Tesla and SpaceX founder Elon Musk has added US$100 billion to his fortune since the start of the year, rocketing into second-place on the world's rich list.
Musk, now worth US$128 billion, overtook Facebook founder Mark Zuckerberg last week to move into third, and has now overtaken former Microsoft boss Bill Gates in second place on Bloomberg's Billionaires Index.
Only Amazon founder Jeff Bezos, with US$182 billion, is richer.
Most of Musk's wealth is tied up in his car company Tesla, whose stock price has surged this year. In January, Musk was ranked 35th. Since then Tesla's share price has jumped from US$83 to US$555.
Bloomberg said Gates would remain number two if he hadn't given so much of his wealth away - about $50 billion since setting up the Bill and Melinda Gates Foundation in 2006.
Bezos has added US$67 billion to his net wealth this year.
Musk has a chance of overtaking him soon - if he can get Tesla's total market capitalisation to US$650 billion by 2028, he's eligible for a whopping US$55.8 billion bonus.
Tesla makes only a fraction the number of cars of other big automakers like Toyota, but is expected to be the beneficiary of moves towards all-electric vehicles in the coming years.
Bezos' and Musk's good fortune has come at a time when many are out of work thanks to a global recession expected to be the worst since World War II.
The only person on Bloomberg's Billionaires Index from New Zealand is Graeme Hart. He's in 171st place with US$11.4 billion, up a whopping $4.3 billion this year alone. German-American tech billionaire Peter Theil, a New Zealand citizen despite never having lived here, is 372nd with $6.2 billion.
