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 utility-meter manufacturer Itron (Nasdaq: ITRI) slipped as much as 13% after a disappointing fourth-quarter earnings report.

So what: Itron's fourth-quarter earnings per share made an impressive jump from $0.13 in the fourth quarter of last year to $0.65 this year. Revenue grew 30% year over year while expenses were up just 9% and interest expense fell. However, adjusted EPS, which excludes amortization costs, came in at $0.95, below the $1.05 that analysts were expecting.

Now what: The bad news continued with the 2011 outlook. Management expects 2011 revenue between $2.15 billion and $2.3 billion, which, at the high end, is slightly below the $2.33 billion Wall Street had estimated. Earnings per share are seen coming in between $3.95 and $4.40, which captures Wall Street's expected $4.38, but would require the company to be at the high end of its guidance. Investors may need to slightly temper their expectations due to management's guidance, but after an impressive 2010 the market's rush to sell today seems a bit overdone. 

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Fool contributor
Matt Koppenheffer does not own shares of 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 on his RSS feed. The Fool's disclosure policy prefers dividends over a sharp stick in the eye.