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 solar-product maker SunEdison (NYSE: SUNE) dropped as much as 29% today after the company reported earnings.

So what: Second-quarter revenue fell 39% to $491.6 million and the company lost $0.19 per share. That compares to estimates of $443.3 million in revenue and a $0.13 loss so the results were mixed based on Wall Street's expectations.  

Now what: This is part of a broader solar sell-off today but it does show weakness in SunEdison's business. The company is still supplying a commodity product to the industry so, until prices improve, investors shouldn't expect higher profits. I'd stay away from this stock for now but watch for improvement in demand, and keep an eye on margins in the systems business, because that's really where the company sees its future.

Interested in more info on SunEdison? Add it to your watchlist by clicking here.

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.