Second-quarter net income rose to $201 million or $3.67 per share, from $126 million or $3.57 per share a year earlier.

Excluding costs related to CME's 2007 purchase of Chicago Board of Trade and other special items, income rose to $215 million or $3.93 per share, from $194 million or $3.52 per share a year before.

On that basis, analysts on average had expected earnings of $3.85 per share.

Revenue rose 71 percent to $563 million, matching analysts' expectations.

CME's quarterly futures and options trading volume was previously reported as up 7 percent from 2007, slower growth than the giant Chicago-based exchange has seen in recent years.

Turnover in interest rate contracts, CME's largest product line, slipped 3 percent in the second quarter from a year earlier as the global credit crunch forced some market participants to "deleverage," or reduce risky positions.

"We have seen record quarterly volumes in our foreign exchange and commodities product lines, and view current market conditions for interest rates as a cyclical slowdown rather than a long-term issue," CME Chairman Terry Duffy said in a statement.

The shift in trading mix away from interest rate contracts helped boost CME's average rate per contract, a key measure of margins, to 64.8 cents from 63 cents in the first quarter and 63.9 cents in last year's second quarter.

CME's operating margin was 62 percent against 59 percent for the same period in 2007.

CME said 2008 operating expenses should be closer to the bottom end of its previously-stated $855 million to $870 million estimate.

(Reporting by Ros Krasny)