UPDATE 3-CME buy of CBOT easily approved by shareholders

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By Ros Krasny

CHICAGO, July 9 (Reuters) - Shareholders of Chicago Mercantile Exchange Holdings Inc CME.N and CBOT Holdings Inc BOT.N voted on Monday to merge the two largest U.S. futures exchanges under one roof.

After an almost 9-month gestation period, the votes delivered one huge, almost $12 billion baby.

CME Group will be the world's largest derivatives exchange and control more than 85 percent of U.S. futures and options-on-futures volume.

"This is the greatest trade in the history of Chicago and I think it's one of the few trades that both sides are big winners," said Charles Carey, chairman of the 159-year-old CBOT.

The deal was easily approved. A competing bid from the upstart Intercontinental Exchange Inc (ICE.N: Quote, Profile, Research, Stock Buzz) was fended off after CME on Friday improved its bid for a third time since original terms were announced in mid-October.

Preliminary results of separate ballots at each exchange showed an "overwhelming" majority in favor of CME's purchase in a package worth about $11.9 billion, exchange officials said.

"Today has been a long time in coming," said Terry Duffy, executive chairman of CME.