Jeff Bezos’s net worth reached $105.1 billion Monday on the Bloomberg Billionaires Index as Amazon.com Inc. shares added to a 12-month surge that’s lifted the online shopping giant’s market value by almost 57 percent.

Amazon shares have risen 6.6 percent this year, with a report showing the Seattle-based company captured 89 percent of online spending among dominant holiday retailers in the five-week period beginning the day after Thanksgiving in the U.S.

The latest jump has pushed Mr Bezos’s fortune definitively above the high reached by Microsoft’s Bill Gates in 1999. The Amazon founder passed Mr Gates in October with a net worth of $93.8 billion and his fortune crossed $100 billion for the first time a month later when the holiday shopping season kicked off on Black Friday.

Mr Gates, 62, would have a net worth of more than $150 billion if he’d held onto assets that he’s given away, largely to the Bill & Melinda Gates Foundation. He 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.

Mr Bezos also controls closely held space exploration business Blue Origin and the Washington Post.