Note 5 — Stock Options

On April 5, 2012, the Board of Directors adopted the 2012 International Bancshares Corporation Stock Option Plan (the “2012 Plan”). There are 800,000 shares of common stock available for stock option grants under the 2012 Plan, which may be qualified incentive stock options (“ISOs”) or non-qualified stock options. Options granted may be exercisable for a period of up to 10 years from the date of grant, excluding ISOs granted to 10% shareholders, which may be exercisable for a period of up to only five years. As of March 31, 2018, 232,200 shares were available for future grants under the 2012 Plan. No awards were made under the 2012 Plan during the three months ended March 31, 2018.

A summary of option activity under the stock option plan for the three months ended March 31, 2018 is as follows:


				Weighted
		Weighted		average
		average		remaining	Aggregate
	Number of	exercise		contractual	intrinsic
	options	price		term (years)	value ($)
					(in Thousands)
Options outstanding at December 31, 2017	668,166	$	20.41
Plus: Options granted	—		—
Less:
Options exercised	25,013		17.60
Options expired	—		—
Options forfeited	15,800		18.58
Options outstanding at March 31, 2018	627,353		20.57	5.36	$	11,499

Options fully vested and exercisable at March 31, 2018	344,435	$	19.47	4.69	$	6,692

Stock-based compensation expense included in the consolidated statements of income for the three months ended March 31, 2018 and three months ended March 31, 2017 was approximately $184,800 and $268,000, respectively. As of March 31, 2018, there was approximately $1,233,600 of total unrecognized stock-based compensation cost related to non-vested options granted under the Company plans that will be recognized over a weighted average period of 1.3 years.