WASHINGTON-Jeff Bezos broke the $100 billion mark for the first time on Friday - one month after he officially became the richest man in the world.

Bezos, 53, had flirted with the top spot earlier in the year but inconsistent shares meant he didn't push past Bill Gates to claim the crown properly until October, when he reached $90 billion.

Now he's topped even that, making $100.3 billion off the back of pre-Black Friday excitement over Amazon's discounts, Bloomberg reported.

In total, Bezos' worth shot up $2.4 billion, continuing a phenomenally successful year for the digital mogul, who started the year at around $65 billion.

The total had dipped slightly to $97.9 billion as of 3pm, but it remains a notable day for the Amazon founder, who has never before broken through the $100 billion threshold.

He also remains well ahead of Microsoft's Bill Gates, who is on $88.9 billion, and third-place financial whiz Warren Buffett, who is worth $78.9 billion.

Amazon shares climbed 5 per cent just this week, as the tech giant continues to expand its footprint in the US to accommodate the public's growing reliance in online shopping.

The National Retail Federation announced recently that, for the first time, more people are shopping online than in stores this year.

And the amount of money expected to be spent is around $1,000 per person - a record high, and an increase of 3.4 per cent on last year's figures.

That's certainly helping Amazon, and its founder.

Of course, with Bezos' continued rise, questions are being asked about what he plans to do with his extraordinary wealth.

Bezos has given away considerably less than Buffett and Gates - the latter of whom, Bloomberg noted, would be worth $150 billion if he'd kept his fortune to himself.

Instead, he has given away more than 700 million Microsoft shares and $2.9 billion in cash. Bezos, meanwhile, has given away around $500 million in Amazon shares since 2002. He sells $1 billion of Amazon stock every year to fund Blue Origin, his space business.

However, he has shown an interest in spreading his money further, and in June he asked Twitter followers for suggestions on how he could donate his wealth.