Mountjoy (69) sold his Euristix software company to Fore Systems for €70m in shares back in 1999.
Two months later those shares had more than doubled to €154m, when Fore Systems was taken over by Marconi. The Sandycove man appears to have owned about 50pc of the company. Stakes in a number of start-ups also came good in spectacular fashion. Mountjoy had small chunks of Havok which was bought by Intel for €110m and Perlico, which was bought by Vodafone. There have also been investments in Zarion, Similarity Systems and Corvil. We’ve upped his wealth estimates considerably.