The Sunday Times Irish Rich List 2013 will be published this weekend, with some young entrants making the list this year.
Limerick brothers Patrick and John Collison, aged 24 and 22, join the list after a value of €59m was placed on their holding in their latest company 'Stripe.'
Colm Murphy, who compiled the list for the Sunday Times, said that their business rocketed to success straight away.
"It's due to the rocketing success of the company in Silicone Valley called Stripe," he said.
"Stripe is a company that makes online payments easier, the two brothers made their first fortune when they were still teenagers and that was £3m they got for a company that they developed to sell management systems for eBay."