Bitmain

In 2013, Micree Zhan and Jihan Wu founded Bitmain. Headquartered in Beijing, the company produces ASIC chips, or hardware optimized for Bitcoin's cryptographic algorithms. The chips quickly became a favorite among Bitcoin miners, and by the time of Bitmain's attempted 2018 IPO, it was one of the world's most prominent crypto companies. 

The IPO did not come to pass, but Bitmain is still one of a small handful of Chinese firms that control a large majority of the Bitcoin mining market. Its Bitcoin mining pool, which combines the computational power from several miners to get a better shot at successfully mining Bitcoin, is also among the world's largest. Recently, the company has come under scrutiny from Congress for its ties to China.