A stocks and shares ISA is a pure tax wrapper—no income tax, no capital gains tax, no Self Assessment line. The headline is simple. The detail starts to matter when you move money in and out, hold AIM shares, die, or move abroad.
What follows is a 2026/27 reference for the tax rules, including the changes that took effect from April 2024 (multiple ISAs of the same type, partial transfers) and the post-2025 reforms to the AIM IHT exemption.
Income tax inside an ISA
Inside the wrapper:
- UK dividends are paid free of UK income tax. They are not added to your dividend allowance and do not count toward your tapered personal allowance.
- Interest from bonds or cash held inside the ISA is paid free of UK income tax. It does not consume your personal savings allowance.
- Foreign dividends may have withholding tax deducted at source by the originating country. The ISA wrapper does not shield against foreign withholding—only UK tax.
The most common foreign withholding rates UK investors encounter:
| Country | Standard withholding rate | UK ISA recovers? |
|---|---|---|
| US | 30%, reduced to 15% with W-8BEN | No (15% sticks) |
| Germany | 26.375% | Reclaimable, but rarely worth the paperwork |
| Switzerland | 35% | Reclaimable, also rarely worth it |
| France | 28% | Reclaimable |
Most large funds and ETFs handle this automatically. The 15% US withholding on dividends inside an ISA is the most common drag UK investors do not realise they are paying.
Capital gains tax
Realised gains inside a stocks and shares ISA are exempt from UK capital gains tax. You do not have a CGT allowance to use up on ISA disposals—every gain is sheltered.
This is the rule that has become more valuable every year. The CGT annual exempt amount has been cut to £3,000 for 2026/27, down from £12,300 in 2022/23. CGT rates are 18% for basic-rate taxpayers and 24% for higher and additional rate, on most asset classes.
A taxable account that comfortably absorbed gains five years ago can now generate a tax bill on a relatively small disposal. The ISA wrapper is the most efficient way to make that problem disappear without doing anything clever.
Dividends—UK and overseas
UK dividends paid into your ISA are sheltered from the dividend allowance and dividend tax (currently 8.75%, 33.75%, 39.35% by band).
If you hold US-listed ETFs through your ISA—or US shares directly—the standard 30% US withholding tax is reduced to 15% if you have signed a W-8BEN form. Most platforms handle this automatically when you open a US share account.
A practical implication: a UK-domiciled ETF holding US shares (e.g. VWRP, ISF) is usually slightly more tax-efficient than a US-listed ETF, because the UK fund recovers part of the US withholding more efficiently than an individual investor can.
What you can hold inside a stocks and shares ISA
Eligible investments include:
- UCITS-eligible funds and ETFs.
- Investment trusts listed on a recognised stock exchange.
- Individual UK shares.
- US, European, and other internationally listed shares (most platforms support this).
- AIM-listed shares (with a 2026 caveat—see below).
- Corporate and government bonds.
Not eligible:
- Cryptocurrency.
- Unlisted shares (except AIM).
- Property directly (REITs are fine).
- Forex and most derivatives.
If you are transferring shares from a previous ISA, anything currently eligible can move freely.
The AIM ISA change
For years, AIM-listed shares held inside an ISA carried 100% business relief for inheritance tax, meaning a portfolio of qualifying AIM shares could pass to heirs without IHT after a two-year holding period.
From April 2026 that relief is reduced to 50%, meaning AIM ISA portfolios become subject to IHT at 20% (half the standard 40% rate) once total relief-qualifying assets exceed the £1m allowance.
Implications:
- Existing AIM ISA holdings still qualify, but the relief is capped going forward.
- The pure tax efficiency of AIM ISAs has diminished, and the case now leans more heavily on belief in the underlying companies.
- Holders should review their portfolios in the context of broader IHT planning.
This is not a niche change for most readers. But if you have been told an AIM ISA is “100% IHT-free”, the rule has moved.
ISAs and Self Assessment
You do not need to declare ISA income on a Self Assessment return. The wrapper is fully exempt from reporting.
The corollary: if HMRC ever asks where dividends or gains went on a return, they are asking about taxable account income, not your ISA.
Inheritance and the APS rule
When an ISA holder dies:
- The wrapper continues to receive its tax-free status until the earliest of: (a) administration of the estate completes, (b) all assets are withdrawn, or (c) three years and one day after the date of death. After that, normal tax applies.
- The ISA’s value sits inside the estate for IHT.
- A spouse or civil partner inherits an Additional Permitted Subscription (APS): a one-off ISA allowance equal to the higher of the ISA’s value at death or its value when the estate completes. This sits on top of the survivor’s own £20,000 annual allowance.
The APS is a meaningful planning lever for retired couples—it preserves the tax-free wrapper across both lifetimes, even though the wrapper itself is not IHT-exempt.
Moving abroad
You can keep an existing UK ISA after moving abroad, but:
- You can no longer pay into it.
- The wrapper’s tax shield only applies to UK tax. Your new country may tax the income and gains under their own rules.
- Some platforms restrict accounts for non-UK residents. Vanguard Investor, for example, asks customers to leave on becoming non-UK resident; AJ Bell and HL are more accommodating.
If you move to the US, an ISA’s investments are usually taxed there as a passive foreign investment company (PFIC), which is administratively painful in a way that almost always outruns the UK tax saving. UK readers planning a US move should usually liquidate the stocks and shares ISA before becoming US resident.
A summary you can use
The 2026/27 stocks and shares ISA tax rules in one paragraph:
You pay no UK income tax or capital gains tax on anything held inside a stocks and shares ISA. Foreign withholding tax may apply to overseas dividends, but the wrapper is otherwise watertight. ISAs are part of your estate for inheritance tax, but a spouse can inherit an Additional Permitted Subscription. AIM ISA inheritance relief has been reduced from 100% to 50% as of April 2026. None of it goes on Self Assessment.
For the practical “how to use it” overview, see the complete UK guide to stocks and shares ISAs.
Frequently asked questions
- Do I pay capital gains tax on a stocks and shares ISA?
No. All gains realised inside a stocks and shares ISA are exempt from UK capital gains tax. You don't need to record disposals on a Self Assessment return either—HMRC treats the wrapper as if it doesn't exist for personal-tax reporting.
- Do ISAs count toward inheritance tax?
ISAs form part of your estate for IHT. A spouse or civil partner can inherit an "Additional Permitted Subscription" equal to the value at death, on top of their own £20,000 allowance, but the wrapper itself isn't IHT-exempt.
- What happens to my ISA if I move abroad?
Once you become non-UK resident, you cannot pay into the ISA. Existing investments stay tax-free under UK rules but may be taxed by your new country of residence. Always check local rules before moving—particularly for the US, where the wrapper is administratively painful.
