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 women's apparel company Chico's FAS (NYSE: CHS) sank 16% on Tuesday after its third-quarter results disappointed Wall Street.  

So what: Chico's sales have been helped recently by bargain-hungry shoppers, but today's miss -- EPS of $0.16 versus the consensus of $0.20 -- shows that those discounts are cutting much deeper into margins than analysts had expected. In fact, the shares are hitting a new 52-week low on the news and are down 40% over the past four months alone.

Now what: I'd look into this plunge as a possible buying opportunity. Management also said on Tuesday that it plans to repurchase up to $200 million worth of its shares, suggesting that they represent pretty good value. The margin trend is certainly worrisome, but with Chico's shares trading at a forward P/E discount to rivals like Macy's (NYSE: M) and Nordstrom (NYSE: JWN), much of the bad news might already be baked into the price.

Interested in more info on Chico's? Add it to your watchlist.