According to the “Bitcoin Mining The Evolution of A Multibillion Dollar Industry” research published by Yassine Elmandjra and Derek Hsue from ARK Invest the BTC mining industry is surprisingly competitive.
Authors have assessed the level of mining pool centralization with the Herfindahl-Hirschman Index (HHI), a common heuristic for determining market concentration. “The U.S. Department of Justice considers a market with an HHI of less than 1,500 to be a competitive marketplace, an HHI of 1,500 to 2,500 to be a moderately concentrated marketplace, and an HHI of 2,500 or greater to be a highly concentrated marketplace”
According to the calculation, the HHI for mining pools has improved over time, with the only instance of concentration in 2013. Since then, the HHI has declined on average in every year and currently stands at 1,300-1500.
Moreover, to address Bitcoin critics claim that Bitmain controls most of BTCmining, Authors of the research have also calculated a version of the HHI that accounts for Bitmain’s influence over BTC.com, F2Pool, and 50% of ViaBtc, so much so that they are considered as a single entity. Under this assumption, the HHI peaked in 2018 at ~2050, and has declined since, and still suggests that the mining pool industry currently is still competitive.