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 waste-to-energy company Covanta (NYSE:CVA) fell 12.4% today after the company reported earnings.

So what: Third quarter revenue rose 3.6% to $427 million, and net income from continuing operations rose slightly to $28 million, or $0.28 per share. Revenue was in-line with estimates and earnings were ahead of estimates, but outlook is what's in focus today.  

Full-year earnings guidance was lowered to $0.33-$0.43 per share from a previous range of $0.40-$0.50 per share and below estimates of $0.44.

Now what: Management says that unscheduled outages, lower than expected steam demand, and slower organic growth have resulted in the lower guidance. But keep in mind that the company begins a contract in New York in 2015, something management is already preparing for. The rest of this year and 2014 will be a challenge, but the long-term thesis is intact and Covanta has the opportunity to be a great buy if it can execute its strategy into 2015.

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.