If you sell shares at a profit, the Capital Gains Tax (CGT) annual exemption may reduce the amount of your chargeable gains for that tax year. It generally applies to an individual’s net gains after allowable losses, but the exemption cannot usually be carried forward if you do not use it. The exemption amount, CGT rate and rules can change, so check the current guidance on revenue.ie and keep records of purchase costs, sale proceeds and dates. Tax treatment may also differ for shares held through a pension or other investment structure.