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June 17 (Reuters) - Exchange operator CME Group CME.O on Wednesday named insider Lynne Fitzpatrick its next CEO, succeeding longtime chief Terry Duffy, who will become executive chairman.

Fitzpatrick, currently CME's president and chief financial officer, will also join the company's board when she takes over as chief executive, CME said. Shares of CME were last down 4% in premarket trading.

She takes over at a time exchanges are increasingly seeking growth beyond their traditional role as stock and derivative marketplaces.

The industry has expanded into areas ranging from market data and software to prediction markets, reflecting a broader effort to attract new customers and diversify revenue streams.

Duffy, who was appointed chairman in 2002 and has led CME for more than 25 years, will step down on March 1. "CME Group has grown from a Chicago institution to a true global powerhouse – all while generating billions in daily efficiencies for market users globally," he said in a statement.

Since Duffy took CME public in 2002, the company's stock has gained more than 8,000%, lifting its market value to about $95 billion. It traded at an average daily volume of 28.1 million contracts last year.

He also steered it through the global financial crisis and completed the industry's first merger with cross-town rival the Chicago Board of Trade in 2007.