Bitcoin surged to nearly $42,000 around January 7, but has since endured a bruising week and is down to around $31,000, although this is still far above its previous highs.
Warning signals over the bubble have been picked up by investors, according to Deutsche Bank. A survey of investors found 90pc believed stock markets were in bubble territory, with Bitcoin top of their concerns.
There has been a recent push of institutional money into cryptocurrencies. Square, the payments company founded by Jack Dorsey, bought $50m of Bitcoin in October (which are now worth around $150m). UK investment fund Ruffer said in December it was buying £550m of Bitcoin.
Of course, this means that digital coin believers argue the price is only on the way up, due to the scarcity of its supply.
Peter Wall, of cryptocurrency mining company Argo Blockchain, says: “We believe in Bitcoin. It is the reserve asset of today and tomorrow.”
Saylor, on a recent Bloomberg podcast, gives Bitcoin a religious significance. He says: “If God had intended gold as a treasury reserve asset to hold for 100 years he would have made 21 million gold coins and made it impossible to make any more.” Saylor did not respond to a request for comment.
Regulators, however, are not won over. The Financial Conduct Authority warned earlier this month that amateur investors should be prepared to “lose all their money”.
Due to the nature of Bitcoin transactions – they are recorded on a verifiable digital ledger – it is possible to see many of the biggest transactions play out in real time and to identify digital wallets.
The single largest Bitcoin stash holds 1m Bitcoin or $30bn. It is said to be the first Bitcoin wallet and is believed to have been the one used by its creator, Satoshi Nakamoto. It has remained dormant for several years amid speculation its creator is dead.
Other accounts are those of crypto exchanges. A wallet belonging to the Huboi exchange holds $4bn in Bitcoin, for instance.
Some big Bitcoin whales are more bizarre. The Government of Bulgaria is said to hold almost $6bn worth of Bitcoin that was seized in a raid. A mysterious account, thought to be the leftover cryptocurrency from the Silk Road dark web drug market, is worth about $1bn.