The magazine said its real-time tracking of personal fortunes showed Bezos with a net worth of $90.5 billion, ahead of the $90 billion for Gates.
Bezos owns around 17% of the equity of Amazon, which has been expanding from its original mission as an online retailer to a diversified tech firm in cloud computing, online video, computing hardware and artificial intelligence.
The company also recently announced plans to acquire US grocer Whole Foods, which could help Amazon expand in that sector.
Amazon shares were up 1.7% at $1,070.72 and have risen some 24% over the past four months, adding some $17 billion to the net worth of the 53-year-old Bezos.
According to Forbes, Gates has been the richest person in the magazine’s annual rankings in March for the past four years and 18 of the past 22 years. Mexican telecom magnate Carlos Slim overtook Gates from 2010 to 2013.
Among the billionaires gaining ground is Facebook founder Mark Zuckerberg, who has an estimated worth of some $72.9 billion.
While most of Bezos’s wealth is in Amazon, he also owns the private space firm Blue Origin and the Washington Post newspaper.