Do I have to tell HMRC if I sell shares?

Do You Need to Tell HMRC When You Sell Shares?

Yes, you may need to tell HMRC if you sell shares — but it depends on how much profit you’ve made. When you sell shares for more than you paid, that difference is called a capital gain. If this gain exceeds the annual tax-free allowance (known as the annual exempt amount), you’re required to report it.

For the 2023–24 tax year, the annual exempt amount is £6,000. This means if your total capital gains across all assets — not just shares — are below this threshold, you typically don’t need to do anything. However, if your gains go over £6,000, you must report them to HMRC.

The most common way to report capital gains is by filling out a Self-Assessment tax return. Even if you’re not used to submitting one, you’ll need to register for Self-Assessment if you have a taxable gain above the allowance. The deadline for filing online is 31 January following the end of the tax year — so for the 2023–24 tax year, that’s 31 January 2025.

It’s important to keep accurate records of your share purchases and sales, including dates and prices. HMRC may ask for this information, especially if you’re questioned about your tax return. Some online share platforms now provide a ‘tax statement’ that helps make this easier.

Also worth noting: each individual has their own annual exemption, so married couples or civil partners can make the most of both allowances by holding shares in joint names or transferring them between each other — transfers between spouses are tax-free.

While the rules can seem complex, staying informed and keeping good records can save you time and stress. If you're unsure, speaking to a tax adviser or accountant can help clarify your obligations.