Entrepreneur Elon Musk, the brain behind Tesla and SpaceX, has closed in on Amazon's Jeff Bezos to become the world's richest man. Musk's fortune zoomed to $181 billion on Wednesday as Tesla's shares surged by 2.8%, Bloomberg reported.

Also read: Tesla misses its annual sale target of 500,000 vehicles by just 450 units

He is the second wealthiest person in the world, after Bezos, who has been at the top of the Bloomberg Billionaire Index, since 2017. Amazon CEO's wealth is pegged at $184 billion.

2020 was extraordinary for Musk when he saw his wealth surge by $150 billion. Tesla's share price rose by a massive 743% last year.

Despite his massive gains, Musk has said he has little interest in material things and that he has few assets outside his stakes in Tesla and SpaceX.

In an interview with Axel Springer, the Tesla chief said the main purpose of his wealth is to accelerate humanity's evolution into a spacefaring civilization.

"I want to be able to contribute as much as possible to the city on Mars," Musk said in the interview. 

"That means just a lot of capital," he added.

Last year, the world's 500 richest people added a record $1.8 trillion to their combined wealth, thus registering an increase of 31%.

Also read: Not Mukesh Ambani, this Chinese businessman is now Asia's richest man

Just seven days to this year, there have been major rejigs to the index. Chinese businessman Zhong Shanshan, who was little known until recently, has unseated American business tycoon Warren Buffet to become the world's sixth-richest man.