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 Zumiez (Nasdaq: ZUMZ) fell 10% at the open this morning after the company released earnings.

So what: The earnings report wasn't nearly as bad as you might think with the stock down today. Revenue of $156.2 million beat estimates of $155.7 million and earnings per share of $0.49 beat estimates by a penny. It was the first-quarter outlook of an EPS loss of $0.03 to flat that disappointed investors today.

Now what: Analysts only expected earnings of a penny, but with Zumiez's range below that, investors got a little worried. It was this kind of outlook that made Zumiez a Motley Fool Big Short short-sale pick, and a cloud appears to be hanging over trendy retailers. Aeropostale (NYSE: ARO) is also lower today after disappointing earnings, so I would tread around the sector carefully today.

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

Fool contributor Travis Hoium does not have a position in any company mentioned. You can follow Travis on Twitter at @FlushDrawFool, check out his personal stock holdings or follow his CAPS picks at TMFFlushDraw.

Zumiez is a Motley Fool Big Short short-sale choice. Motley Fool Alpha has written calls on Zumiez. The Fool owns shares of Aeropostale. 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.