GMAC Financial Services announced in a regulatory filing yesterday that chief financial officer (CFO) Robert Hull "elected to depart" the company, effective at the end of March. The news of his resignation arrives after GMAC mortgage operations subsidiary Residential Capital (ResCap) said last week it is addressing credit-rating agency "concerns" over the servicing of certain mortgage securities. In particular, Moody's Investors Service raised concern over ResCap's practice of netting cash flows of multiple residential mortgage-backed security (RMBS) deals in a shared custodial bank account. ResCap said it is separating the trusts into individual custodial bank accounts, which it believes will resolve any issues. It's business as usual at GMAC Financial Services in the wake of Hull's resignation. The company said in a filing with the Securities Exchange Commission (SEC) (download the filing here) it will launch an internal and external search for CFO candidates. A company spokesperson told HousingWire Hull will return to the Boston area full-time where he and his family permanently reside. He commuted from there to New York since joining GMAC in December 2007. "Rob has presided in the CFO role during some of the most critical moments in GMAC’s history and we thank him for his service," the spokesperson said. Hull's departure from GMAC comes at a time when the mortgage finance industry seems to be suffering a personnel crisis. As HousingWire previously reported, the Federal Housing Finance Agency (FHFA) is without independent oversight, as its independent inspector general position has been vacant for almost a year. Deutsche Bank saw head of securitization research, Karen Weaver, and head of MBS research, Art Frank, recently leave. The personnel crisis is not unique to the US. French investment bank Société Générale suffered a brain drain last year as players in the asset-backed securities (ABS) market left the London office. Write to Diana Golobay.