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 Advanced Micro Devices (NASDAQ:AMD) have plunged today by as much as 17% after the company reported earnings last night.

So what: Revenue in the second quarter totaled $1.16 billion, which translated into an adjusted loss of $0.09 per share. Both figures were ahead of Street forecasts, which called for $1.11 billion in sales, and a loss of $0.13 per share. The real cause for concern was within guidance.

Now what: The third quarter should see revenue increase sequentially by approximately 22%, which is a healthy figure. Despite the expected top line gains, investors are concerned about profitability. AMD said gross margin next quarter should be around 36%, a significant sequential drop from the 40% gross margin just posted. Shares have already soared in recent months on optimism around next-generation game consoles, but the custom chip business is proving to be less profitable than investors were hoping for.

Interested in more info on Advanced Micro Devices? Add it to your watchlist by clicking here.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.