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 specialty value retailer Five Below (NASDAQ: FIVE) surged 15% today after its quarterly results and outlook topped Wall Street expectations.

So what: The stock has been on a roller coaster in 2013 on uncertainty over sustainable growth, but today's second-quarter results -- adjusted EPS spiked 175% on a revenue increase of 35% -- suggest that management is making solid market share headway. In fact, comparable store sales grew 6.6% over the year-ago period, giving analysts plenty of good vibes over its competitive position and ability to grow profitably.

Now what: Management now sees full-year adjusted EPS of $0.68-$0.71 on revenue of $531 million-$536 million, above its prior view of $0.65-$0.68 on revenue of $524 million-$529 million. "We believe the performance of both our new and existing stores, as well as strong execution by the entire Five Below team, have us well-positioned to deliver on our goals for the year," said Co-Founder and CEO Thomas Vellios. Of course, with the stock busting through its 52-week high today and trading at a 40-plus forward P/E, much of that bullishness might already be baked into the valuation.

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Fool contributor Brian Pacampara has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.