If the share grant is considered a BIK then you would indeed be liable for income tax, PRSI (4%) and health levy (2%) on the full value when you receive them (i.e. you will have a tax liability even if you don't dispose of them) and I think that the employer should be deducting these through payroll. If they are free shares through some sort of share option scheme then PRSI/health levy may not apply but just income tax on a self declared basis (see [broken link removed]). If you hold the shares and eventually sell them for a gain then CGT applies to the gain. I am not a tax expert so you should really get independent, professional advice.