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 office supply retailer Staples (Nasdaq: SPLS) plummeted 16% on Wednesday after its quarterly results and full-year outlook came in below Wall Street estimates.

So what: Hurt primarily by weaker-than-expected sales, the company posted a first-quarter profit of $198.2 million, or $0.28 per share, versus the average analyst estimate of $0.32 per share. With the miss coming less than a month after smaller foes Office Depot (NYSE: ODP) and OfficeMax (NYSE: OMX) also reported disappointing quarters, investors seem to be worried that the office supply space, as a whole, might be facing a more serious secular decline.    

Now what: Management now sees full-year earnings of between $1.35 and $1.45 per share. Although the outlook also came in below Wall Street estimates, today's big sell-off leaves the stock trading at less than 12 times the midpoint of that range, suggesting a possible opportunity. While the overall revenue trend is concerning, Staples' continued market share gains in North America and better-than-expected international sales are a pair of positives value hunters can hang their hat on.

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