancorp Inc. 2018 Omnibus Incentive Plan (the “Stock Plan”) which replaced the 2008 Omnibus Incentive Plan which automatically expired in April 2018. Under the terms of the Stock Plan, equity-based awards are granted to directors and employees to increase their direct proprietary interest in the operations and success of the Company. The Stock Plan assumed all prior equity-based incentive plans and any new equity-based awards are granted under the terms of the Stock Plan. Restricted shares granted under the Plan typically vest after five years for employees and three years for non-employee directors. Restricted stock units granted under the Stock Plan may have different terms and conditions. Performance shares and units granted under the Stock Plan for executives may have different terms and conditions. Since 2011, the Company primarily grants restricted stock unit awards. Stock option grants since that time were reloads of existing grants which terminate ten years from the date of the grant. Under terms of the Stock Plan, stock options are granted to purchase shares of the Company’s common stock at a price equal to the fair market value of the common stock on the date of the grant. Shares issued as a result of stock option exercises and vesting of restricted shares and stock unit awards are funded from the Company’s treasury stock.

The Company has outstanding restricted stock granted from various plans at December 31, 2018. The Company recognized $3.9 million, $3.5 million and $4.2 million in stock-based compensation expense related to these stock awards for the years ended December 31, 2018, 2017 and 2016, respectively. Tax benefits recognized with respect to restricted stock awards and stock units were $1.2 million, $2.5 million and $2.9 million for the years ended December 31, 2018, 2017 and 2016, respectively. Unrecognized compensation cost related to restricted stock units totaled $5.4 million at December 31, 2018 and will be recognized over 2.0 years on a weighted average basis. Shares issued are funded from the Company’s treasury stock. The following table summarizes information for unvested restricted stock units outstanding as of December 31, 2018:

	Number of Shares			Weighted-Average Grant Date Fair Value
Unvested at January 1, 2018		534,738		$	25.77
Forfeited		(5,999	)		29.56
Vested		(123,642	)		23.44
Granted		140,957			33.80
Unvested at December 31, 2018		546,054		$	28.39

The following table summarizes information concerning stock options outstanding:

(In thousands, except share and per share data)	Number of Shares			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (in Years)		Aggregate Intrinsic Value
Outstanding at January 1, 2018		112,030		$	22.88
Exercised		(44,105	)		22.65
Expired		(1,025	)		20.36
Outstanding at December 31, 2018		66,900		$	23.07		1.78	$	779,933

Exercisable at December 31, 2018		65,400		$	22.66		1.64	$	779,933

Expected to Vest		1,500		$	40.63		8.12	$	-

Total stock-based compensation expense for stock option awards totaled $11 thousand, $18 thousand and $235 thousand for the years ended December 31, 2018, 2017 and 2016, respectively. Cash proceeds, tax benefits and intrinsic value related to total stock options exercised is as follows:

	Years ended December 31,
(In thousands)	2018		2017		2016
Proceeds from stock options exercised	$	999	$	3,083	$	8,398
Tax benefits related to stock options exercised		173		650		1,223
Intrinsic value of stock options exercised		692		1,699		3,143
Fair value of shares vested during the year		16		329		105

The Company has 1,183,984 securities remaining available to be granted as part of the Plan at December 31, 2018.