Yes. Stock investment gains are subject to Capital Gains Tax (CGT). This is a tax that you can be required to pay when you sell or dispose of an asset for a profit. Everyone in the UK has an annual Capital Gains Tax allowance. For the 2021-22 tax year, this is £12,300. This means that any gains realised under this amount incur no Capital Gains Tax. CGT is due on gains above this amount, however. One way to minimise CGT liabilities is to buy shares within a Stocks & Shares ISA. In this kind of investment account, all capital gains are tax-free.