Apple shares fell 2.9% on Thursday after reports that China will ban the use of iPhones in government agencies and companies.
Investors are worried about the ability of the world's most valuable public company to do business in the world's second-largest economy.
Apple lost an estimated $200 billion as soon as China announced future plans to ban iPhones.
China is the largest foreign market for Apple products, and sales in China represented about a fifth of total revenue last year. Apple does not disclose iPhone sales by country, but analysts at research firm TechInsights estimate that there were more iPhone sales in China than in the United States last quarter.
Apple also makes most of its iPhones in Chinese factories.
The decision to ban iPhones came as soon as the United States of America announced that it would investigate the smartphones of the Chinese company Huawei.
