Jeff Bezos owns 18% of Amazon’s shares, which rose 2% in trading on Thursday. Forbes estimated his fortune to be $65.3bn (£49.5bn).
Amazon’s revenue beat analysts’ expectations, climbing 31% from last year to $30.4bn in the second quarter.
Profit for the e-commerce giant was $857m, compared with $92m in 2015.
According to Forbes estimates, Bezos’s fortune is only surpassed by Microsoft founder Bill Gates, worth $78bn (£59bn), and the $73.1bn (£55bn) fortune of Zara founder Amancio Ortega.
Amazon had developed a reputation for announcing little or no profit each quarter, but appeared to hit a turning point last year and has seen improving earnings since.
Amazon shares have spiked 50% since February.
Amazon’s Prime membership, which offers extra services including free shipping for an annual fee, saw impressive international growth.
In June, Amazon launched Prime in India to take advantage of the country’s large consumer market.
“It’s been a busy few months for Amazon around the world, and particularly in India – where we launched a new [Amazon Web Services] Region, introduced Prime with unlimited free shipping, and announced that Prime Video is coming soon, offering Prime members in India exclusive access to Amazon Original Series and Movies – including original content featuring top Indian creators and talent,” said Bezos.
Amazon has boosted Prime membership by improving its video streaming offerings, an area in which it competes with Netflix.
Prime Day, Amazon’s annual promotional shopping festival earlier this month, was the company’s largest ever sales day.
Amazon does not release figures for its Prime membership, but Consumer Intelligence Research Partners estimated US membership to be close to 63 million. Members spend an average of $1,200 a year, compared with $500 by non-members, according to the research firm.
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Amazon’s cloud computing unit also spiked. Revenue for Amazon Web Services (AWS), climbed 58.2% to $2.89bn, beating analysts’ exceptions of $2.83bn.
Sales growth for the unit in North America climbed 10% and 8% in the rest of the world.
Amazon has grown its market share in cloud computing compared with rivals such as Microsoft and Google.
It introduced a new Asia Pacific region for its cloud unit this quarter.
Amazon has also been looking to expand its presence in other areas. The company has now launched its online grocery store in the UK.
Earlier this month, it announced a partnership with US bank Wells Fargo to offer discounts on student loans for members of its Prime Student services.