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 teen retailer Zumiez (Nasdaq: ZUMZ) went out of style quickly Thursday and fell 16% in intraday trading.

So what: July same-store sales increased 4.9% but fell short of the 7.5% investors were expecting. There were high expectations partly because same-store sales grew 9.4% last year, and investors were hoping for a repeat performance.

Now what: On the plus side, total sales grew 12.3% to $38.7 million, so the business is growing at a healthy level. Investors may be worried about the growth today, but with shares trading at 17 times forward earnings, I think this is a nice discount for those looking to buy. Worries might persist in the coming weeks about economic growth that could put pressure on shares, but I think we're reaching buying territory.

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