effect of dilutive securities ( 2 ) 1.5 2.2 2.1 diluted weighted-average shares outstanding ( 3 ) 171.8 172.8 158.7 ( 1 ) the 2013 basic weighted-average shares outstanding was impacted by common stock issued during the ipo and the underwriters 2019 exercise in full of the overallotment option granted to them in connection with the ipo