What: Shares of mobile chip giant Qualcomm (QCOM 0.49%) dropped by 12% last month, according to S&P Capital IQ data. Investors weren't impressed with Qualcomm's fiscal third-quarter earnings release in July, shares had mostly recovered from the related dip. But considering Qualcomm's customer concentration within China, all of the macro fears that weighed on the broader market hit Qualcomm far worse.

So what: Last fiscal year, customers located in China accounted for a whopping 50% of Qualcomm's total revenue. If you include neighboring countries South Korea and Taiwan, that figure rises to 84% for fiscal 2014. That's unsurprising, as the majority of the world's smartphone OEMs and contract manufacturers are located in Asia, but that also means that any concerns about slowing economic activity in the region will affect Qualcomm disproportionately.

Now what: China has been a particularly troublesome region for Qualcomm in recent times. Not only did it have to settle an antitrust investigation with regulators around its pricing practices earlier this year, but the company has also long suspected that many smartphone vendors are underreporting their shipment volumes in an effort to avoid paying royalties. Meanwhile, speculation remains about how much pressure Intel is exerting on Qualcomm's iPhone modem spot. Intel has been trying to win back this spot for years, and at the very least it seems that the iPhone maker will be able to win some concessions from Qualcomm.