Amazon shares jumped 2.5 percent at the start of trading on Thursday, boosting the net worth of Bezos - the company's founder and largest shareholder - by $1.4 billion, said Forbes, which tracks the world's wealthiest, reported Reuters.
The stock was up ahead of Amazon's second-quarter earnings report after Thursday's market close.
However, Microsoft co-founder Gates dethroned Bezos in no time after Amazon shares dropped, reported BBC.
Bezos was also in the second place right behind Gates in the list of world's richest person published by Forbes in March.
Bezos, 53, a relative newcomer to the top of Forbes' list who owns 17 percent shares of $500 billion Amazon, has benefited from the seemingly boundless expansion of Amazon into new markets.
Reuters could not independently verify the wealth of Bezos or Microsoft Corp's co-founder Gates.
A philanthropist, Gates has given $31.1 billion to charitable causes through 2016 and has a net worth of $90.1 billion, Forbes said.