GMAC LLC reiterated its support Thursday for Residential Capital LLC, its struggling mortgage unit.

The statement of support differed in tone from dire warnings GMAC made in the weeks preceding its approval for bank holding company status by the Federal Reserve Board.

"If ResCap were to need additional support," GMAC said in a Securities and Exchange Commission filing Thursday, "GMAC would provide that support so long as it was in the best interests of GMAC stakeholders."

As recently as last month it had indicated its reluctance to take additional action to keep ResCap on life support as its parent struggled with a $38 billion debt restructuring.

In November, in a stark acknowledgment of the unit's deteriorating health, GMAC said: "Absent economic support from GMAC, substantial doubt exists regarding ResCap's ability to continue as a going concern."

One requirement of being a bank holding company is that its business must be diversified; regulators frown on excessive exposure to a single sector, such as auto loans. ResCap, despite its $9 billion of losses in recent years, would help GMAC satisfy the diversification requirement.

Subscribe Now

Access to authoritative analysis and perspective and our data-driven report series.

14-Day Free Trial

No credit card required. Complete access to articles, breaking news and industry data.