Amazon founder Jeff Bezos briefly overtook Bill Gates on Thursday to become the world’s richest person, as his worth hit $91.4bn (£70bn).
A sharp rise in Amazon shares meant Mr Bezos’s wealth eclipsed that of the Microsoft co-founder for a time.
But as Amazon shares fell back, Mr Gates regained the top spot according to Forbes.
Mr Bezos, 53, owns about 17% of the shares in Amazon, but also has interests in several other businesses.
Amazon shares have performed strongly over the past year and later on Thursday the company is expected to report a further increase in sales, one of the reason for the share price rise.
But in recent years Mr Bezos has focused much of his attention on his Blue Origin space rocket business and the Washington Post newspaper, which he bought in 2013, as well as some less publicised endeavours.
Here are five things you may not know about Mr Bezos:
1. His spending is rocketing
Earlier this year Mr Bezos paid $23m for an old textile museum in Washington DC. Once it’s converted to a family home, the Bezos family will be near neighbours in the exclusive neighbourhood with the Obamas, as well as Ivanka Trump and her husband Jared Kushner.
At least that’s what the Washington Post reported, a reliable source presumably since Mr Bezos bought the paper in 2013 with $250m of his own money.
The Bezos family also has homes in Seattle and Beverly Hills, but expenditure on property pales into insignificance compared to Mr Bezos’s foremost passion: rocket science.
Mr Bezos says he is selling about $1bn of Amazon stock every year to fund Blue Origin, the project he has founded to develop commercial space travel.
2. He is generous with bananas
It was Mr Bezos’s idea to start giving away bananas to passers-by in Amazon’s home town of Seattle – a generous gesture, especially since about 4,500 people reportedly take up the offer every day. But when it comes to philanthropy that is still peanuts compared to his peers.
While he and his family have given millions to good causes, Mr Bezos has been criticised for not doing enough. He doesn’t splash out for non-profits on the scale that Bill Gates, Facebook founder Mark Zuckerberg and others do, and is yet to join the 169 of his wealthy peers who have pledged to give away half their personal fortune.
But last month Mr Bezos appeared to be toying with new ideas in the philanthropic sphere.
He tweeted a request for suggestions as to how he could give money away that would have an impact “here and now” – a kind of next-day-delivery philanthropy.
It remains to be seen which proposals – ranging from libraries to tech talent in Africa – have caught his imagination.
3. His brother is the real hero
Good causes are already very much the domain of Jeff’s brother Mark Bezos. He switched from a career in advertising to work for the New York based anti-poverty organisation Robin Hood.
In a 2011 TED talk Mark Bezos relates how, attending his first fire as a volunteer, he was keen to show what he was made of. But someone else was asked to brave the smouldering building to rescue the owner’s puppy.
Mark was given the less glamorous task of finding her a pair of shoes. But she was still extremely grateful.
He draws this lesson: if you have something to give, however small, do it now.
Any ideas for Jeff?