Monaghan-born White emigrated to the US and made his fortune from catalogues and customer data. He floated his data-crunching group Abacus Direct on Nasdaq in 1997. Two years later he bagged €63m in stock when selling the company to internet ad broker DoubleClick for €1.05bn.
There have been some massively profitable Manhattan property flips. He sold a house at 118 East 70th Street to Woody Allen for €22.8m in 2006. He then doubled his money on another townhouse, selling it two years ago for €31.6m.