Bond investing giant PIMCO has made an investment in Citadel Servicing, a small but fast-growing nonprime lender that could wind up originating $400 million in non-agency residential loans next year. Industry officials confirmed the investment to Inside Nonconforming Markets, although neither company would comment. One source close to the transaction said PIMCO’s stake in Citadel is under 30 percent. The lender, which raised $200 million in seed money early last year, has been funding ...