Bezos' ascent is the first time anyone has crossed the $100 billion threshold since Microsoft co-founder Bill Gates earned it in 1999, according to Bloomberg, whose Billionaire's Index follows the real-time net worth of the world's 500 wealthiest people.

Amazon shares were up 2.5 per cent to US$1,186 at Friday's 1pm market close. Stock exchanges closed early Friday because of the Thanksgiving holiday weekend. Amazon shares are up more than 58 per cent this year, consequently boosting Bezos's wealth with it.

Amazon's upward arc followed Friday's broad market push that saw the S&P 500 Stock Market Index reach another record at 2602, the first time it has closed above 2,600.

The Dow Jones industrial average rose 32 points to 23,557.99, and the tech-heavy Nasdaq Composite closed higher at 6,889.

Markets are approaching the end of 2017 fuelled by robust earnings, a rare harmony among growing world economies and bullishness over possible US tax reform.

Bezos, 53, is the owner of The Washington Post.

His wealth, largely based on his Amazon holdings, began the year around $65 billion.

It has steadily risen with the rising stock market and the surge in Amazon shares, which rose 5 percent this past week as the nation's busiest shopping season picked up steam with its traditional Thanksgiving launch.

Amazon has been on a tear this year. In addition to buying high-end grocery chain Whole Foods, the retailer has been conducting a highly-publicised search for a second North American headquarters.

The search has drawn 200 proposals from across the continent because of the company's potential to impact regional economies.

The company's perceived ability to disrupt industries from entertainment to groceries to traditional retail once prompted media mogul John Malone to refer to Amazon as the "Death Star."

Bezos is the largest owner of Amazon shares, and earlier this year he said he sold about $1 billion of his stock every year to fund his ambitious Blue Origin spacecraft company.

Gates is the second wealthiest man on Bloomberg's index with a net worth of approximately $88.9 billion. Investor Warren Buffett is third at around $78.9 billion.

Washington Post

The story, Black Friday just made Jeff Bezos the world's only US$100-billionaire, first appeared on the Sydney Morning Herald.