Bolstered by a tax benefit and expanding business, CME Group Inc. announced higher profits for the first quarter of 2011, beating Wall Street expectations Wednesday.

The Chicago-based futures exchange operator reported net income of $456.6 million, or $6.81 per diluted share, for the quarter ended March 31, a 90 percent increase from $240.2 million, or $3.62 per diluted share, in the year-earlier period.

Analysts surveyed by Zacks Investment Research were expecting diluted earnings per share of $4.18, far below actual results.

A $164.1 million benefit associated with a better-than-expected tax rate played a major role in boosting earnings. Without the tax credit, net income for the quarter would have been $292.2 million, or $4.36 per diluted share, much closer to analyst estimates.

The company also benefitted from higher trading activity, which contributed to record revenue of $831.6 million, up 20 percent from the first quarter last year when revenue was 693.2 million. Average daily volume rose to 13.8 million traded contracts, compared with 11.5 million in the prior-year quarter.

In a release, Executive Chairman Terry Duffy said exchange-traded and over-the-counter agricultural, energy and metal products hit record quarterly volume highs. The lift was driven by robust global demand for commodities.

Despite the strong revenue showing, analyst Patrick O’Shaughnessy of Raymond James Financial Inc. is keeping an eye on CME Group’s expenses, which have risen each quarter for the last year.

“Operating expenses once again came in higher than expected, thus offsetting some of the top-line growth,” O’Shaughnessy said in a research note.

In a conference call, the company’s chief financial officer, James Parisi, said CME Group is continuing to invest in its core business of financial products and commodities.

CEO Craig Donohue discussed the company’s global growth strategy, which includes this month’s launch of a north-to-south order routing system with exchange partner Bolsa Mexicana de Valores and next week’s launch of CME Clearing Europe, which will begin with more than 150 over-the-counter commodity products.

Donahue also explained why CME Group has avoided the merger frenzy surrounding the potential buyout of NYSE Euronext by either Deutsche Börse AG or Nasdaq OMX Group Inc. and IntercontinentalExchange Inc.

“We embarked on the right strategy five years ago to position the company to benefit over the long-term, and we are not surprised to see other exchanges attempting to follow the same path,” Donohue said in Wednesday’s conference call.

CME Group owns the Chicago Mercantile Exchange, Chicago Board of Trade, New York Mercantile Exchange and has worldwide partnerships with exchanges in Latin America, Europe, Asia, the Middle East and Africa.

Analysts are expecting CME Group to earn $4.27 per share for the quarter ending June 30, compared with actual diluted earnings per share of $4.11 for the same period last year.

The company’s stock closed Wednesday at $304.05, down $5.84.