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 office products distributor United Stationers (Nasdaq: USTR) jumped as much as 14% in intraday trading as investors reacted to the company's fourth-quarter results.

So what: Fourth-quarter revenue was basically flat with 2009, but the $1.2 billion tally matched analysts' estimates. After adjusting for certain one-time gains and expenses during the quarter, earnings per share were $1.17, 19% above last year and well ahead of the expected $1.07. The bottom-line gain was driven in large part by increased margins.

Now what: While the company didn't provide a bottom-line number for 2011 in its earnings release, management was generally upbeat about the year ahead. With the economy slowly recovering, management wants continued improvement and noted that first-quarter sales to date are up 3%. The company is also looking for further margin gains in 2011.

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