The Ryan family and Ryanair chairman Mr David Bonderman stand to realise about £19.5 million each from the sale of stakes of 2.4 per cent in the airline as part of the London float, based on yesterday's Dublin closing price of 515p.

Meanwhile chief executive Mr Michael O'Leary should realise close to £9.8 million before expenses from the sale of his 1.2 per cent stake.

The precise amount that the shareholders will receive from selling their shares will not be known until the price is struck for the London float, although it is unlikely to differ much from the current trading range.

The three parties, who own more than 60 per cent of the company between them, have done well out of their investment in the airline, whose share price has surged from 195p when it floated on the Irish Stock Exchange last May to 515p yesterday.

Dr Tony Ryan and his sons Declan, Cathal and Shane, own their share of the company through a family trust. They raised £48 million from the sale of shares in last May's flotation but retain a 33 per cent stake in the airline worth £269 million, based on yesterday's close.

Meanwhile Mr O'Leary, who exchanged a profit-sharing bonus scheme under which he was entitled to 50 per cent of company profits for Ryanair shares, has a 14.1 per cent shareholding, now valued at £114.9 million.

Mr Bonderman, whose stake is held through investment vehicle Irish Air LP, paid £1 million and provided a loan of £24 million to acquire a 19.9 per cent stake in the airline in August 1996. Irish Air's stake has since fallen to 14.6 per cent stake and is worth around £119 million.