Having started insulation group Kingspan in the back of a pub in Kingscourt, Co Cavan, founder and now chairman Eugene Murtagh's 17pc stake in the firm has rocketed in value in the past year to over 900m, building on the fact that the shares have risen more than tenfold since 2009. With other assets, Murtagh should comfortably be in the billionaires' club. The company recently reported sales of 3bn, with profits having jumped by 33pc to 341m, and is growing through acquisitions and building new factories across the world.
Shares are up more than 25pc this year. Helping to drive this is the company's expansion into other green construction technologies including LED lighting, fuel and energy storage, solar panels, hybrid energy systems and small wind turbines. Tesla-driving son, Gene, now runs the business. The Murtaghs also own the Hempel Hotel in London, another in Amsterdam.