Stock exchange operator NYSE Euronext reported a near-20% drop in net profit for the second quarter, due partly to higher costs tied to its planned merger with Germany's Deutsche Börse and the absence of a tax gain recorded in the year-earlier period.

Net profit for the second quarter was $154m, or $0.59 a share, compared with $184m a year earlier, when the Big Board operator benefited from a $54 million pretax gain from divestitures.