Brothers John (24) and Patrick (27) have created the fastest billion-euro fortune in Irish history. The Tipperary technology boy wonders were always marked out for big things, selling their first company Auctomatic for $5m when still teenagers in 2008. After dropping out of Harvard and MIT, the brothers teamed up to found Stripe in 2010.
It is a brilliantly simple way of making paying online incredibly easy. With initial backing from Tesla founder Elon Musk and Paypal's Peter Thiel, the company kept on growing. Since then it has raised close to €250m from investors including Visa, with its most recent funding round last July, valuing the company at $5bn.
"There is really an issue in Silicon Valley with companies getting a bit ahead of themselves in terms of their own self-perception of their own success," cautioned Patrick last January. Forbes recently described it as "a mobile payments phenomenon".
It has been estimated that 27pc of Americans have bought something using Stripe over the last year, and revenues are pegged somewhere north of $450m. We conservatively assume the brothers have managed to hold on to about 35pc.
The brothers have also got into the Silicon Valley hobby of flying planes, with John logging a fair few hours in Cessnas, Diamond DA-40s and Tomahawks.