Citadel Servicing has increased its portfolio of nonprime mortgages in the past year and has taken steps to improve operations, according to Fitch Ratings. Citadel serviced mortgages with an unpaid principal balance of $1.1 billion as of the end of November, up from a $673.1 million portfolio as of the end of 2016. Some 1.8 percent of Citadel’s portfolio was 30 or more days delinquent as of November, according to Fitch. A significant portion of the portfolio was originated after ...