By way of concession to taxpayers whose income tax liability may be higher than the value of the shares, such taxpayers will have the choice of making a payment on account capped at the value of the shares. The balance of income tax will become due for payment where the taxpayer makes a gain on the disposal of these or other shares. This provision applies where the options were exercised before or on 6 February 2003. If a taxpayer wishes to avail of this provision, he or she must notify the Revenue Commissioners by 1 June this year.