Note 11. Stock‑Based Compensation Plans

We grant stock‑based compensation to our employees and directors. At December 31, 2018, an aggregate of 1,475,547 shares were authorized for future grant under our various stock‑based compensation plans, including stock options, restricted stock units and stock awards. Awards that expire or are canceled without delivery of shares generally become available for issuance under the plans. As stock options are exercised and restricted stock units vest, we issue new shares of Reliance common stock.

Stock Options

Stock option activity under all the plans is as follows:


				Weighted Average
				Remaining	Aggregate
	Option	Weighted Average		Contractual Term	Intrinsic Value
Stock Options	Shares	Exercise Price		(in years)	(in millions)
Outstanding at January 1, 2016	934,325	$	50.26
Exercised	(753,645)		49.70
Outstanding at December 31, 2016	180,680		52.61
Exercised	(98,405)		52.41
Expired or forfeited	(7,000)		58.68
Outstanding at December 31, 2017	75,275		52.30
Exercised	(48,275)		57.91
Expired or forfeited	(1,000)		55.73
Outstanding at December 31, 2018	26,000	$	41.76	0.9	$	0.8
Exercisable at December 31, 2018	26,000	$	41.76	0.9	$	0.8

All stock options outstanding at December 31, 2018 were granted to our non‑employee directors and had one-year vesting periods and ten-year terms.

There were no unvested stock options at December 31, 2018 and 2017.

Proceeds from stock options exercised under all stock option plans in 2018, 2017 and 2016 were $2.8 million, $5.2 million and $37.5 million, respectively. The total intrinsic values of all options exercised in 2018, 2017 and 2016 were $1.6 million, $2.8 million and $16.3 million, respectively.

The following tabulation summarizes certain information concerning outstanding and exercisable options as of December 31, 2018:


		Weighted Average
	Outstanding and	Remaining	Weighted Average
Range of	Exercisable at	Contractual Life	Exercise Price
Exercise Price	December 31, 2018	in Years	Per Share
$38	12,000	0.4	$	38.00
$44 - $45	14,000	1.4		44.99
$38 - $45	26,000	0.9	$	41.76

Restricted Stock

In 2018, 2017 and 2016, we granted 474,715, 446,525 and 512,895, respectively, restricted stock units (“RSUs”) to key employees pursuant to the Amended and Restated Stock Option and Restricted Stock Plan. Each RSU consists of the right to receive one share of our common stock and dividend equivalent rights, subject to forfeiture, equal to the accrued cash or stock dividends where the record date for such dividends is after the grant date but before the shares vest. Additionally, each 2018, 2017 and 2016 RSU granted has a service-based condition and cliff vests at December 1, 2020, December 1, 2019 and December 31, 2018, respectively, if the recipient is an employee on those dates. In addition to the service-based condition, 178,970, 169,009 and 190,175 of the RSUs granted in 2018, 2017 and 2016, respectively, also have performance goals and vest only upon the satisfaction of the service-based condition and certain three-year performance targets. The fair value of the 2018, 2017 and 2016 RSUs granted was $84.26 per share, $79.60 per share and $69.16 per share, respectively, determined based on the closing price of our common stock on the grant date.

In 2018, 2017 and 2016, 13,880, 18,120 and 11,851 stock awards, respectively, were granted to the non‑employee members of the Board of Directors pursuant to the Directors Equity Plan. The fair value of the stock awards granted in 2018, 2017 and 2016, was $93.65 per share, $71.73 per share and $70.88 per share, respectively, determined based on the closing price of our common stock on the grant date. The awards include dividend rights and vest immediately upon grant.

In 2018, 2017 and 2016, we made payments of $12.3 million, $9.3 million and $6.4 million, respectively, to tax authorities on our employees’ behalf for shares withheld related to net share settlements. These payments are reflected in the Stock-based compensation caption of the statement of equity.

A summary of the status of our unvested service-based and performance-based RSUs as of December 31, 2018 and changes during the year then ended is as follows:



		Weighted Average
		Grant Date Fair
Unvested RSUs	Shares	Value Per RSU
Unvested at January 1, 2018	924,575	$	74.09
Granted	474,715		84.26
Vested	(484,858)		69.32
Canceled or forfeited	(24,602)		76.72
Unvested at December 31, 2018	889,830	$	82.05

Unrecognized Compensation Cost and Tax Benefits

As of December 31, 2018, there was $48.8 million of total unrecognized compensation cost related to unvested stock‑based compensation awards granted under all stock‑based compensation plans. That cost is expected to be recognized over a weighted average period of 1.35 years.

The tax benefit realized from our stock‑based compensation plans in 2018, 2017 and 2016 was $4.9 million, $8.4 million and $14.3 million, respectively.