Data from blockchain research company Chainalysis showed in April there were 1,600 bitcoin wallets held by investors, all of which contained 1,000 of the alt-coin each.
The unidentified ‘whales’ scooped an eye-watering 5million bitcoins between them, which amassed to a third of the market, according to the FT.
Just under 100 wallets contained between 10,000 and 100,000 bitcoin which would be valued at between $75million and $750million at today’s prices.
Chainalysis chief economist Phillip Gladwell said: “This concentration of wealth means that bitcoin is at risk of volatility as the moves of a small number of people will have a large price effect.”
Bitcoin is the most popular cryptocurrency and enjoyed a dramatic rise to the top last year when its price rose by 1,000 percent and its value peaked at $20,000 in the run-up to Christmas.
But since then, its trade price has fallen back down to $7,500 as regulators circle the sector and competitors Litecoin, Ripple and Ethereum flood the market.
Chainalysis data estimated long-term bitcoin holders sold off $30billion of the digital currency between December 2017 and April 2018, with half of trading taking place last December alone.
Mr Gladwell said: “This was an exceptional transfer of wealth, and conditions for it to occur again are unlikely to form again soon.”
Bitcoin is a cryptocurrency and worldwide payment system and was the first decentralised digital currency.
It was launched in 2009 by founder Satoshi Nakamoto.
The system works without a central bank or single administrator meaning it is open to anybody and everybody.
Last November, the amount of bitcoin owned by those who held the currency for more than a year was around three times what was held by short-term investors who traded more recently.
But by April 2018 the 6million bitcoin possessed by long-term investors was closer to matching the amount held by short-term spectators, with 5.1millin bitcoin.