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Highlights
- Capital gains tax (CGT) applies to gains made on the sale of shares held outside tax-advantaged wrappers such as ISAs and pensions.
- The annual exempt amount for capital gains tax in the UK is £3,000 for the 2025/26 tax year.
- UK CGT rates on shares are 18% for basic rate taxpayers and 24% for higher and additional rate taxpayers as of 2024/25.
- Shares held within ISAs, pensions, and certain employee share schemes are generally exempt from UK CGT on disposal.
- Accurate record-keeping is essential to calculate gains, identify allowable costs, and report disposals correctly to HMRC.
Selling shares can be a profitable event for UK investors, but it can also trigger tax obligations under HMRC rules. The principal tax applying to the disposal of shares held outside tax-advantaged wrappers is capital gains tax, often referred to as CGT. Understanding how this tax works, what allowances apply, and how to report disposals correctly is essential for any UK investor active in the equity markets.
Many UK investors hold shares across a mix of accounts, including general investment accounts, Stocks and Shares ISAs, Self-Invested Personal Pensions (SIPPs), employee share schemes, and other structures. The tax implications of selling shares depend on where the shares are held, when they were acquired, how the gains compare to the annual exempt amount, and how they interact with the individual's broader tax position financial stocks.
This guide explores capital gains tax on share disposals in the UK, including the calculation framework, applicable rates, allowable deductions, and the reporting process. The content is educational and structured to support understanding rather than provide individual tax guidance.
What Is Capital Gains Tax?
Capital gains tax is the tax payable when an asset is sold or disposed of at a profit. For shares, the gain is generally calculated as the difference between the sale proceeds and the original cost (including allowable expenses such as broker commissions and stamp duty paid on purchase). The resulting gain, after any reliefs and the annual exempt amount, is taxed at the prevailing CGT rate.
Capital gains tax is separate from income tax, although it interacts with an individual's overall tax band when determining the applicable rate. Capital gains are typically reported through the Self Assessment system or through the HMRC real-time capital gains tax service, depending on circumstances. UK residents are subject to UK CGT on worldwide assets, while non-residents face a more limited CGT scope on UK property and certain UK assets.
The Annual Exempt Amount
Every UK resident has an annual exempt amount for capital gains tax. This is the amount of gains an individual can make in a tax year without paying CGT. For the 2025/26 tax year, the annual exempt amount stands at £3,000, having been reduced from £12,300 in recent years. Gains within the annual exempt amount are not subject to CGT, and there is no requirement to report them unless overall disposal proceeds exceed a defined threshold.
The annual exempt amount cannot be carried forward. If it is not used in a tax year, it is lost. For investors with substantial gains, this can make planning the timing of disposals across tax years important. Spouses and civil partners each have their own annual exempt amount, which can be relevant when assets are jointly owned or transferred between partners.
UK Capital Gains Tax Rates
Capital gains tax on shares is linked to an individual’s overall income tax position. Following the Autumn Budget changes, gains on shares above the annual exempt amount are taxed at 18% for basic-rate taxpayers and 24% for higher- and additional-rate taxpayers. The taxable gain is added on top of income, meaning it can push part of the gain into the higher CGT band. For investors in financial stocks, this makes tax planning around disposals, allowances and timing more important.
Different rates may apply to gains on residential property and certain carried interest, but for share disposals, the 18% and 24% rates are the standard CGT rates. The tax is calculated on net gains after allowable losses and reliefs have been applied.
Calculating Gains on Share Disposals
Calculating the gain on a share disposal involves identifying the relevant acquisition cost, any allowable expenses, and the sale proceeds. For shares held outside an ISA or pension, the gain is the sale price minus the original cost. Allowable expenses can include broker commissions on both purchase and sale, stamp duty paid on the purchase, and certain other costs directly related to the transaction.
Where multiple parcels of the same share have been bought at different prices over time, the section 104 holding rule typically applies. This means the cost basis is calculated as a weighted average across all shares of the same class. Some special rules apply for shares acquired within 30 days of disposal (the bed-and-breakfasting rules) and for certain reorganisations and corporate actions.
Tax-Free Wrappers: ISAs and Pensions
Shares held within a Stocks and Shares ISA or a pension are generally exempt from UK capital gains tax on disposal. This means that selling shares within these wrappers does not trigger a CGT charge, regardless of the size of the gain. This makes ISAs and pensions valuable wrappers for long-term investors who anticipate building substantial gains over time.
The annual ISA allowance of £20,000 and pension contribution allowances limit how much can be sheltered each year. Many UK investors aim to use as much of their ISA and pension allowances as possible to build their tax-advantaged holdings over time. The bed-and-ISA strategy involves selling shares in a general investment account and repurchasing them inside an ISA, although the sale itself can still trigger CGT before the wrapper is established.
Capital Losses and Loss Relief
Not all share disposals result in gains. Capital losses arise when shares are sold for less than their acquisition cost. These losses can be set against capital gains in the same tax year, reducing the overall CGT liability. Unused losses can be carried forward indefinitely to offset future gains, provided they are reported to HMRC within the time limits set in the tax legislation.
Loss relief is an important tool for managing CGT exposure. UK investors who have unrealised losses on certain holdings may consider crystallising those losses to offset realised gains within the same tax year. However, the share matching rules (including the 30-day rule) need to be considered to ensure the loss is properly recognised.
Reporting Share Disposals to HMRC
Reporting requirements for capital gains depend on the size of the gain and total disposal proceeds. If gains exceed the annual exempt amount or total proceeds exceed four times the annual exempt amount, disposals generally need to be reported through Self Assessment. The deadline for filing a Self Assessment tax return for online submissions is 31 January following the end of the tax year.
Where disposals do not exceed the relevant thresholds, no reporting may be required. However, maintaining records of all disposals is good practice, even when reporting is not required. Records should be kept for at least the period required by HMRC, generally at least 22 months after the end of the relevant tax year for individuals filing Self Assessment.
Specific Situations: Inherited Shares and Gifts
When shares are inherited, they receive a step-up in cost basis to their market value at the date of death. This means that any pre-existing unrealised gains are typically not subject to CGT, although inheritance tax may apply to the estate. Subsequent disposals are taxed on the basis of the inherited cost.
Shares gifted to a spouse or civil partner are typically transferred at no gain, no loss for CGT purposes. Gifts to other individuals are treated as disposals at market value for CGT purposes, which can give rise to a chargeable gain even if no cash changes hands. Specific reliefs, such as holdover relief, may apply in certain circumstances.
Employee Share Schemes
Many UK employees receive shares through workplace schemes such as Share Incentive Plans (SIP), Save As You Earn (SAYE), and Enterprise Management Incentives (EMI). The tax treatment of shares received through these schemes can be more favourable than ordinary share disposals, with some schemes offering exemptions from CGT or relief on income tax depending on the structure and holding period.
Shares from approved employee schemes can sometimes be transferred directly into an ISA shortly after vesting, preserving the tax-free status of any subsequent gains. The specific rules vary by scheme type, so it is important for participants to understand the conditions of their particular plan and any time-sensitive opportunities to optimise tax outcomes.
International Shares and Foreign Currency
UK residents holding international shares are subject to UK CGT on disposals on the same basis as UK shares. Gains and losses on foreign-currency-denominated shares need to be calculated in pounds sterling, using the exchange rates at the dates of purchase and sale. This can result in CGT on a currency component of the gain even if the share's value in its original currency has not changed.
Some countries also impose their own taxes on share disposals by non-residents. Double taxation treaties between the UK and other countries can reduce or eliminate the impact of double taxation. UK residents should ensure they understand both UK and foreign tax implications when selling international shares.
Capital gains tax is a key consideration when UK investors sell shares held outside tax-advantaged wrappers. With the annual exempt amount reduced in recent years and CGT rates at 18% and 24% on share disposals, the role of ISAs and pensions in sheltering long-term equity gains has become increasingly important.
Understanding the calculation framework, available reliefs, and reporting obligations is central to managing tax outcomes effectively. Accurate record-keeping, awareness of timing considerations across tax years, and effective use of available wrappers can all contribute to a more efficient approach to share disposal taxation.
