Forbes estimated O'Brien's wealth to be approximately $3.2 billion. Some time after his purchase of Quinta do Lago in 1998, but before Esat Telecom's sale to BT in 2000, O'Brien sold his home in Dublin and established a primary residence in Portugal. Media reports suggested that the move was spurred by a then-existing exemption to capital gains tax in the Irish-Portuguese tax treaty, which reportedly would have saved O'Brien about €63 million in taxes. However, in 2013, the High Court officially ruled that O’Brien’s home was Quinta de Lago, Almancil, Portugal, and not Ireland, in the 2000/2001 tax year. While considering the flotation of Digicel on the New York Stock Exchange, a March 2006 filing to the Companies Registration Office (CRO) listed O'Brien's residential address as Sliema, Malta. Further reading Creaton, Siobhán. A Mobile Fortune: The Life and Times of Denis O'Brien. (Aurum Press, pp320). References External links Profile of Denis O'Brien at Digicel 1958 births People from Cork (city) People from Ballsbridge 20th-century Irish people People educated at The High School, Dublin Alumni of University College Dublin Carroll School of Management alumni 21st-century Irish people Irish businesspeople Businesspeople from County Cork Irish billionaires Irish chief executives Irish expatriates in Malta Irish expatriates in Portugal Irish Independent people Irish mass media owners Irish mass media company founders People from Sliema Sunday Independent (Ireland) people People associated with the National College of Ireland Living people