Capital Gains Tax (CGT) is normally charged at a simple flat rate of 20% when you sell shares unless they are in a CGT free investment such as an ISA or qualifying pension.
If you only pay basic rate tax and make a small capital gain, you may only be subject to a reduced CGT rate of 10%. Once the total of your taxable income and gains exceeds the higher rate threshold, the excess will be subject to 20% CGT. There is also an annual CGT exemption. This means that in the current tax year you can make £12,300 of gains before paying any tax. The allowance applies to each member of a married couple or civil partnership.
The usual due date for paying any CGT you owe to HMRC when you sell shares is the 31 January following the end of the tax year in which a capital gain was made. This means that CGT for any gains crystalised before 6 April 2023 will be due for payment on or before 31 January 2024.
It is also important to note that the annual exempt amount applicable to CGT is to be more than halved from April 2023. The exempt amount will be reduced from £12,300 to £6,000 from April 2023, before a further reduction to £3,000 from April 2024. This means that taxpayers with small gains should consider the benefits of crystalising these gains before 6 April 2023 in order to fully utilise the £12,300 allowance for 2022-23.
The normal way to report a gain on the sale of shares is to complete the relevant sections of your Self-Assessment tax return in the tax year after the gain was made. When calculating your gain, you can deduct certain costs of buying or selling shares such as stockbrokers’ fees or Stamp Duty Reserve Tax when you bought the shares.