A surge in Amazon.com Inc. shares Thursday morning in advance of the online retailer’s earnings report has propelled founder Jeff Bezos past Bill Gates as the world’s richest person.

Shares of the online retailer rose 1.8 percent to $1,071.31 as of 9:30 a.m. in New York. If the gains hold through the close, Bezos, 53, could leapfrog Gates on the Bloomberg Billionaires Index. The 61-year-old Microsoft Corp. co-founder has held the top spot since May 2013.

Investors and analysts, in addition to watching Amazon’s progress in taking market share in categories such as apparel and groceries, will be scrutinizing how many new subscriptions the retailer sold for its $99-a-year Amazon Prime service, which offers delivery discounts and video and music streaming. Prime shoppers spend more than customers who don’t have a membership.

“Amazon Prime is why so much physical retail is going away,” said Michael Pachter, a Wedbush Securities Inc. analyst who has a buy rating on the stock and a price target of $1,250. “Anyone who joins Prime shops in retail stores 10 percent less, and that number will keep accelerating as Amazon adds more inventory.”

Investors also monitor Amazon’s cloud-computing division, Amazon Web Services, a fast-growing and profitable business that accounts for about 10 percent of revenue. Amazon leads the cloud-computing industry, but faces increasing competition from Microsoft and Google parent Alphabet Inc.

Bezos owns about 17 percent of Seattle-based Amazon, which has surged 40 percent this year through Wednesday, helping to add $24.5 billion to his net worth. He started 2017 as the world’s fourth-wealthiest person and has since leapfrogged Inditex SA founder Amancio Ortega, who ranks third with $82.7 billion, and Berkshire Hathaway Inc.’s Warren Buffett, No. 4, at $74.5 billion.