But the derivatives, futures and options exchange operator said that if the New York Mercantile Exchange's results were fully included from last year, the parent company's profit would have fallen 20 percent.

CME Group, based in Chicago, acquired New York Mercantile Exchange in August of 2008, so its full quarterly results from the year-ago period were not completely reflected in CME Group's data from that period.

Its shares slipped 36 cents to $307.66 in midday trading.

The company earned $202 million, or $3.04 per share in the third quarter, compared with a profit of $168.7 million, or $2.81 per share, during the same quarter last year.

Excluding $21 million in costs tied to an impairment charge on the company's investment in Imarex - a Norwegian-based freight and energy exchange and broker - and merger-related items, CME Group earned $223 million, or $3.35 per share in the third quarter.

Analysts polled by Thomson Reuters, on average, forecast earnings of $3.29 per share for the quarter. Analysts typically exclude special charges in their estimates.

Revenue fell to $650.4 million from $680.9 million a year ago. Revenue was down 17 percent if the Mercantile Exchange's full third-quarter results from 2008 are included.

Trading volume declined again in the third quarter. Average daily volume fell to 10.1 million contracts traded from 13.1 million traded during the same quarter last year.

A decline in interest rate contracts again drove trading volume lower. With interest rates at historic lows and the Federal Reserve Board indicating it plans to keep key rates low in the near-term, interest rate-related futures contracts have not been as heavily traded.

Not even higher trading fees could offset the drop in trading volume. CME Group's average rate per contract increased to 83.4 cents from 79 cents.

A service of YellowBrix, Inc.