Media-shy Meath businessman Pat McDonagh (68) made a fortune from software in the 1990s, but in recent years is believed to account for his financial success thanks to canny and well-timed property investments.
He initially made his money from CBT Systems, Skillsoft and e-learning firm Riverdeep. At one stage during the dotcom boom, his Riverdeep stake was worth about €800m and he later cashed in over a quarter of it.
More recently, he backed Arklow developer Greg Kavanagh, who bought land in and around Dublin around the bottom of the market and sold or developed it in order to book huge profits. His assets have included land in north Dublin and the capital's wider commuter belt, as well as a number of stud farms with large land holdings, where he previously bred horses.
Last year, he put the family home, Corbalton Hall, a 300-acre estate on the market. There was a variety of other investments, including a radio station, nursing home business, sausage-making business and a video software firm.