You’d think $1.2 billion would be a large enough sum to not go missing for long. But one thing’s becoming increasingly clear: Tracking down the lost funds of MF Global customers won’t be easy. The New York–based broker-dealer collapsed as a result of bets that then-CEO Jon Corzine made on European sovereign debt, filing for bankruptcy on October 31. During the firm’s frantic final days, it looked like some of the missing money might be found at JPMorgan Chase & Co. For its part, the bank has said that it was just a conduit for the funds and is making every effort to assist regulators as they hunt for the missing money. Also, MF Global executives blamed part of the problems leading up to the collapse on the slow delivery of funds from....