CHICAGO, July 31 (Reuters) - CME Group Inc, the world's largest futures market operator, on Thursday reported lower-than-expected second-quarter earnings due to weak trading volumes.
Net profit fell to $263.8 million, or 79 cents a share, from $311.2 million, or 93 cents a share, a year earlier.
Excluding special items, earnings were 77 cents a share, below analysts' expectations of 79 cents, according to Thomson Reuters I/B/E/S.
Revenue dropped to $731.6 million from $816.1 million.
The average daily trading volume at CME, owner of the Chicago Board of Trade and Chicago Mercantile Exchange, slid 12 percent. The total average rate per contract was 74.9 cents, up slightly from a year earlier.
(Reporting by Tom Polansek; Editing by Lisa Von Ahn)