In its thirst to expand further into financial services, IBM recently agreed to buy blue-chip advisory firm Promontory Financial Group, but there are two units that “Big Blue” won’t be getting: Promontory MortgagePath LLC and Promontory Interfinancial. According to industry officials, both units will continue to be owned (at least in part) by PFG founder Eugene Ludwig, the former Comptroller of the Currency who started the firm in 2001. Promontory Interfinancial is considered...