Amazon founder Jeff Bezos is now worth $US150 billion ($NZ220 billion), according to the Bloomberg Billionaire Index.
Amazon founder Jeff Bezos also briefly topped the world's rich list in July 2017. Photo: (TOMMASO BODDI AFP)
Jeff Bezos's net worth has increased by more than $60bn in the last 12 months, which makes him the world's richest man.
This places his worth higher than that of Microsoft co-founder Bill Gates, who has previously topped the rich lists - even at his peak in 1999.
Then Mr Gates was worth $100b - which would be around $149b today, when adjusted for inflation.
Mr Gates is currently in second place with a worth of $95b, having given away 700 million Microsoft shares and $2.9b in cash since 1996.
He gave the cash and assets to the Bill and Melinda Gates Foundation, Bloomberg reported.
Mr Bezos said he was selling about $1b of Amazon stock every year to fund Blue Origin, the project he has founded to develop commercial space travel.
It's not the first time Mr Bezos has topped the world's rich list - in July 2017, he briefly overtook Mr Gates to become the world's richest man according to Forbes when Amazon's shares surged - but returned to second place when their value dropped again.
The news of Mr Bezos's wealth came as Amazon prepared for its enormous Prime Day sale on 16 July, which was marred in Europe by worker strikes in Germany, Spain and Poland over working conditions.
"The message is clear - while the online giant gets rich, it is saving money on the health of its workers," said Stefanie Nutzenberger of Germany's Verdi services union.
Amazon said its workers were paid fairly, with permanent staff earning €12.22 ($NZ21.00) an hour or more after two years.
Meanwhile two of Amazon's rivals, Microsoft and Walmart, are set to announce a five-year deal which will see the retailer use the tech giant's cloud computing technology, according to the Wall Street Journal.
