The four executive directors of Kingspan have raised more than £27 million after selling about 5 per cent of the building materials company on the open market. It is understood that the 8.5 million shares, sold on Tuesday at 310p each, were placed with a variety of institutional investors, including some new British institutions, by ABN-AMRO Stockbrokers.

The Kingspan chairman, Mr Eugene Murtagh, has sold 4.67 million shares worth £14.5 million but retains a 23.99 per cent stake in the company which is worth £155 million at the current price. His brother, Mr Brendan Murtagh, sold 2.5 million shares for £7.8 million, but retains a 11.3 per cent stake, worth in excess of £60 million.

Two other directors also sold shares. Mr Eoin McCarthy sold 1.25 million shares for £3.9 million to move his stake in the company to 1.5 per cent, worth nearly £8 million. Mr Dermot Mulvihill sold 100,000 for £310,000 but holds 1.08 million shares worth £3.3 million.

The sale will improve the liquidity of Kingspan shares, but the Murtagh brothers - who founded the company and brought it to the stock market in 1989 - will still hold more than 35 per cent of the equity.