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 action sports apparel retailer Zumiez (NASDAQ:ZUMZ) plunged 10% today after its quarterly results and guidance disappointed  Wall Street.

So what: The company's third-quarter EPS managed to top estimates, but a 4.2% same-store sales decline in November, coupled with downbeat guidance for the current quarter, is forcing analysts to lower their valuation estimates yet again. Management cited softer-than-expected sales trends in Europe for the disappointing results, but even more worrisome to Wall Street is how quickly the brand is losing its appeal here at home.

Now what: Management now sees fourth-quarter EPS of $0.59-$0.62 on revenue of $218 million-$221 million, versus Wall Street's view of $0.71 and $222.9 million. "[W]e are confident that the key components of our long-term growth strategy will allow us to profitably expand our share of the global action sports lifestyle market and deliver increased value to our shareholders," CEO Rick Brooks reassured investors. Of course, when you consider the strong economic and competitive headwinds that continue to work against Zumiez, betting on that bullishness seems particularly risky.

Interested in more info on Zumiez? Add it to your watchlist.

Fool contributor Brian Pacampara and The Motley Fool have no positions in the stocks mentioned above. Try any of our Foolish newsletter services free for 30 days. We Fools don't 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.