Amazon has delivered a big prize to its CEO Jeff Bezos, who is now the richest person on Earth.

According to Bloomberg’s daily billionaire index, Bezos’ net worth reached US$105.1 billion Monday. Forbes also put Bezos at the head of the uber-rich class, but cited his net worth at $104.4 billion.

The majority of Bezos’ fortune comes from the 78.9 million Amazon shares he owns. That is about 17 per cent of the online book-selling company that he founded in a Seattle garage in 1994. Now the world’s biggest online retailer, Amazon had revenues of $136 billion in 2016.

When Amazon stock climbed 1.4 per cent Monday, it added approximately $1.4 billion to Bezos’ net worth. The company’s shares are up 7 per cent in 2018, after soaring 56 per cent in 2017. That allowed Bezos, 53, who also owns the Washington Post and private space tourism company Blue Origin, to cross the $100-billion net worth mark in November.

He and Bill Gates traded the title of world’s richest person several times last year.

The Microsoft founder is now worth $91.9 billion according to Forbes, and $93.3 billion according to Bloomberg, enough for No. 2 on both lists. But Forbes reports that Gates’ net worth crossed above $100 billion briefly back in April 1999. Adjusted for inflation, that would be $148 billion today. But he has given much of that away.

According to a Bloomberg analysis, Gates’ publicly disclosed donations show he has donated 700 million shares of Microsoft, worth $61.8 billion at today's value, along with $2.9 billion in cash. That would put his net worth at more than $150 billion.

In case you were wondering, Bezos’ fortune amounts to 1.78 million times the median U.S. household income.