Elon Musk is now the world’s richest person, completing one of the “most unlikely business stories of all time”, according to his biographer.

According to the Bloomberg Billionaire Index, the Tesla and SpaceX founder is now estimated worth $250 billion ($US194 billion), taking him past Amazon founder Jeff Bezos as the richest person in the world.

The maverick entrepreneur was worth an estimated $35 billion at the start of last year, but is now worth about $US1.5 billion more than Bezos.

Last year it was revealed that it would take the average Australian nearly five months to make as much as Musk does in just five minutes.

Musk’s rapid rise up the index is thanks to a hugely successful 2020 for Tesla, with shares in the company jumping by 760 per cent across last year.

Musk has a 20 per cent stake in Tesla which is now worth $178 billion ($US138 billion), along with a stake in SpaceX, which is still a private firm.

Tesla now has a market cap of $996 billion, making it the fifth most valuable company on Wall Street and the most valuable automotive manufacturing company in the world.

Tech stocks have also enjoyed popularity in the last 12 months during the ongoing COVID-19 pandemic.

Musk had a typically left-of-centre response to the news, posting on Twitter in reply to the announcement, “How strange”, followed by “Well, back to work”.

It’s a big turnaround for Musk, who has been embroiled in controversy in recent years.

In 2018, the US Securities and Exchange Commission sued Musk and Tesla over misleading statements he made on Twitter.

Musk stepped down as chairman of Tesla as part of the settlement, and also paid a $US20 million fine.

Musk was also recently criticised for questioning rapid antigen COVID-19 tests, with a reply labelling him as “Space Karen” going viral.

Author Ashlee Vance, who wrote Musk’s biography, said Musk’s story is one of a kind after the entrepreneur used money earned from the sale of PayPal to fund the creation of Tesla and SpaceX.

“How many people put in a similar position would take a personal fortune of $200 million and bet it all on solar, electric cars and rockets in 2001?” Vance tweeted. “I bet if you run the simulation again and again, it ends up with one.

“That he lost all the money and still ended up as the richest person – that Tesla and SpaceX survived the 2008 crash – has to be right up there with the most unlikely business stories of all time.

“Elon has had his ups and downs both in business and in personal terms, but it’s pretty clear that he is the biggest risk taker we’ve seen in our lifetimes.

“It still remains very interesting to see where Tesla and SpaceX end up. That said, as far as moments in time go, this is so far beyond surprising.”

Musk seemed to agree with this assessment, tweeting back a simple: “true”.

Following Tesla’s rise last year, Apple might be regretting its decision to not purchase the startup.

According to Musk, he tried to schedule a meeting with Apple CEO Tim Cook to sell Tesla to the tech giant, for a tenth of the price it is now worth, but was rejected.

It was also a strong 2020 for SpaceX, with the startup successfully launching NASA astronauts into orbit, making it the first private company to do so.

Musk is also involved with a number of smaller, stranger startups, including Neuralink, which last year put a prototype computer device in the brain of pigs to demonstrate its effectiveness.