Cash ISAs versus stocks and shares ISAs
Cash accounted for most of the recent growth in ISA saving. In 2023 to 2024, Cash ISA subscriptions grew by 67%, a £27.9 billion increase, while stocks and shares ISA subscriptions rose by 10.9%, a £3.1 billion increase (HMRC, September 2025, reference year 2023 to 2024). Lifetime ISA subscriptions rose by 25.3%, an increase of £474 million.
| ISA type | Change in subscriptions, 2023 to 2024 |
|---|
| Cash ISA | +67% (£27.9 billion increase) |
| Stocks and shares ISA | +10.9% (£3.1 billion increase) |
| Lifetime ISA | +25.3% (£474 million increase) |
Source: HMRC, Annual savings statistics, September 2025 (reference year 2023 to 2024). Figures as at July 2026, subject to change. The surge in cash saving is often linked to higher interest rates in that period, though HMRC does not attribute a cause.
ISA wealth by age
Average ISA balances rise steeply with age. At the end of the 2022 to 2023 tax year, the average ISA market value was around £8,288 for holders under 25 and £10,556 for those aged 25 to 34, compared with around £64,386 for holders aged 65 and over (HMRC, September 2025).
| Age group | Average ISA market value (end 2022 to 2023) |
|---|
| Under 25 | ~£8,288 |
| 25 to 34 | ~£10,556 |
| 65 and over | ~£64,386 |
Source: HMRC, Annual savings statistics, September 2025 (average market value by age, end of 2022 to 2023). Figures as at July 2026, subject to change.
What the numbers mean
The headline is scale and concentration: a large pool of ISA wealth, held disproportionately by older savers. Average balances of around £64,386 for the 65 and over group, against roughly £8,288 for under-25s, point to decades of accumulation (HMRC, September 2025, end 2022 to 2023). Source: gov.uk, as at July 2026, subject to change.
In our view, three things stand out for families thinking ahead. First, ISA saving is growing quickly, with Adult ISA holdings up 20.1% in a single year to around £872 billion (HMRC, September 2025). Source: gov.uk, as at July 2026, subject to change. Second, much of that recent growth sat in cash rather than investments. Third, and often overlooked, the tax advantages of an ISA generally stop at death. That combination means an ISA can be a meaningful part of the estate that a family later has to account for. These are general observations from the published data, not a comment on any individual's position, and outcomes depend on circumstances.
An ISA shelters income and gains during your lifetime. It does not, on its own, place the money outside your estate for inheritance tax.
ISAs and inheritance tax
ISAs are generally counted as part of your estate for inheritance tax, even though income and growth inside them are tax-free while you are alive. Where an estate is above the available thresholds, the standard inheritance tax rate is 40%, and the nil-rate band is £325,000 per person (gov.uk, Inheritance Tax, as at July 2026, subject to change). Transfers between spouses and civil partners are generally exempt, and a surviving spouse can usually inherit an extra ISA allowance.
Because ISA balances can be substantial, particularly for older savers, they can tip an estate over those thresholds. Our companion guides explain the wider picture: our estate planning guide sets out how the pieces fit together, Inheritance Tax Explained covers the thresholds and rates, and our page on inheritance tax on ISAs looks specifically at how ISAs are treated on death. Many people choose to discuss their own position with a qualified professional before acting.
Sources and methodology
Every statistic on this page comes from HMRC Accredited official statistics, cited inline at the point of use with its reference period. The main release is HMRC Annual savings statistics, published 18 September 2025, with prior-year figures from the September 2024 release. Figures are current as at July 2026 and are subject to change.
Note on interpretation: the number of accounts subscribed to in a year differs from the number of individual holders, and market-value figures reflect accumulated holdings rather than a single year of saving. Figures are rounded as published by HMRC and are not adjusted or extrapolated here.
Frequently asked questions
How much is held in ISAs in the UK?
The market value of Adult ISA holdings was around £872 billion at the end of the 2023 to 2024 tax year, a 20.1% rise on the previous year (HMRC, September 2025). This covers accounts built up over many years, not just money paid in during a single year. Figures are as at July 2026 and subject to change.
How many people have an ISA in the UK?
About 39.4% of adults in England had an ISA at the end of the 2022 to 2023 tax year, and around 15 million Adult ISA accounts were subscribed to in 2023 to 2024 (HMRC, September 2025). Accounts subscribed to can exceed the number of people, since one person may hold several. Figures as at July 2026, subject to change.
Are cash or stocks and shares ISAs more popular?
By recent growth, cash led clearly. In 2023 to 2024, Cash ISA subscriptions grew by 67% (a £27.9 billion increase), while stocks and shares ISA subscriptions rose 10.9% (a £3.1 billion increase), per HMRC, September 2025. The two serve different aims, and suitability depends on circumstances. Figures as at July 2026, subject to change.
Do ISAs count towards inheritance tax?
Generally yes. ISAs are usually part of your estate for inheritance tax, even though they are tax-free during your lifetime. Where an estate exceeds the available thresholds, the standard rate is 40% and the nil-rate band is £325,000 per person (gov.uk, as at July 2026, subject to change). This is general information; individual outcomes depend on circumstances.
Which age group holds the most in ISAs?
Older savers hold the largest balances on average. At the end of 2022 to 2023, the average ISA market value was around £64,386 for holders aged 65 and over, against roughly £8,288 for under-25s and £10,556 for those aged 25 to 34 (HMRC, September 2025). Figures as at July 2026, subject to change.
Do these ISA statistics cover the whole UK?
The HMRC ISA subscription and market-value figures cover the United Kingdom. Some breakdowns, such as the proportion of adults holding an ISA, are reported for England (HMRC, September 2025). Estate and inheritance tax rules described here apply to England and Wales, with Scotland and Northern Ireland differing in some respects. Figures as at July 2026, subject to change.
About Fairchild Oldfield
The Fairchild Oldfield team brings together estate planning, tax, independent financial advice and client care, working with families across England and Wales.
Fairchild Oldfield are estate planning specialists and will writers, not a firm of solicitors. This article is general information based on practical experience and published official statistics, not legal, tax or financial advice.
Important: This article is general information only and is not legal, tax or financial advice. Reading it does not create a professional relationship. Statistics are drawn from named HMRC official statistics and cited inline; the estate and tax rules described are based on the law of England and Wales, and other UK jurisdictions may differ. Figures and rules are current as at July 2026 and are subject to change. ISAs and other investment products are regulated, and information here is educational rather than a recommendation. Before acting, many people choose to seek advice from a suitably qualified professional, such as a solicitor, a STEP practitioner, an accountant, or an FCA-authorised financial adviser, who can consider your individual circumstances.
