Tencent Holdings Ltd. added to Friday’s sharp decline to start the week, putting the stock’s two-day loss of market value at $66 billion following America’s move to ban residents from doing business with the company’s WeChat app.

The stock fell 4.8% Monday and nearly reached Friday’s low. The cumulative 9.6% drop, the worst two days since October 2011, followed a four-month, 70% surge which put shares into record territory and made the internet giant Asia’s most valuable company at nearly $700 billion.

Tech stocks in Hong Kong led declines in the city Monday, with the Hang Seng Tech Index falling as much as 3.6%. The sector was also among the weakest performers in China, with the ChiNext Index dropping as much as 2%. Suppliers to Apple Inc. saw some of the biggest declines.

Deteriorating relations between the U.S. and China are raising investor concerns about the geopolitical impact on economies and markets. In addition to the the WeChat ban, Trump signed an order to prevent U.S. residents from doing business with ByteDance Ltd.’s TikTok app starting in six weeks.