Stockholders' Equity and Earnings Per Common Share

12 Months Ended

Dec. 31, 2017

Stockholders' Equity and Earnings Per Common Share [Abstract]

Earnings Per Common Share

Net income per common share is determined as follows:



	Year Ended December 31
	2017		2016		2015
	(in millions of dollars, except share data)
Numerator
Net Income	$	994.2	$	931.4	$	867.1

Denominator (000s)
Weighted Average Common Shares - Basic	226,492.4		235,445.7		246,986.7
Dilution for Assumed Exercises of Stock Options and Nonvested Stock Awards	842.8		533.5		868.0
Weighted Average Common Shares - Assuming Dilution	227,335.2		235,979.2		247,854.7

Net Income Per Common Share
Basic	$	4.39	$	3.96	$	3.51
Assuming Dilution	$	4.37	$	3.95	$	3.50

We use the treasury stock method to account for the effect of outstanding stock options, nonvested restricted stock units, and nonvested performance share units on the computation of diluted earnings per share. Under this method, these potential common shares will each have a dilutive effect, as individually measured, when the average market price of Unum Group common stock during the period exceeds the exercise price of the stock options and the grant price of the nonvested restricted stock units and the nonvested performance share units. The outstanding stock options have exercise prices ranging from $20.78 to $26.29; the nonvested restricted stock units have grant prices ranging from $27.85 to $53.94; and the nonvested performance share units have grant prices ranging from $27.85 to $49.86. See Note 11.

In computing earnings per share assuming dilution, only potential common shares that are dilutive (those that reduce earnings per share) are included. Potential common shares not included in the computation of diluted earnings per share because the impact would be antidilutive, based on then current market prices, approximated a de minimis amount for the year ended December 31, 2017, and 0.4 million, and 0.3 million for the years ended December 31, 2016, and 2015, respectively.

Stockholders' Equity Disclosure

Common Stock

Our board of directors has authorized the repurchase of Unum Group's common stock under the following repurchase programs:



	Share Repurchase Program Authorized During
	May 2017		May 2016		May 2015
	(in millions of dollars)
Authorized Repurchase Amount	$	750.0	$	750.0	$	750.0
Remaining Repurchase Amount at Year End 2017	$	512.8	$	—	$	—

The May 2017 share repurchase program has an expiration date of November 25, 2018.

Common stock repurchases, which are accounted for using the cost method and classified as treasury stock until otherwise retired, were as follows:



	Year Ended December 31
	2017		2016		2015
	(in millions)
Shares Repurchased	8.2		11.9		12.3
Cost of Shares Repurchased (1)	$	400.4	$	403.3	$	426.7

(1) Includes commissions of $0.3 million, $0.2 million, and $0.3 million for the years ended December 31, 2017, 2016, and 2015, respectively.

Preferred Stock

Unum Group has 25.0 million shares of preferred stock authorized with a par value of $0.10 per share. No preferred stock has been issued to date.