DETROIT — Delphi's bankruptcy filing raised new questions yesterday about the fate of General Motors, its biggest customer and former parent company, prompting Standard & Poor's to cut the automaker's rating further into junk status and one analyst to say GM's chance of filing for Chapter 11 jumped higher.

The entire industry has been rocked by escalating raw material prices, reduced automaker production and soaring benefit and labor costs.

Shares of GM fell 10 percent yesterday, closing at $25.48. Delphi's shares fell 70 percent to 33 cents, and the New York Stock Exchange said it is reviewing Delphi's eligibility to stay listed.

Banc of America analyst Ron Tadross says GM's risk of bankruptcy in the next two years increased from 10 percent to 30 percent. Delphi's bankruptcy filing could trigger a contractual obligation that would force GM to pick up the tab for many Delphi retirees. GM estimates that could add up to $11 billion to its expenses.

"This, and our strong belief that the UAW will be tougher on GM than Delphi, should get GM to more seriously consider bankruptcy protection," Tadross wrote in a note to investors.

S&P said it sees "potential for a disruptive strike in the future" at Delphi, which could shut down production at GM plants in as little as two days.

Delphi has long complained that its labor and retiree costs, which were negotiated when the supplier was spun off from GM in 1999, are burdensome.

Talks between GM and Delphi broke down a week before the filing. Delphi said talks with the unions were going well, but the supplier couldn't get GM to help modify the contracts.

"GM's steadfast refusal to write an open-ended check to the UAW shows a new willingness to play hardball," Brian Johnson, an analyst at Sanford Bernstein, said.

"It really is a shot across the bow of the UAW," says David Cole, chairman of the Center for Automotive Research. "It basically says the old game is over, and the new game is survival."

When GM spun off Delphi, union workers continued to receive wages on par with laborers at automotive plants. But suppliers generally pay nearly half that to their hourly workers. Combined with benefits, Delphi workers make an average of $63 an hour, the company says.

The UAW "can no longer negotiate wages and benefits that aren't consistent with what the market is willing to pay," Cole says.