Earnings (Loss) Per Share

We calculate basic earnings (loss) per share by dividing our net earnings (loss) available to common shareholders by our weighted-average shares outstanding at the end of the period. The calculation for diluted earnings (loss) per share adjusts the weighted average shares outstanding for our dilutive unvested shares and stock units using the treasury stock method and for our convertible notes using the if-converted method. Our calculations for basic and dilutive earnings (loss) per share for the years ended December 31, 2017, 2016, and 2015 are as follows:



(dollars in millions, except per share data, shares and stock units in thousands)	2017			2016		2015
Basic and dilutive net income (loss) available to common shareholders	$	(10.8	)	$	21.5	$	0.7

Basic weighted average shares outstanding	32,685			32,416		31,736
Effect of dilutive securities:
Unvested shares and stock units^(b)	—			624		616
Series B Notes	—			—		240
Dilutive weighted average shares outstanding	32,685			33,040		32,592

Basic earnings (loss) per share^(a)	$	(0.33	)	$	0.66	$	0.02
Diluted earnings (loss) per share^(a)	$	(0.33	)	$	0.65	$	0.02

^(a) Earnings (loss) per share is based on unrounded figures and not the rounded figures presented.

^(b)Includes unvested shares of Common Stock, unvested stock units, and vested stock units for which the underlying Common Stock has not been distributed.

Given our net loss position for the year ended December 31, 2017, there are no dilutive securities for this period.

Our anti-dilutive securities for the years ended December 31 are as follows:

^(a)Includes unvested shares of Common Stock, unvested stock units, and vested stock units for which the underlying Common Stock has not been distributed.

(shares and stock units in thousands)

Anti-dilutive unvested shares, options, and stock units^(a)