GM: ResCap May Ram Auto Finance

GM, which has four executives on GMAC's board, has said it is under no contractual obligation to provide the finance company with any more capital infusions beyond a $1 billion equity contribution it has made since the sale.

For its part, Cerberus is exploring a possible merger for ResCap with an overseas mortgage company. But if no alterative is forthcoming, GM could still be forced to pour more cash into GMAC to protect its credit ratings.

"We sensed GM's more likely to allow its GMAC ownership to be diluted down to levels that still maintain its minority rights before funding a ResCap bailout," said NesVold.

Shares of GM recently were up 62 cents, or 2.1%, to $29.41.