From the NYT:

Investigators have determined what happened to nearly all of the customer money that disappeared from MF Global around the time of its bankruptcy last Oct. 31, but have not publicly disclosed their progress, fearing that doing so might cripple efforts to recover the cash and pursue potential wrongdoing, people briefed on the investigation said.

While authorities have traced hundreds of millions of dollars to banks, MF Global’s trading partners and even the firm’s securities customers, investigators remain uncertain about whether they can retrieve the money.

Some recipients were entitled to payouts from MF Global, which could make clawing back the money difficult. For instance, securities customers withdrawing their money as MF Global began to collapse were paid from accounts that belonged to futures clients, according to other people briefed on the matter.

For more, see: After a Delay, MF Global’s Missing Money Is Traced