Elon Musk has beaten Microsoft co-founder Bill Gates to become the second richest person in the world as per the Bloomberg Billionaires Index. Musk’s net worth is now about $128 billion after it shot up by $100 billion this year.

It will take Musk a while to rise to the number one position on the list which is held by Amazon CEO Jeff Bezos. There is a sizable gap between Musk and Bezos who has reported a net worth of $182 billion. However, it has been a significant climb for the Tesla and SpaceX CEO who was at rank 35 in January this year.

Musk’s rapid ascent has mainly been driven by Tesla’s share price. The company currently has a market cap of almost $500 billion, after starting the year at under $100 billion.

According to a report in The Guardian, Tesla has the highest market cap of any car company in the world, despite producing a fraction of the cars as compared to more established automakers. This year Tesla expects to produce 500,000 cars as compared to around 10 million to be produced by company like Toyota. Around three quarters of Musk’s net worth consists of Tesla shares, according to Bloomberg.

Musk’s other major venture, SpaceX, has also seen success lately. Last week the SpaceX transported four astronauts to the International Space Station (ISS) aboard its Crew Dragon spacecraft. This came just after SpaceX’s first crewed flight to space in May this year.