WASHINGTON — The government was moving ahead today on a fresh multibillion dollar cash infusion to stabilize auto financing company GMAC Financial Services, according to a person with knowledge of the matter.

GMAC, based in Detroit, is instrumental to the operations of automakers General Motors and Chrysler. It has already received $12.5 billion in taxpayer money and is 35 percent owned by the federal government.

The person, who spoke on condition of anonymity because discussions weren't complete, said the new infusion would be in the range of another $3 billion. That would fall short of the roughly $6 billion the government had earlier thought GMAC would need to stabilize the company.

An announcement of the injection could come late today or on Thursday, the person said.