CME Group Inc.'s (CME) second-quarter profit declined 17% due to a fall in revenue amid lower trading volumes.

Like its fellow exchanges, the world's largest futures market operator grappled with slower trading in the second quarter as more investors headed for the sidelines of stock and derivatives markets in the U.S. and Europe. Investor confidence is still key following the twin collapses of MF Global Holdings Ltd. (MFGLQ) and Peregrine Financial Group Inc., leaving holes in futures traders' accounts.

The exchange also faces competition from IntercontinentalExchange Inc. (ICE), which has launched an all-electronic version of CME's benchmark grain futures, pushing CME to lengthen its trading session. More pressing, trading volumes have declined for four quarters, including the second-quarter's drop, with contracts linked to interest rates under particular pressure this spring.

In the latest period, average daily trading volume was down 9% from a year earlier to 12.4 million contracts.

Chief Executive Phupinder Gill, who is presiding over his first quarterly report at the exchange, said CME "will take aggressive steps to build products and services that address evolving customer needs and expand our industry leading business."

CME reported earnings of $244.9 million, or 74 cents a share, as compared with $293.7 million, or 88 cents a share, a year earlier. Adjusted earnings were 89 cents a share. Revenue fell 5.1% to $795.9 million.

Analysts polled by Thomson Reuters expected a per-share profit of 82 cents on revenue of $796 million.

Operating margin declined to 59% from 63.8%.

Class A shares closed at $51.26 Wednesday and were inactive in recent premarket trading. The stock is down 11% over the past 12 months.