Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of General Motors (NYSE: GM) were sputtering today, losing as much as 10% in intraday trading after the company reported third-quarter results.

So what: It wasn't current-quarter results that investors are booing today. Sure, earnings per share were down 12% from last year, but at $1.03 they were easily better than analysts' expectations, which is typically investors' biggest concern. Revenue was up 8% year over year to $36.7 billion, roughly in line with estimates.

Now what: The look ahead, however, may be a bit more worrisome for investors. CEO Dan Akerson suggested that a lot of work needs to be done, particularly when it comes to simplifying operations and cutting costs. The company backed off its expectation that European operations would break even by the end of the year. And trouble in that region is likely mingling with the raging concerns about Europe today that are roiling markets broadly.

Should Foolish investors join the stampede and ditch their GM shares? The company's outlook may not be rousing, but this hardly seems to justify the stock's steep drop today.

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Motley Fool newsletter services have recommended buying shares of General Motors. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors.

Fool contributor Matt Koppenheffer does not have a financial interest in any of the companies mentioned. You can check out what Matt is keeping an eye on by visiting his CAPS portfolio, or you can follow Matt on Twitter @KoppTheFool or Facebook. The Fool's disclosure policy prefers dividends over a sharp stick in the eye.