CBOT Holdings shareholders approved the $11.3 billion merger agreement with Chicago Mercantile Exchange Holdings Inc., ending a three-month battle to create the world’s largest futures exchange.

“They’ve approved it,” said Allan Schoenberg, a spokesman for the Chicago Mercantile Exchange.

The Chicago Mercantile prevailed over an unsolicited $11.8 billion offer from Atlanta-based Intercontinental Exchange. The bidding war, sparked in March by ICE CEO Jeff Sprecher, forced the Chicago Merc to improve its bid three times.

“The merger makes more sense than any other exchanges,” Will Vicars, managing director at Caledonia Investments Ltd., the Board of Trade’s largest shareholder.

The Chicago Merc gained Caledonia’s support July 6 when it increased its offer by 7 percent. Caledonia said last week that it had voted against the previous offer. Shareholders had until yesterday to vote or change their vote.

The Chicago Merc’s original offer, in October, was 0.3006 of a share for each CBOT share. It increased that to 0.35 a share in May before its final increase to 0.375 shares last week.

Intercontinental offered 1.42 shares of its stock for each share of CBOT. The merger prices vary with the closing shares of each company’s stock.

Bloomberg