Common Stock

In July 2012, February 2011, and May 2010, our board of directors authorized the repurchase of up to $750.0 million, $1.0 billion, and $500.0 million, respectively, of Unum Group's common stock. At December 31, 2012, no amounts were remaining for the purchase of shares under either the February 2011 or May 2010 repurchase program. The July 2012 share repurchase program has an expiration date of January 2014, and the dollar value of shares remaining under this program was $550.0 million at December 31, 2012.

Common stock repurchases were classified as follows in our consolidated statements of stockholders' equity:



	Year Ended December 31
	2012			2011			2010
	Shares	Cost (1)		Shares	Cost (1)		Shares	Cost (1)
	(in millions)
Treasury Stock	23.6	$	500.6	17.7	$	419.9	16.4	$	356.0
Retirement of Common Shares (2)	—	—		7.7	200.0		—	—
Total	23.6	$	500.6	25.4	619.9		16.4	356.0

(1) Includes commissions of $0.6 million, $0.3 million, and $0.3 million for the years ended December 31, 2012, 2011, and 2010, respectively.

(2) In February 2011, we repurchased 7.1 million shares, at a cost of $200.0 million, using an accelerated repurchase agreement with a financial counterparty. As part of this transaction, we simultaneously entered into a forward contract indexed to the price of Unum Group common stock, which subjected the transaction to a future price adjustment. Under the terms of the repurchase agreement, we were to receive, or be required to pay, a price adjustment based on the volume weighted average price of Unum Group common stock during the term of the agreement, less a discount. Any price adjustment payable to us was to be settled in shares of Unum Group common stock. Any price adjustment we would have been required to pay would have been settled in either cash or common stock at our option. The final price adjustment settlement occurred in March 2011, resulting in the delivery to us of 0.6 million additional shares.

Preferred Stock

Unum Group has 25,000,000 shares of preferred stock authorized with a par value of $0.10 per share. No preferred stock has been issued to date.

Earnings Per Common Share

Net income per common share is determined as follows:



	Year Ended December 31
	2012		2011		2010
	(in millions of dollars, except share data)
Numerator
Net Income	$	894.4	$	284.2	$	878.7

Denominator (000s)
Weighted Average Common Shares - Basic	281,355.9		302,399.8		325,839.0
Dilution for Assumed Exercises of Stock Options and Nonvested Stock Awards	400.9		1,171.2		1,382.1
Weighted Average Common Shares - Assuming Dilution	281,756.8		303,571.0		327,221.1

Net Income Per Common Share
Basic	$	3.18	$	0.94	$	2.70
Assuming Dilution	$	3.17	$	0.94	$	2.69

We use the treasury stock method to account for the effect of outstanding stock options and nonvested stock awards on the computation of dilutive 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/or the grant price of the nonvested stock awards. For further discussion of stock-based awards see Note 10.

The outstanding stock options have exercise prices ranging from $11.37 to $26.29, and the nonvested stock awards have grant prices ranging from $19.38 to $26.31.

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 dilutive earnings per share because their impact would be antidilutive, based on current market prices, approximated 2.5 million, 2.1 million, and 3.5 million shares of common stock for the years ended December 31, 2012, 2011, and 2010, respectively.