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. Our calculations for basic and dilutive earnings (loss) per share for the years ended December 31, 2018, 2017, and 2016 are as follows:



(dollars in millions, except per share data, shares and stock units in thousands)	2018		2017			2016
Basic and dilutive net income (loss) available to common shareholders	$	20.2	$	(10.8	)	$	21.5

Basic weighted average shares outstanding	32,983		32,685			32,416
Effect of dilutive securities:
Unvested shares and stock units^(a)	876		—			624
Dilutive weighted average shares outstanding	33,859		32,685			33,040

Basic earnings (loss) per share^(b)	$	0.61	$	(0.33	)	$	0.66
Diluted earnings (loss) per share^(b)	$	0.60	$	(0.33	)	$	0.65

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

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

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:

(shares in thousands)

Anti-dilutive unvested shares and options