GMAC, the financial services group owned by Cerberus Capital Management and General Motors, is considering the sale of at least part of Residential Capital, its troubled mortgage lender, after a hefty fourth-quarter loss.

GMAC posted a net loss of $724m, a sharp reversal from a profit of $1bn a year earlier. ResCap’s loss grew to $921m from $128m while earnings from motor vehicle financing slipped to $137m from $593m.