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 Ion Geophysical (NYSE: IO) fell 10% today after the company released earnings.

So what: Fourth-quarter revenues barely budged from a year earlier, coming in at $159.9 million. Net income was $12 million, but when you strip out "special items," earnings were a much more impressive $23.2 million, or $0.15 per share, in line with estimates.

Now what: Full-year numbers were similar with revenue barely growing over last year. With all of the expansion in drilling both on and offshore, expectations for growth are higher than Ion is giving, hence the drop in shares today. 2011 earnings per share were just $0.22, meaning shares are trading at 33 times trailing earnings, a steep price for a company that isn't growing revenue at a rapid pace.

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Fool contributor Travis Hoium does not have a position in any company mentioned. You can follow Travis on Twitter at @FlushDrawFool, check out his personal stock holdings or follow his CAPS picks at TMFFlushDraw.

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