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 supplier ACCO Brands (NYSE: ACCO) were giving investors paper cuts today, falling as much as 16% after the company cut its full-year guidance.

So what: Adjusted earnings of $0.26 per share actually beat estimates of $0.20, and revenue rose 33% to $438.7 million, boosted by the company's acquisition of MeadWestvaco, but fell far short of estimates of $468.3 million. Sales at its international division declined 7% as the company cut production of low-margin products to Europe and Australia. The company, which makes the iconic Trapper Keeper, cut its annual guidance from $1.06 per share all the way down to $0.82-$0.85, though it did predict a $0.20 EPS gain in 2013. Management blamed softening in Europe for two-thirds of the reduction.

Now what: This seems like run-of-the-mill cyclical weakness based on currency exchange rates and slower demand. While no investor likes to see sales projections down 8%, it's worth giving the company a chance to redeem its acquisition and take advantage of the cost synergies it's promised. With shares down more than 40% over the last four months, ACCO's forward P/E sits at just 6.6. Shareholders who haven't bailed yet should be better off waiting for a rebound.

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