John Magnier and JP McManus are set to earn a profit of €125 million from the sale of their holding in Manchester United plc to US billionaire Malcolm Glazer.
The pair agreed on Wednesday to sell the 28.89 per cent stake they have in the company, which represents one of the world's best known brands, for £3 (€4.40) a share. This values their 75.7 million shares at close to €335 million.
Brokers say that the stake, which they built up between 2001 and 2004, could have cost them €210 million.
This leaves their Virgin Islands-registered vehicle, Cubic Expression, with a surplus of €125 million.
Mr Glazer's offer, made through his vehicle Red Football Ltd, was unconditional.
Last autumn he also offered £3 a share through another company, the Glazer Family Partnership. However, it was reported at the time that the Irish duo turned this down as it was dependent on a number of pre-conditions.
Their acceptance now gave him control of close to 60 per cent of the company that owns the world's richest soccer club. By close of business last night he held control of 70 per cent of the shares.
Scottish mining millionaire Harry Dobson and a number of institutions also pledged to sell to the American, and it is believed he will have 75 per cent of the company by tomorrow.
One of the first casualties of a Glazer takeover could be the club's now legendary manager Sir Alex Ferguson. Reports last night said he was "repulsed" by the news, and would consult family and friends about resigning if Mr Glazer succeeds in buying the club outright.
The only thing now stopping Mr Glazer from doing that is the estimated 16 per cent of shares held by fans, who are vehemently opposed to him taking over the club.
They are opposed to the deal because his takeover will leave the club with debts estimated at over €400 million. It will have to pay this off from its revenues, which hit €250 million in 2004. This will limit its scope to buy new talent to ensure the club's position close to the top in English football.
Last night, Seán Bones, vice-chairman of Shareholders' United, a group of share-owning fans, said it would concentrate on trying to galvanise other supporters to oppose the Glazer bid. If this does not work the group is likely to organise a boycott of merchandising to hit the club's revenues.
"This is a unique situation; the plc has agreed to a sale that 93 per cent of its customers are against," he told The Irish Times.
He added that the Irish pair's agreement to sell their shares was viewed "very dimly" by the fans, who had seen them as their last defence against Mr Glazer.