Jeff Bezos is on track to claim his place as the richest person on the planet.

Amazon.com Inc. shares surged at the open of U.S. markets Friday, lifting its founder’s net worth by $6.6 billion to $90.2 billion, according to the Bloomberg Billionaires Index. The stock climbed 8.6 percent to $1,056 at 9:31 a.m. in New York, a day after the retailer reported results that beat Wall Street estimates. If the share gains hold through the trading session, Bezos will top the index for the first time.

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

Gates ended Thursday with a net worth of $88 billion, $4.5 billion ahead of Bezos on the Bloomberg index, a daily ranking of the world’s 500 richest people. Gates, 61, has been the world’s richest person since 2013.

Bezos, 53, has added $18.1 billion to his fortune this year. Gates’s net worth rose by $5.6 billion, even after he  donated $4.6 billion of Microsoft stock to the Bill & Melinda Gates Foundation in August.

Gates has given away almost 700 million Microsoft shares and $2.9 billion of cash and other assets since 1996, according to an analysis of his publicly disclosed giving. He would be worth about $150 billion if he hadn’t made the donations.

This article was provided by Bloomberg News.