Standard & Poor's has downgraded the credit rating of the CME Group to AA-. Part of the reason for the donwgrade, as explained by the credit ratings agency, is the MF Global scandal.

"CME Group Inc. is increasing its financial and credit risk profiles, in our opinion, due to the sudden growth of its over-the-counter clearing business and the newly provided protection it has extended to the trading customers of its defaulted clearing members," explained S&P in a statement. "The outlook reflects our view of the potential legal and reputational fall-out from the MF Global bankruptcy."

The CME Group was recently awarded a much-maligned corportate tax break by the Illinois General Assembly.