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 youth-skewed-apparel retailer Urban Outfitters (Nasdaq: URBN) are as popular as last year's fashion today, falling as much as 16.4% on tremendous trading volume.

So what: Last night's fourth-quarter report missed analyst targets on both the top and bottom lines as the company chased sales through aggressive clearance markdowns and still came up short.

Now what: CEO Glen Senk was happy to report record sales and operating profit, but investors still wanted more, and that operating benchmark was set by a very slim margin. Slimming profiles are more flattering on young bodies than financial statements, dude. Rivals such as Abercrombie & Fitch (NYSE: ANF) and Pacific Sunwear of California (Nasdaq: PSUN) hardly moved on the news, indicating a widespread belief that the problems were Urban Outfitters' own and not a sudden, industrywide shift in fashion tastes.

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