Jeff Bezos has had more than $21 billion ($NZ32.5b) wiped off his net worth after Amazon's shares suffered their biggest fall since 2014.
The online retail behemoth fell by more than 13 per cent on Friday as investors reacted to the company posting its weakest growth in two decades and warning of a further slowdown.
The drop knocked more than $178b off Amazon's value as shares fell to their lowest level for almost two years.
Bezos, Amazon's founder and executive chairman, has a 9.8 per cent stake in the company, that makes him the world's second richest man after Elon Musk.
Friday's fall means he has now lost about $40b this year, leaving him with a fortune of $152b.