The U.S Department of Justice gave the green light for two of the largest futures exchanges to merge, saying the merger would not hurt competition.

A statement released by the Department's antitrust unit gave it's go-ahead to the mega-merger between the Chicago Mercantile Exchange Holdings Inc. (NYSE: CME) and the Chicago Board of Trade Holdings Inc., (NYSE: BOT) concluding that the evidence does not indicate that either the transaction or the clearing agreement is likely to reduce competition substantially.

The proposed combination would create the world's largest derivatives exchange. Despite clearance from regulatory bodies, the deal is far from certain.

Shareholders are expected to vote on the proposed merger on July 9. However they still need to consider a bid made by Atlanta's IntercontinentalExchange Inc. in March.

ICE's all stock-offer for CBOT is valued at about $11.2 billion, or $900 million more than CME's proposal. The CBOT board rejected the ICE bid in May, citing execution risks.

CBOT is leaning towards CME, however, with the board recently endorsing a recently sweetened offer in May on top of an initial proposal in October.

A combined CME and CBOT would have more than 85 percent of the U.S. futures and options on futures market, including close to 100 percent in the interest rate and stock index segments.