Corzine, who resigned as CEO of the commodities brokerage Nov. 3., said he was stunned to learn shortly before the firm filed for bankruptcy at the end of October that it could not account for "many hundreds of millions of dollars of client money."
The one-time U.S. senator said he did not generally involve himself in the mechanics of the clearing and settlement of trades, or in the movement of cash and collateral.
"I simply do not know where the money is, or why the accounts have not been reconciled to date," Corzine said in testimony prepared for delivery Thursday to Congress. "I do not know which accounts are unreconciled or whether the unreconciled accounts were or were not subject to the segregation rules."
The firm, which is now in liquidation, was required to keep clients' money separated from its own, the Washington Post said.
More than $1.2 billion may be missing, the newspaper said.
"I sincerely apologize, both personally and on behalf of the company, to our customers, our employees and our investors, who are bearing the brunt of the impact of the firm's bankruptcy," Corzine said