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 lighting company Acuity Brands (NYSE: AYI) climbed 10% on Monday after its quarterly results topped Wall Street expectations.

So what: The stock has slumped in recent months on concerns over rapidly rising expenses, but today's third-quarter earnings beat -- adjusted EPS of $0.82 versus the consensus of $0.79 -- is quickly easing some of those worries. While the company continues to face higher material and component costs, improved sales volumes and price increases are helping offset some of the margin pressure.

Now what: I wouldn't be so quick to ride this wave of momentum. "While we are optimistic about our future prospects and ability to outperform the markets we serve, we do see the potential for continuing volatility in demand due to the weak pace of economic recovery in the United States and globally," cautioned Chairman and CEO Vernon Nagel. With a still-hefty debt load and a 20-plus P/E, I'd wait for a wider margin of safety before taking on that uncertainty.  

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Fool contributor Brian Pacampara owns no position in any of the companies mentioned. Try any of our Foolish newsletter services free for 30 days.

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