Denis O'Brien (born 19 April 1958) is an Irish billionaire businessman, and the founder and owner of Communicorp. He was listed among the World's Top 200 in 2015 and is also Ireland's richest native-born citizen. His business interests also extend to aircraft leasing (Aergo Capital), utilities support (Actavo), petroleum (Topaz Energy, until 2016), and football (soccer), being a minority shareholder of Celtic F.C.. O'Brien was implicated by the Moriarty Tribunal as having improperly influenced the decision to award a mobile phone license to the Esat Digifone consortium, which he chaired.