SEATTLE — Jeff Bezos on Thursday took something away from a billionaire neighbor in the Seattle area, Bill Gates — the mantle of world’s richest person.

A 1 percent pop early in the day in the shares of Amazon.com — the internet company Mr. Bezos founded, which accounts for the vast majority of his wealth — was enough to bump him over the wealth of Mr. Gates, the philanthropist and Microsoft co-founder, according to a real-time list of billionaires by Forbes.com, which has tallied the fortunes of the uber-rich for decades.

Forbes estimated the wealth of Mr. Bezos, currently Amazon’s chief executive, at $90.6 billion, compared with $90 billion for Mr. Gates. Later in the day, Amazon’s shares cooled slightly, allowing Mr. Gates to regain the top position. The back and forth could continue depending on the fluctuations in Amazon shares.