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 nutritional products retailer Vitamin Shoppe (NYSE:VSI) crashed 20% today after its quarterly results disappointed Wall Street.

So what: The stock has soared over the past year on strong sales momentum, but a clear fourth-quarter revenue miss -- $218.9 million versus the consensus of $223.2 million -- is triggering concerns over slowing growth going forward. While management blamed the miss on Hurricane Sandy, analysts are being forced to recalibrate their valuation estimates in case there are more serious competitive and consumer demand issues at play.

Now what: For 2013, management said it plans to open about 50 new stores and maintained its same-store sales outlook of mid-single-digit growth. "Initiatives undertaken in the past year, including accelerating new product development, improving our customers' online shopping experience, testing small market stores, and opening our first stores in Canada, have positioned us well for long-term sustainable growth," said CEO Tony Truesdale. With the stock still up more than 20% from its 52-week lows and trading at a 20-plus forward P/E, however, I'd wait for even more of a pullback before buying into that bull talk.

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