Bitcoin mining pools controlled by China-based industry giant Bitmain presently controls over 40 percent of the overall Bitcoin hashrate, triggering new concerns regarding miner centralization.
Data from Coinbase states that bitcoin mining pools BTC.com and Antpool have mined 25.5 percent and 16.5 percent, respectively, of the total number of bitcoins in the past week.
Bitmain owns both of these mining pools which implies that the firm presently controls more than 42 percent of the bitcoin hashrate. The two pools also control a joint 21.3 percent of the Bitcoin Cash hashrate, which runs on the same algorithm as bitcoin.
At this point, Bitmain is very close to controlling 51 percent of the Bitcoin hashrate, a level that could allow it to wage a 51 percent attack against the network. Recently, such attacks have been effectively used against a list of smaller altcoins, such as Litecoin Cash, Bitcoin Gold, Verge, Litecoin Cash and Monacoin.
There is smaller financial gain from attacking Bitcoin, but some in the community are concerned that Bitmain could release a malicious attack against the network nevertheless. This is not a very possible situation but critics argue that a talk by all means that bitcoin is too centralized.
It is still uncertain on the percentage of the hashrate owned by devices physically controlled by Bitmain, but that point is somehow arguable given that pool operators control the block templates for the entire pool.