DETROIT (AP) — Shares of General Motors Co. slipped Monday even as an analyst told investors that the company's initial moves to double its credit line made sense.

Citi Investment Research analyst Itay Michaeli wrote in a note to investors that raising the $5 billion credit facility and extending its maturity will boost GM's already strong balance sheet. The company may be preparing to spend some of its $33 billion in cash and operate with a lower balance, Michaeli wrote.

GM is in the process of restructuring its money-losing European operations, but its cash flow generation should be enough to support that, Michaeli told investors on Monday. So raising the credit line could be a move to cut costs by reducing the company's obligation to its hourly workers' pension plan, or it could buy back shares to help boost the stock price, he wrote.

"A decision to run lower cash balances would likely be one of deployment," Michaeli wrote.

The Wall Street Journal on Friday reported that GM was in preliminary talks with banks to possibly double the size of its credit line. The company's current credit facility is about half that of rival Ford Motor Co.

GM now pays pensions to a whopping 400,000 blue-collar retirees and their spouses in the U.S. Its hourly pension plan has about $71 billion, $10 billion short of its obligations. Earlier this summer, GM changed the way it makes pension payments to white-collar retirees, shoring up its finances by offering buyouts and shifting liabilities to an insurance company annuity.

The moves were to unload $26 billion in pension liabilities from the Detroit automaker's books, and experts said the changes are likely the start of a trend as companies with defined benefit pension plans try to cut risk and administrative costs.

GM spokesman Jim Cain wouldn't comment Monday on the credit line reports.

On Friday, Fitch Ratings agency upgraded GM's credit rating from BB to BB+, one notch shy of investment grade. An investment grade rating would bring the company lower borrowing costs. Fitch said the upgrade is due to GM's continued positive cash flow, low leverage, strong liquidity, reduced pension obligations and improved product portfolio.

Shares of GM fell 12 cents to $21.06 in morning trading Monday. In the past year they have traded in a range of $18.72 to $27.68, well below the company's initial public offering price of $33 in November 2010. GM returned to the public markets after emerging from a government-funded bankruptcy in 2009.