These online brokers are engaged in “illegal financial activities” because they have no “driving licenses” to operate in China, Sun Tianqi, a senior People’s Bank of China official wrote in an article published on the website of Finance 40 Forum. Sun didn’t name the brokers, and added that calling them illegal has nothing to do China’s capital control rules.

https://www.bloomberg.com/news/articles/2021-10-28/china-trading-apps-tank-after-pboc-official-calls-them-illegal?sref=EcccZSTc