US regulators investigating the collapse of MF Global have widened their inquiry to the CME Group, which operates the massive exchange where the firm did business, the New York Times reported Friday. The Commodities Futures Trading Commission (CFTC) -- which is probing the disappearance of some $1.2 billion in customer funds from MF Global -- is looking into CME\'s actions in the days before the Wall Street firm\'s filing for bankruptcy on October 31, 2011, the Times said, citing unnamed sources. The Chicago-based CME Group, which owns the Chicago Mercantile Exchange, the Chicago Board of Trade and the New York Mercantile Exchange, operates the world\'s largest futures market. CME, which has not been accused of any wrongdoing, said it welcomed the investigation and did not expect to be faulted. \"Given the issues involved, we welcome and expect the CFTC’s investigation as a natural part of this process,\" a CME spokeswoman said in a statement quoted by the Times. \"We are confident the CFTC’s review will determine we did everything right within our regulatory power. The system did not fail; the firm broke the law by misusing customer funds.\" MF Global collapsed in October after making vast bets on European sovereign debt -- particularly Belgium, Italy, Spain, Ireland and Portugal -- that turned sour amid the eurozone financial crisis.