CME, Bats closely monitor markets ahead of Brexit vote

(Adds comment from Bats, details on opinion polls)

By Tom Polansek

CHICAGO, June 13 (Reuters) - Global exchange operators are scrutinizing trading activity ahead of Britain's vote on whether to leave the EU amid expectations the referendum may spark sharp moves in currencies and other markets.

CME Group Inc (NasdaqGS: CME - news) , one of the world's biggest financial exchange operators, "will be continuously and actively monitoring for market impacts" related to the June 23 vote from its Global Command Center in Chicago, according to a notice sent to customers on Monday.

The command center, which is CME's market operations and customer service desk for electronic trading, will "take any action it deems necessary, in its sole discretion, to preserve market integrity," the notice said. Actions ahead of the vote could include modifying limits on price fluctuations and messaging.

A British exit would rock the European Union, already shaken by differences over migration and the future of the euro zone, by ripping away its second-largest economy, one of its top two military powers and by far its richest financial center.

Britain's "Out" campaign has widened its lead over the "In" camp ahead of the vote, according to two opinion polls published by ICM on Monday. They are the latest to suggest that momentum has swung toward the "Out" camp, unsettling investors.

As the vote nears, Bats Global Markets Inc, the second-largest U.S (Other OTC: UBGXF - news) . equities market operator, "will be engaged in detailed monitoring of all trading on the Bats markets, and the market overall," a spokesman said.

A Brexit would probably be negative for overall equity market volumes, Mark Hemsley, chief executive officer of Bats Europe, has told Reuters.

Many analysts reckon an exit vote also would send sterling tumbling by 15 percent to 20 percent, while a vote to stay would likely drive the currency sharply higher.

(Additional aeporting by Ann Saphir in San Francisco and Chuck Mikolajczak in New York, editing by G Crosse and Tom Brown)