Surge in Facebook's stock value has taken the internet entrepreneur past Ikea owner Ingvar Kamprad.
World Population Day will be observed around the globe on 11 July.
Nadella, appointed CEO in February 2014, has been determined to shrink Microsoft's unprofitable divisions.
Ortega's single-day gain was $500m more than the combined increase recorded by the world's 10 richest people.
Spanish billionaire has net worth of $69.8bn as of 5 June, slightly higher than Buffett's $69.2bn fortune.
The Varkey Foundation has urged UK teachers to apply for the 'Nobel Prize' of teaching.
Comedian Henry hints his daughter will not receive any of his reported £5m fortune.
Ultra-tough condom replaces latex with hydrogel that scientists claim enhances sexual pleasure.
Actor Ben Affleck brought his star power to a Senate hearing on Capitol Hill.
There are now a record 1,826 billionaires in the world says Forbes magazine
According to the Hurun Global Rich List for 2015, UK was on fifth place with a total of 80 billionaires.
Gates was taking part in an 'Ask Me Anything' session when he said he 'feels pretty stupid' for not learning another language.
Microsoft co-founder Bill Gates expresses concerns about bitcoin volatility as prices plummet.
Bitcoin, litecoin and dogecoin stabilise, rounding off positive week for cryptocurrency markets.
US businessman Donald Trump is considered one of the richest men in the world under the report.
Self-powered machine that turns faeces into fresh water developed through Gates Foundation.
The magazine includes a step-by-step bomb making guide, and advice on how to evade airport security.
Price of bitcoin jumps following Microsoft's acceptance of the cryptocurrency
Microsoft's acceptance of bitcoin for Windows, Windows Phone, and Xbox causes cryptocurrency price surge
Robots will probably develop the capacity to replace or destroy humans - how will we handle that?
Bitcoin's price bombs but fresh support comes from Microsoft founder Bill Gates
Bitcoin finds another prominent advocate in Microsoft founder Bill Gates.