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 maker ACCO Brands (NYSE:ACCO) dropped 17% today after the company reported earnings.

So what: Third-quarter revenue was down 6.4% from a year ago to $469.2 million, well below the $488.1 million estimate from Wall Street. On the bottom line, earnings of $0.25 per share were $0.08 worse than estimated. 

To make matters worse, the company guided full-year earnings of $0.78 to $0.81 per share, below the consensus $0.88 estimate.

Now what: There was really weakness across the business, and management expects full-year revenue to decline mid- to high single digits. That's not the kind of trajectory you want out of any company, and it makes this stock look like a value trap. Shares trade at just seven times the top end of this year's estimates, but with conditions getting worse, I still don't see that as a good value for investors.

Fool contributor Travis Hoium has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.