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 The Buckle (NYSE: BKE) sank 13% today after its quarterly earnings missed Wall Street expectations.

So what: Despite solid revenue growth of 11.8%, Buckle's first-quarter profit of $33.5 million, or $0.71 per share, came in below the average analyst estimate of $0.73 per share. That doesn't seem like a particularly big miss, but given how nicely Buckle's shares had been rallying over the past several months, it's obvious that Mr. Market is starting to expect a whole lot more.   

Now what: I'd look into this quarterly miss as a possible long-term opportunity. Buckle's merchandise continues to have strong growth as evidenced by its market-beating top line and still boasts operating margins double that of rivals Abercrombie & Fitch (NYSE: ANF) and American Eagle (NYSE: AEO). Most importantly, with the stock now sporting a forward P/E of 13, Buckle seems reasonably priced, as well.

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