Did MF Global use its own customers' money to support its faulty trades? Were they just sloppy? Are banks simply refusing to send the troubled firm its own money?
Regulators don't know. What is known is that the sale of a large part of MF Global to Interactive Brokers Group -- a deal that seemed all but completed on Sunday -- collapsed because of the missing money.
MF Global hasn't been accused of anything sinister, and neither has Corzine. But as investigations continue, that could change.