NEW YORK (APP) - The hunt for the missing $600 million in customer money at MF Global Holdings Ltd may begin with Harris Bank, a Chicago-based lender that often holds client money for many large futures brokerage firms. A Harris Bank branch office in downtown Chicago was the main repository for money from many of MF Globals 150,000 customers, according to customers and representatives with smaller investment firms that introduced clients to the New York-based brokerage. Harris Bank, a division of the Bank of Montreal, is emerging as a starting point in the investigation by federal authorities, who are trying to determine what happened to more than $600 million in MF Global customer money that remains unaccounted for eight days after the firm collapsed in bankruptcy. A person familiar with a preliminary investigation by the Federal Bureau of Investigation says one of the things authorities are looking into is what happened with the customer money held in segregated accounts at Harris Bank. A segregated account is a separate account used by brokers to keep their customers money separate from the firms money. A spokesman for Harris Bank says the bank is prohibited by confidentiality laws from discussing the customer accounts. Lawyers representing Harris Bank in the MF Global bankruptcy did not return a phone call or email seeking comment.