LOS ANGELES-Amazon, formed 25 years ago, has eclipsed Microsoft to become the world's most valuable listed company.

The online giant was worth $797bn (£634bn) when the US stock market closed on Monday after rising 3.4% and moved past Microsoft, valued at $789bn.

Jeff Bezos, the founder of Amazon, is the world's wealthiest man, with riches of $135bn, according to Bloomberg's billionaire index.

He overtook Microsoft founder Bill Gates last year.

It is the first time Amazon has held the top position. The share prices of US tech giants have been on a rollercoaster in recent months on worries about sales and trade tensions.

First book

Founded by Mr Bezos in 1994, Amazon started life as a niche second-hand book seller and has become an online retailer of items ranging from fresh food to clothes.

The firm was created in a garage in a suburb of Seattle, Washington.

It was originally called "Cadabra," (as in "abracadabra") and in 1995 sold its first book - Fluid Concepts and Creative Analogies: Computer Models of the Fundamental Mechanisms of Thought, by Douglas Hofstadter.

In addition, it has won the rights to broadcast live sporting action, such as football from England's Premier League and ATP tennis.

The firm has developed a raft of other products and services, including the Kindle e-reader and Alexa virtual assistant, among others.

Major technology stocks have been volatile in recent months. In August, Apple became the world's first public company to be worth $1tn (£767bn), while Amazon achieved that valuation in September.

Since then, Apple's fortunes on the stock market have waned after it warned about a slowdown in China. The tech giant is now valued at $702bn.