13. Earnings per share of QTS Realty Trust, Inc.

Basic income per share is calculated by dividing the net income attributable to common shares by the weighted average number of common shares outstanding during the period. Diluted income per share adjusts basic income per share for the effects of potentially dilutive common shares. Unvested restricted stock awards and the Company’s forward sale contract described in Note 10 contain non-forfeitable rights to dividends and thus are participating securities and are included in the computation of basic earnings per share pursuant to the two-class method for all periods presented. The two-class method is an earnings allocation formula that treats a participating security as having rights to undistributed earnings that would otherwise have been available to common stockholders. Accordingly, service-based restricted stock awards and the forward sale contract were included in the calculation of basic earnings per share using the two-class method for all periods presented to the extent outstanding during the period.

The computation of basic and diluted net income per share is as follows (in thousands, except per share data, and unaudited):


	Three Months Ended
	March 31,
	2019		2018
Numerator:
Net income (loss)	$	21,148	$	(252)
Loss (income) attributable to noncontrolling interests		(1,590)		29
Preferred stock dividends		(7,045)		(328)
Earnings attributable to participating securities		(1,935)		(258)
Net income (loss) available to common stockholders after allocation of participating securities	$	10,578	$	(809)
Denominator:
Weighted average shares outstanding - basic		51,948		50,279
Effect of Class O units, TSR units and options to purchase Class A common stock on an "as if" converted basis		347		—
Weighted average shares outstanding - diluted		52,295		50,279

Basic net income (loss) per share	$	0.20	$	(0.02)

Diluted net income (loss) per share	$	0.20	$	(0.02)

Note: The table above does not include Class A partnership units of 6.7 million and 6.6 million for the three months ended March 31, 2019, and 2018, respectively, as their inclusion would have been antidilutive. Also does not include 0.5 million reflecting the effects of Class O units and options to purchase common stock on an "as if" converted basis for the three months ended March 31, 2018, and 6.7 million reflecting the effects of Series B Convertible preferred stock on an “as if” converted basis for the three months ended March 31, 2019, as their respective inclusion would have also been antidilutive.