Bitcoin and its rivals fell on Friday as world leaders and other notable figures from investment and academia used their platforms at the World Economic Forum at Davos to express caution on cryptocurrencies.
Meanwhile, an unhelpful development for investors in crypto-assets came to light on Friday as it emerged Bitconnect - the self-styled crypto community platform that provides multiple investment opportunities - was being sued for operating a Ponzi scheme.
News of the class action from six individuals who collectively invested $771,000 in Bitconnect led to a loss of 90% in the value of Bitconnect tokens last week. On Friday, Bitconnect was presented with the lawsuit, accused of "aggressively recruiting new investors" using social media.
Such events have led to speculation that tighter regulation will be enforced on crytpocurrency exchanges around the world, and even that bitcoin and its rivals could face closer scrutiny from regulators.
Indeed, it has been a hot topic at Davos this week, with UK prime minister Theresa May saying: "I think it's something we should look at."
Philip Hammond, UK chancellor of the exchequer, added: "I think we should be cautious about Bitcoin and possibly we do need to look at the way we regulate this environment."
International Monetary Fund chief Christine Lagarde weighed in on the topic, concerned over the lack of transparency in cryptocurrency trade.
She said: "It conceals and protects money-laundering and financing of terrorism and all sorts of dark trades. This is just not acceptable."
And on Thursday afternoon, the Davos agenda turned to a debate entitled: The Crypto-Asset Bubble. Eminent investors and Yale academic, Professor Robert J Shiller, discussed the impact of bitcoin.
Shiller noted: "Bitcoin is a really clever idea with incredible technology - but while the currency has gone viral, it's not stable."
He added: "The enthusiasm I see is more speculative than investment led and to that extent it is a bubble."
Suspicion nearly all round at Davos, and news that the very cryptocurrency exchanges that are facing tighter regulation are being accused of dealing in illegal activities, clouds the issue further.
Not surprising then, that the cryptocurrencies listed on the Bitstamp exchange were all lower on Friday.
- Bitcoin fell 6.23% to $10,488
- Ethereum lost 4.64% to $1,000.10
- Ripple fell 13.86% to $1.149
- Litecoin shed 6.08% to $168.34