General Motors revealed yesterday that it's considering selling a controlling stake in its finance arm, General Motors Acceptance Corp. This revelation comes despite the fact that GMAC actually makes money for GM. It's expected to earn $2.5 billion this year alone. The move is actually meant to save the company from GM's abysmal credit rating, which makes it difficult for GMAC to borrow money. By selling a controlling stake in GMAC, which is valued at $12 to $15 billion, GM hopes that creditors will improve the finance company's credit rating from junk to investment-grade.