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: Masco (NYSE: MAS) dropped 11% in intraday trading today after the home improvement and building products company reported fourth-quarter EPS that fell shy of expectations, and management said it expects the business environment to remain challenging.

So what: Non-GAAP ("before bad stuff") EPS of -$0.08 came in $0.06 below the consensus estimate and compared unfavorably to EPS of $0.07 in the year-ago quarter. Management blamed the disappointing results on the end of the homebuyer tax credit, increasing commodity costs, and the competitive environment.  

Now what: The sales decline is accelerating, and GAAP ("including bad stuff") EPS for the quarter was a whopping -$2.96, reflecting $798 million in impairment charges. Impairment charges are taken when company management moves past the denial stage and admits that its earnings expectations related to the impaired assets were overly optimistic. Management's dismal outlook, the weak housing market, and the impairment charges all suggest the stock is dead money for at least a couple of quarters.  

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Fool contributor Cindy Johnson does not own shares of any company named above. 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.