Now that GMAC LLC has become a bank holding company, there is a silver lining to its ownership of a money-losing mortgage subsidiary.

Becoming a bank holding company, as GMAC did Dec. 24, has breathed new life into the efforts by auto lender GMAC to get affordable funding. But one requirement of being a bank holding company is that its business must be diversified - regulators don't want a bank to be exposed to a single sector, such as auto loans.

So GMAC's Residential Capital LLC unit, despite having racked up $9 billion in losses in recent years, now helps GMAC satisfy that diversification requirement.

GMAC reiterated Thursday in a regulatory filing its support for ResCap, as the struggling mortgage unit is also known. This statement of support differs in tone from dire warnings about limits to its support for ResCap that GMAC made in the weeks preceding its approval for bank-holding status by the Federal Reserve.

"If ResCap were to need additional support," GMAC said in the 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, GMAC indicated its reluctance to take additional action to keep ResCap on life support as GMAC struggled with a $38 billion debt restructuring.

In November, in a stark acknowledgment of ResCap's deteriorating health, GMAC said, "Adverse market conditions have made it difficult for ResCap to maintain adequate capital and liquidity levels. As a result, absent economic support from GMAC, substantial doubt exists regarding ResCap's ability to continue as a going concern."

ResCap posted a third-quarter loss in November of $1.9 billion, bringing its total losses in the last eight quarters to about $9 billion. Its red ink in the third quarter made up the bulk of GMAC's $2.52 billion loss in the same quarter.

Minneapolis-based ResCap, among the largest lenders of risky home loans at the peak of the residential real-estate bubble, is struggling with losses on those mortgages in the current housing slump.

GMAC has made frequent resuscitation attempts in the last several months, giving the mortgage unit capital injections, job cuts, an overhaul of the business and a massive debt restructuring. But continued deterioration in the U.S. housing and credit markets made a quick turnaround unlikely.

In addition to about $8.7 billion in capital injections and loans since 2007, GMAC has forgiven debt owed to it by ResCap. But a paucity of funds and a steady stream of losses made it difficult for GMAC to keep propping up the mortgage unit.

The SEC filing Thursday is "reiterating the importance of the mortgage business to the overall GMAC enterprise," said Gina Proia, a GMAC spokeswoman.

In a separate attempt to diversify its business, GMAC, the financing arm of General Motors Corp. (GM), last week changed its basic financial-services agreement with the auto maker. Under the agreement struck in 2006 when Cerberus Capital Management LLC acquired 51% of GMAC from GM, if GM offered below-market-rate loans, they had to come through GMAC. In exchange, GMAC paid GM an annual fee.

The new agreement allows GM to tap third-party lenders.

And the amended agreement cuts GMAC loose from its obligation to finance GM vehicle leases. Leases have been hurting the lender's bottom line given the steep drop in trade-in values on many GM cars and trucks. This helps GMAC diversify its lending beyond autos.

In addition, GMAC will likely intensify efforts to expand financing to other auto makers.

Turning itself into a bank holding company gives GMAC access to federal funds, including some of the $700 billion set aside to bail out the financial industry.

Shares of GM were at $4.05, down 1.9%, in afternoon trading.

-By Aparajita Saha-Bubna, Dow Jones Newswires; 201-938-2137; aparajita.saha-bubna@dowjones.com

(Jim Jelter of MarketWatch contributed to this report.)

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