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 (NYSE: AMD) slumped nearly 17% in early trading today on more than double the average volume. Last night, the semiconductor supplier cut its third-quarter revenue forecast.

So what: Management now expects revenue to grow 4% to 6% in Q3, down from earlier estimates of 8% to 12%. AMD said that issues with manufacturing chips at 32 nanometers via its main supplier, Globalfoundries, cut into supply and thereby reduced its short-term revenue opportunity.

Now what: Interestingly, AMD isn't the only chip supplier to reduce guidance recently. Texas Instruments (NYSE: TXN) disappointed analysts in June when Nokia (NYSE: NOK) came in light on its orders for TI chips. So while the news from AMD isn't good, it's better to be short on supply than begging for demand. Do you agree? Would you buy AMD's stock at these levels? Please weigh in using the comments box below.

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