A post-earnings surge in Amazon.com Inc. shares Friday pushed  Jeff Bezos to the top of the Bloomberg Billionaires Index for the first time, vaulting him ahead of Bill Gates who had held the top spot as the richest person on Earth for more than four years.

The founder and chief executive officer of the retail juggernaut added $10.4 billion to his net worth as Amazon shares rose 13 percent, the most in 2 1/2 years, a day after the company reported quarterly sales and profit that surpassed analysts’ estimates.

His wealth briefly eclipsed that of Gates, the Microsoft Corp. co-founder, on an intraday basis on July 27, but Amazon shares ended that day lower, leaving Bezos at No. 2.

At the close of U.S. markets Friday, Bezos had a net worth of $93.8 billion, $5.1 billion ahead of Gates on the Bloomberg index, a daily ranking of the world’s 500 richest people. Gates, 61, had been the world’s richest person since 2013.

Bezos, 53, has added $28.5 billion to his fortune this year. Gates’s net worth has climbed by $6.3 billion since year-end, even after he  donated $4.6 billion of Microsoft stock to the Bill & Melinda Gates Foundation in August.