An investigation into the bankruptcy of MF Global Holdings was expanded to include CME Group, sources said. The Commodity Futures Trading Commission reportedly is looking into whether CME's supervision was sufficient. "Given the issues involved, we welcome and expect the CFTC's investigation as a natural part of this process," a CME spokeswoman said. "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."