CME Group, parent company of the Dow Jones industrial index, was subpoenaed in November "to produce information and witnesses in connection with" the ongoing investigation of broker-dealer MF Global. Collapsed and bankrupt, MF Global is accused of mishandling more than $1.6 billion in customer funds.

A Chicago-based grand jury's subpoena of CME does not mean charges are pending against the company, but "grand juries aren't convened unless there is a very strong feeling, as in this case, that there has been some criminality," explained Buchanan Litigation Shareholder Barry I. Slotnick in the Financial Times on February 28, 2012.

A slew of federal regulators – including the FBI and the Securities and Exchange Commission – launched an investigation into MF Global after the company filed for bankruptcy. As the article explains, CME claims it was only made aware of MF Global's fund shortfall after the broker-dealer filed for bankruptcy.