The claims were first made in 2017. in a study by academics John Griffin and Amin Shams following the surge in interest in Bitcoin, where one unit of the cryptocurrency was worth $20,000.

Mr. Griffin and Mr. Shams are now doubling down on their earlier claims, saying the manipulation was caused by a single participant using stablecoin Tether, a cryptocurrency designed to be worth $1.00 and allegedly is always backed by equivalent assets – until artificially increasing the price of Bitcoin.

“By mapping the bitcoin and tether blockchains, we can identify that a major player on Bitfinex is using tether to buy large amounts of bitcoin when prices fall and after tether is printed,” Mr. Griffin and Mr. Shams wrote in the study.

"Such price support activities are successful as bitcoin prices rise after the intervention periods."

The report claims that the stablecoins used to buy bitcoins were not actually backed. This has been a point of contention for tether for some time, with the company repeatedly failing to deliver on promises to audit its assets.

However, Tether – along with a number of industry figures and experts – denied the report's claims.

"Tether and its affiliates have never used tether tokens or issues to manipulate the cryptocurrency market or token pricing," the company wrote in a statement to bitcoin exchange Bitfinex.

“All tether tokens are fully backed by reserves and are issued in accordance with market demand, not to control the pricing of crypto assets. It is reckless – and completely false – to claim that tether tokens are issued to enable illegal activity.”

Jeremy Aller, CEO of Circle, a peer-to-peer crypto payments company, wrote that the study was flawed and refuted the claim that a single person could be responsible for manipulating the price of Bitcoin.

"Exchanges use omnibus wallets that aggregate all customer balances and transactions on and off the exchange," Mr Allaire wrote on Twitter.

“So an analysis showing that a 'single wallet' was involved in the flows from Bitfinex to other exchanges is meaningless. All it shows is that the traders traded.

The report also does not take into account a number of other factors associated with the increased price of Bitcoin, including an explosion in public interest in which a large number of speculators bought the cryptocurrency.