MF Global shortfall could exceed ... $1.2 billion

Regulators currently suspect that MF Global improperly used customer money for its own purposes in the days before filing for Chapter 11 protection, according to people briefed on the matter.

The decision to release the updated figure on Monday came after authorities concluded that much of the customer money had left the firm, these people said.

By MF Global’s estimates to regulators, roughly $600 million in customer money was missing. But as forensic accountants pored over MF Global’s books in recent weeks, they began to question those estimates.