Denis O’Brien, the telecoms and media entrepeneur, added $800 million (€579m) to his fortune in 2013, according to the just published Forbes Billionaires list, published by the eponymous US magazine.
Mr O’Brien, who is one of five Irish on the list, nonetheless slipped down one place to 234 in the rankings with a total fortune of $6 billion.
Irish citizen Pallonji Mistry, patriarch of Indian construction giant Shapoorji Pallonji Group, is the highest ranking Irish person on the list. He moved up 21 places to 82, after he got a $2.3 billion boost to his wealth this year thanks to the rising value of his 18.4 per cent stake in Tata Sons, the holding outfit of the $100 billion Tata conglomerate run by his younger son Cyrus.
With a fortune of $2.5 billion, Campbell's soup heir John Dorrance III is the third richest person in Ireland, but he has seen his position slide, down to 687 from 613 last year.
The fourth richest Irish person is Glen Dimplex founder Martin Naughton, who increased his wealth to $2.2 billion last year. He too however has slipped down the rankings, falling sixty places from 736 to 796.
The final Irish person making the list is investment supremo Dermot Desmond, who grew his wealth by $200 million last year, up to $2 billion. However despite increasing his fortune, Mr Desmond fell back to 869th on the list, down from 831 last year.
In the widerlist, Bill Gates is back on top after four-year hiatus with a $76 billion fortune, followed by telecom mogul Carlos Slim ($72bn) and Zara's Amancio Ortega ($64 bn). Facebook's Mark Zuckerberg was the year's biggest gainer, as his fortune jumped by $15.2 billion, to $28.5 billion.
This year the list welcomed 268 new faces, including WhatsApp founder Jan Koum ($6.8bn); Twitter cofounder Evan Williams ($3.5bn); Nigeria's first female billionaire Folorunsho Alakija; and Facebook's Sheryl Sandberg ($1.05bn).
Roughly two-thirds of the billionaires on the list built their own fortunes, 13 per cent inherited them and 21 per cent have been adding on to fortunes they received.
Of the 1,645 members on the list, 31 are under the age of 40. Little-known Perenna Kei, a newcomer to the list, displaces former Facebook cofounder Dustin Moskovitz as the very youngest billionaire. Hailing from Hong Kong, Kei oversees an 85 per cent stake in Logan Property Holdings through various companies and a family trust.
