A third of the bitcoins in circulation are stored in a small number of wallets, and half of the hashrate is provided by 50 mining entities, a new research reveals.
The latest report from the National Bureau of Economic Research claims that 10,000 investors hold about a third of the issued bitcoins, or 8.5 million BTC. Of these, 1,000 investors own about 3,000,000 bitcoins. Another 5.5 million BTC is in the hands of intermediary services such as centralized exchanges or hot wallets.
The concentration of bitcoins in the hands of whales may be even higher, the researchers note.
“This measurement of concentration most likely is an understatement since we cannot rule out that some of the largest addresses are controlled by the same entity,” researchers Igor Makarov and Antoinette Schoar wrote.
The concentration of miners' power in the bitcoin network is even higher. About 10% of miners control 90% of the mining capacity of the network. Of these, the 50 largest miners account for a whopping 50% of mining capacity. This high concentration could leave the bitcoin network vulnerable to a 51% attack, where a group of miners by prior conspiracy can take control of most of the network. NBER founds that the concentration decreases when BTC price is growing, and, on the contrary, increases while bitcoin is falling.
“Our results suggest that despite the significant attention that bitcoin has received over the last few years, the bitcoin ecosystem is still dominated by large and concentrated players, be it large miners, bitcoin holders or exchanges,” the researchers wrote. “This inherent concentration makes bitcoin susceptible to systemic risk and also implies that the majority of the gains from further adoption are likely to fall disproportionately to a small set of participants.”