According to chain.info, an estimated 10,6% of
Bitcoin's circulating supply, representing 1,96 million BTC is held by only five exchanges.
The list includes companies Coinbase, Binance, Huobi, OKEx and Kraken. Probably thanks to its custody solution Coinbase stores most Bitcoin. Below a list of holdings per exchange:
1. Coinbase - 944.904 BTC
2. Huobi - 323.665 BTC
3. Binance - 289.961 BTC
4. OKEx - 276.184 BTC
5. Kraken - 126.510 BTC
The 10,6% is based on the current circulating supply of
Bitcoin. However, blockchain analysis firm Chainalysis estimates that around 3.7 million BTC have been lost over the years. For example, people losing their private keys and thus losing access to their BTC. If this estimation is accurate, the percentage would be more likely to be around 15%.
The following seven exchanges based on most extensive BTC holdings, manage some 210.000 BTC together.
Coinmerce recommends storing larger amounts of cryptocurrency on personal hardware wallets. However, be aware, this means you are fully responsible for the security of your funds, you are truly your own bank.