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 farm equipment supplier Tractor Supply Co. (Nasdaq: TSCO) climbed as much as 10% Thursday after its fourth-quarter sales topped Wall Street expectations.

So what: Tractor Supply's better-than-expected top line -- revenue for the fourth quarter jumped 20% to $1.24 billion, versus the consensus of $1.2 billion -- prompted management to raise its full-year earnings outlook, as well. The stock is even flirting with its 52-week high on the news, suggesting that Mr. Market fully expects the sales momentum to continue.

Now what: Looking ahead, management sees full-year 2011 EPS of $2.97-$2.99, up nicely from its prior guidance of $2.85-$2.89. "We are very pleased that we have maintained the momentum in our business and are confident in our ability to deliver continued profitable growth," said Chairman and CEO Jim Wright. Of course, with Tractor Supply shares up a whopping 70% over the past year and sporting a forward P/E of 23, the stock might already have plenty of that optimism baked into it.  

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