NEW YORK - Shares of General Motors lost nearly one-third of their value Thursday, plunging to their lowest level in more than 58 years after Standard & Poor's said the automaker's credit could fall further into junk status because of the "rapidly weakening state" of the global automotive market.

"These companies certainly wouldn't choose to file bankruptcy, but they could find themselves at a point where their liquidity reached the point where they no longer could run their businesses," S&P analyst Robert Schulz said on Bloomberg Television. "We think they could be pushed into that."

GM shares plummeted $2.15, or 31 percent, to close at $4.76. That low marked the automaker's lowest trade since March 15, 1950, according to the Center for Research in Security Prices at the University of Chicago. At that time, the Korean War was three months away from beginning, and gasoline cost 27 cents a gallon.

Brett Hoselton, an analyst who follows GM stock for KeyBanc Capital Markets, said a number of factors could be behind Thursday's drop, including the decline in banking stocks. "Obviously, GM and Ford, they're closely tied to automotive financing," Hoselton said. "If you can't finance cars, you can't sell cars."

The automobile industry has been bombarded by a spate of gloomy news. Analysts have voiced concerns that the ongoing slump in U.S. vehicle sales could last longer than they previously expected and could spread to other parts of the world, particularly Europe.

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