Basic net (loss) income per share is computed by dividing net (loss) income by the weighted daily average number of shares of common stock outstanding during the period. Diluted net (loss) income per share is based upon the weighted daily average number of shares of common stock outstanding for the period plus dilutive potential common shares, including restricted stock units, using the treasury-stock method.

Basic and diluted net (loss) income per common share and a reconciliation of the weighted average basic common shares outstanding to the weighted average diluted common shares outstanding is as follows:

	Three Months Ended					Six Months Ended
(millions, except share and per share data) (unaudited)	June 30, 2020			June 30, 2019		June 30, 2020			June 30, 2019
Net (loss) income attributable to SP Plus Corporation	$	(39.1	)	$	15.2	$	(85.2	)	$	25.8
Basic weighted average common shares outstanding		20,972,057			22,382,139		21,062,495			22,445,825
Dilutive impact of share-based awards		—			150,074		—			154,282
Diluted weighted average common shares outstanding		20,972,057			22,532,213		21,062,495			22,600,107
Net (loss) income per common share
Basic	$	(1.86	)	$	0.68	$	(4.05	)	$	1.15
Diluted	$	(1.86	)	$	0.68	$	(4.05	)	$	1.14

During the three and six months ended June 30, 2020, common stock equivalents arising from 153,442 restricted stock units were considered anti-dilutive. For the three and six months ended June 30, 2020 and 2019, unvested performance share units were excluded from the computation of weighted average diluted common share outstanding because the number of shares ultimately issuable is contingent on the Company's performance goals, which were not achieved as of the reporting dates.

There are no additional securities that could dilute basic earnings per share in the future that were not included in the computation of diluted earnings per share, other than those disclosed.