Amazon shares have been hit by falling confidence in tech stocks and a slowdown in online shopping as consumers emerge from the pandemic.
Amazon said on Thursday night revenues had climbed by just 7 per cent in the first three months of the year, its most sluggish growth since October 2001.
The company also recorded its first quarterly loss since 2015 as it took a multibillion-dollar writedown on its stake in Rivian, the electric car company.
Profitability was also hit by rising inflation in wages, fuel prices and shipping costs.
Bezos' stake in Amazon makes up the vast majority of his net worth. His stake in space company Blue Origin and other investments make up the remainder.
Investors reacted most strongly to Amazon's forecast that revenues would climb by between 3 per cent and 7 per cent in the coming quarter, a further slowdown.
Bezos has put billions of his personal wealth into Blue Origin in an attempt to rival Elon Musk's SpaceX.
Musk surpassed Bezos as the world's richest man last year as his electric car company Tesla soared to a $1 trillion valuation.
Bezos has also pledged to put billions into a fund to work on projects battling climate change.