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 natural gas producer EOG Resources (NYSE: EOG) sank as much as 12% in early Wednesday trading after its quarterly results and output forecast disappointed Mr. Market.

So what: Citing weak natural gas prices, EOG said it swung to a quarterly loss and also cut its production forecasts for 2010, 2011, and 2012. In addition to huge natural gas supplies, EOG is being hurt by delays in securing hydraulic fracturing equipment and higher service costs.

Now what: While it might be tempting to jump on today's plunge in EOG, Fools might do better to look elsewhere first. After all, Devon Energy (NYSE: DVN) is up today on better-than-expected output and trades at a forward P/E discount to EOG. With uncertainty about the amount of capital EOG will need to hit its production growth targets, buying it in a basket with cheaper stocks like Chesapeake (NYSE: CHK), Cimarex (NYSE: XEC), and Devon might be a more prudent bet on natural gas.  

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