It's unusual for a former member of Congress to testify on an issue under federal investigation, but a congressional panel is making an exception with former senator Jon Corzine. Corzine has been asked to speak about his role as chairman and CEO of MF Global, the brokerage firm that folded this fall and subsequently went bankrupt. The House Agriculture Committee called for Corzine's subpoena, saying it's "essential to fulfill our objectives," since Corzine didn't respond to an informal request for testimony. Federal regulators are investigating whether MF Global attempted to use customers' money to support its own trades.
