Bitcoin surges above $47,000

Bitcoin, the infamously volatile cryptocurrency, has surged to its most expensive levels ever, thanks to the world's richest man.

Bitcoin was above $47,000 ($60,949) by 11:45 am on Tuesday morning, after Elon Musk's electric vehicle company, Tesla, said it had invested $US1.5 billion into the digital currency.

Tesla also revealed that it plans to accept bitcoins as a form of payment soon — the biggest vote of confidence the crypto market has received yet.

At current prices, it would cost around 0.88 bitcoins to purchase an entry-level Tesla Model 3.

However, Tesla did not reveal how many bitcoins it purchased and at what price.

Bitcoin's price has fluctuated wildly (anywhere between $29,000 and $40,000).

Tesla's decision sparked euphoria across the broader digital currency market, with the second-largest crypto (ethereum) also jumping to a record high, above $1,700.

But the incredible thing was that Telsa didn't even make a grand announcement about it.

Eagle-eyed investors found out about the company's bet on cryptocurrencies buried on page 106 of Tesla's annual report (it was under the obscure heading "Note 23 - Subsequent Events").

The bitcoin price was sitting around $US39,000 on Monday evening (Australian time), just before the US Securities and Exchange Commission (SEC) published Tesla's report online. So in just 12 hours, bitcoin's value has soared by around $US8,000.