The 50 richest people on the planet have total wealth of $US1.45 trillion – which is more than the total GDP of Australia, Spain or Mexico.

The figures come from research by Wealth-X and Business Insider website and the names of the global uber-wealthy are by and large not a surprise.

What is surprising is that more than two-thirds of the list are completely self-made. The tech sector is where the big bucks are, with nearly a quarter of the list coming from that sector.

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Microsoft founder Bill Gates topped the list with his fortune now sitting at $US87.4 billion. Not only is Mr Gates the richest man in the world, but, with wife, Melinda, he’s also the most generous.

The couple’s Bill & Melinda Gates Foundation is a $US40 billion philanthropic powerhouse which aims at eliminating infectious disease in the developing world.

Only four women have made the top 50.

The oldest, 93 year old L’Oreal heiress, Liliane Bettencourt, is number 17 with $US29 billion.

After Mr Gates came Spanish fashion retail mogul and Zara founder, Amancio Ortega Gaona, with a $US66.8 billion fortune built on his stylish house brand clothing and shoes.

Following him came modest Berkshire Hathaway investment group chief, Warren Buffett, with $US60.8 billion. Mr Buffett has lived in the same suburban home in Omaha, Nebraska, for over four decades.

Amazon founder Jeff Bezos is next with $US56.6 billion.

His online book sales business has branched out into new areas including bricks and mortar book stores, media through his purchase of the Washington Post and even space travel.

Liliane Bettencourt is the oldest on the rich list. Photo: AAP

Right wing Republican brothers David Koch and Charles Koch, who run the diversified Koch Industries group, are worth around $US47 billion each and follow Mr Bezos on the list.

Facebook co-founder, Mark Zuckerberg, came in at number eight with $US42.8 billion. He’s the youngest on the list at 31.

Pipping him at number seven is Oracle software group founder, Larry Ellison, with $US45.3 billion.

Number nine is media entrepreneur and politician, Michael Bloomberg, at $US42.1 billion and at number 10 is Swedish retail tycoon, Ingvar Kamprad, with $US39.3 billion.

Apple founder Steve Jobs’ widow, Laurene Powell Jobs, was equal 47th with $US14.4 billion.

The United States is home to the most billionaires with 29 listed.

China comes in second, with four billionaires, and India is third, with three billionaires.