A 1 percent pop 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 now estimates the wealth of Mr. Bezos, currently Amazon’s chief executive, at about $90.6 billion, compared with $90 billion for Mr. Gates.
Mr. Bezos has added tens of billions of dollars in wealth — at least on paper — over the last year as Amazon shares surged more than 40 percent during that time period. They traded at about $1,063 on Thursday, ahead of the release of the company’s latest earnings report.
According to a filing with securities regulators in April, Mr. Bezos holds nearly 81 million shares of Amazon — almost 17 percent of the company. Forbes also estimates the value of his other investments — including his ownership of The Washington Post and the rocket company Blue Origin — and cash from the sale of securities as part of its wealth calculations. Mr. Bezos has said he sells about $1 billion a year worth of Amazon stock to finance Blue Origin.
Mr. Gates has been at the top of the Forbes list of billionaires for 18 out of the last 23 years.
Most of Mr. Gates’s wealth originates from Microsoft, which has seen its stock rise to new highs lately. A Microsoft filing from last October said he held nearly 191 million shares of Microsoft — about 2.46 percent of its stock — which are currently worth about $14.1 billion.
But Mr. Gates has spent years diversifying his investments.
Kerry Dolan, an assistant managing editor for Forbes, said the publication also considers extensive assets Mr. Gates holds through his Cascade Investments, which has stakes in private equity, real estate and public companies. Forbes does not include his more than $31 billion in contributions to the Bill & Melinda Gates Foundation in its wealth calculations.