Bitcoin has climbed back above US$40,000 after two days of solid growth in response to a tweet from Tesla CEO Elon Musk.
Over the weekend the billionaire told his followers the electric car manufacturer would reconsider accepting the cryptocurrency as a payment option once "reasonable clean energy" was used by miners.
He also said the electric car company had sold off around 10 percent of its bitcoin holdings in an attempt to prove it could be liquidated without influencing the market.
That prompted a 10 percent jump on Sunday, US time, followed by a further 4.3 percent on Monday - the first time it's gone above the US$40,000 mark in over two weeks.
"Musk's words caused bitcoin to surge," Simon Peters, market analyst at eToro, told Reuters.
Musk has long been a supporter of cryptocurrencies and recently indicated that he supported it over more traditional fiat currencies.
Tesla purchased US$1.5 billion of the popular cryptocurrency in February, announcing it would accept it as payment at the time.
However the company backtracked in May, suspending the option because of the "rapidly increasing use of fossil fuels for bitcoin mining and transactions".
But his tweets around bitcoin and his support of meme-based alternative dogecoin have caused a backlash, with the belief his public pronouncements are impacting the price.
Just last week hacking group Anonymous took aim at Musk for his cryptocurrency tweets, calling him just "another narcissistic rich dude who is desperate for attention".
"Reading the comments on your Twitter posts it seems the games you have played with the crypto markets have destroyed lives," they said.
"Millions of retail investors were really counting on their crypto gains to improve their lives. Your tweets this week show a clear disregard for the average working person."
