Rosaleen (71), her sons Eamonn and Ronan, and daughters Clodagh and Rachel, are the majority owners of Mercury Engineering, one of the country's largest private electrical engineering companies. The business employs around 1,500 people and recorded a turnover of €600m in 2017. Mercury is involved in projects in data centres, life sciences, healthcare and fire protection. It also played a part in the construction of the Aviva Stadium. The Dublin-headquartered business was set up by the late Frank O'Kane in 1972 with his business partner Joe Morgan. O'Kane died suddenly in 2007, leaving an estate worth €108m to his wife and children.