Shares of General Motors are tumbling more than 10 percent today, touching levels not seen since 1955.

Yes, nineteen-hundred and fifty-five. Okay, it's 1955 with an asterisk, as will be explained below, but still. We're talking about Eisenhower's Cold War America. Pre-credit crunch, pre-internet, indeed it goes back to a time before many investors and companies even existed.

Such a grand span of time is comparable to the life of an empire, which is what General Motors is: a fallen empire.

Shares of G.M. have been on a long downward slope since Rick Wagoner became chief executive in 2000, falling more than 70 percent. High gasoline prices are hurting sales of trucks and S.U.V.'s The company has been bleeding cash and losing market share to Toyota and others for some time and has not been profitable since 2004.

Today's sell-off was triggered by a note by Patrick Archambault, an analyst with Goldman Sachs, who cut his six-month price target on G.M. shares to $11 from $19.

"We think G.M.'s automotive cash flow burn this year and next is likely to lead it to look to raise capital, which we believe could lead to significant shareholder dilution and/or a cut to the company's dividend," Archambault wrote.

Shares of G.M. slid to $11.32, dragging down the Dow Jones industrial average, which includes the automaker as one of its 30 components. To be sure, at $11 a share, G.M. is at 1955 levels only nominally: Investors over the last 43 years benefited from dividends and from several stock distributions, like the spinoff of Hughes Electronics. (There were stock splits in September 1955 and in 1989.)

Here's a more telling sign: General Motors' market value is now only $6.5 billion. Toyota's? $149 billion.

If 2008 is the beginning of the end for General Motors, 1955 was the start of its global glory.

That year, the company became the first American corporation to pay more than $1 billion in taxes. Sales of its cars and trucks topped 5 million. It had more than $12 billion in revenue, and 525,000 employees in the United States. (In 2007, it had $181 billion in revenue and 284,000 employees worldwide.)

In 1955, Time named G.M.'s chief executive, Harlow Curtice, as its man of the year. Two years earlier, one of the company's presidents, Charles Wilson, was nominated to be Defense Secretary. At his confirmation hearing, he said that he "thought that what was good for our country was good for General Motors, and vice versa.''

Of course, that got turned around as: What's good for General Motors is good the country.

Nearly a half century later, is what's bad for General Motors, bad for the country?