Bitmain is the largest manufacturer company that produces Application Specific Integrated Circuit miners (ASIC), and it also controls some of the biggest mining pools on the Bitcoin network. The two companies BTC.com and Antpool have more than 40% control over bitcoin mining and these both are operated by Bitmain. Currently, there is a fear around the industry that bitcoin mining may be on the way of becoming centralized. If Bitmain somehow manages to get over half of the hash power dedicated to bitcoin mining, they will get the power to alter an older block and change transactions fraudulently.