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 rue21 (Nasdaq: RUE) fell 10% briefly this morning after the company released fourth-quarter results.

So what: Revenue rose 16% to $219.9 million, and earnings per share were $0.52, slightly ahead of estimates. It was guidance that investors had their eyes on today. Management said first-quarter earnings per share would be $0.42 to $0.44 next quarter and $1.74 to $1.79 for the full year, near the bottom of analysts' expectations.

Now what: The guidance wasn't all that bad, considering it was still in line with what analysts had expected. But sales at stores open at least a year fell slightly in the fourth quarter, always a warning sign for retail investors. I wouldn't panic-sell here, but I'm also not a buyer considering the same-store sales drop.

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