Apple investors are willing to overlook many things, but the health of the Chinese iPhone market isn’t one of them.

On news of a tanking Chinese stock market early today, Apple investors were running for the exits. Apple stock dove way below the $100 market for the first time this year — to $94.87.

Apple may be a little sensitive about China, too. Tim Cook this morning made a rare mid-quarter statement about the market in a note to CNBC markets expert Jim Cramer. It goes:

I can tell you that we have continued to experience strong growth for our business in China through July and August. Growth in iPhone activations has actually accelerated over the past few weeks, and we have had the best performance of the year for the App Store in China during the last 2 weeks.

Cook gave no actual numbers, but the little he did say was apparently enough. Apple stock has now bounced back to pre-crisis levels at around $107 at the time of this writing (1 p.m. EST Monday).

This isn’t the first time Cook has addressed fears about the Chinese market, and Apple’s dependence on hot iPhone sales there.

China’s stock market tanked back on July 6, too, remember, and sure enough Cook found himself reassuring investors after his company announced third quarter earnings July 21. Apple’s stock dropped 7 percent in after-hours trading that day, largely on worries over China.

Apple reported a decline in China iPhone sales of 21 percent from the previous quarter, but a 112 percent increase from the same quarter a year earlier.

During a conference call with analysts, Apple CEO Tim Cook said Apple will continue to put the “pedal to the metal” in China, and that Apple might feel some bumps in the road but in the long term China will be a large and growing revenue source.

Cook has good reason for saying so. Apple’s large-screened phones sell best in markets where mobile bandwidth is plentiful, and the Chinese mobile carriers are just now building their LTE networks.

As of the end of 2014, the number of mobile Internet users in China reached 557 million (an increase of 56.72 million for the year), making it the largest smartphone market in the world, according to the China Internet Network Information Center.

This means there will be fierce competition among companies like Apple, Samsung, Xiaomi, Huawei, and others for share in the emerging market. And there may be enough addressable market there to buoy up Apple’s iPhone’s sales for the foreseeable future.