- Almost £900 billion is held in ISAs as the UK closes in on a £1 trillion ISA market
- Over £100 billion is held in Cash ISAs by 3 million individuals who have £20,000 or more but no Stocks and Shares ISA…
- …including over a million who have £50,000 or more in Cash ISAs but don’t invest
- Across the UK over 20 million adults hold an ISA, with around 3.6 million holding both stocks and shares and cash accounts, 4.4 million using ISAs solely to invest and 13.4 million with a Cash ISA only
- Around 40% of Brits hold an ISA, with 1 in 4 young adults under 25 using ISAs to save and invest
- The number of people using the full £20,000 ISA allowance surged to almost 2.5 million in 2022/23, although most pay in far less with over 40% of those paying in contributing under £2,500
- Gender investing gap sees less than a third (29%) of women putting their ISA contributions into a Stocks and Shares accounts, compared to 41% of men
“ISAs are an astonishingly popular savings and investment product, with millions of people across the UK taking advantage of the tax perks of an ISA to set aside money for the future,” says AJ Bell senior pensions and savings expert, Charlene Young.
“There is now close to £900 billion held by Brits in Cash and Stocks and Shares ISAs, plus a further £12 billion in Junior ISAs, as the UK closes in on a £1 trillion ISA market. The lag in HMRC’s data means we could actually be there already.
“With over half a trillion pounds invested in Stocks and Shares ISAs, most ISA wealth is invested for the long term. While investments dipped during the Covid pandemic, bullish markets and continued contributions have seen Stocks and Shares ISA wealth surge, with the total value of investments more than doubling in a decade from £241 billion in April 2014 to £511 billion in April 2024.
“Although government has missed the opportunity to reform the ISA market to make investing easier and help remove barriers between saving and investing, the figures demonstrate that ISAs continue to be astonishingly popular with savers and investors looking to shelter their wealth from tax.
How much are ISAs worth?
“The total value of Cash and Stocks and Shares ISAs held by UK adults is up over 80% in a decade, from £470 billion in 2013/14 to £871 billion in 2023/24. Around £511 billion is invested in Stocks and Shares ISAs, and £360 billion in Cash ISAs.
“A further £12.5 billion is held in Junior ISAs for children, with £7.5 billion in investment accounts and £5 billion held in cash.
- How many people in your age group use ISAs?
“More than 21 million UK adults hold at least one ISA, according to HMRC’s latest figures, meaning around 40% of us use the tax-efficient accounts.
“Plenty of people start saving and investing in ISAs early, with roughly a quarter of UK adults under 25 having an ISA, rising to almost half (46%) of over 65s.
“Although it illustrates that ISAs are a popular way for young people to start building up their savings and investments, the figures illustrate how challenging it is to encourage people to invest. Analysing HMRC’s contributions data, combined with population estimates, suggests that only around 7% of UK adults paid into Stocks and Shares ISAs during the year to April 2023. That includes some people who paid into both a Stocks and Shares and Cash ISA during the year, although they account for just 1 in 100 adults in the UK, highlighting the siloed nature of the ISA system, which is rarely used to save and invest simultaneously.
- Are ISA holders putting too much in cash?
“A significant number of UK adults hold a large Cash ISA balance but don’t invest. Over a million hold more than £50,000 in Cash ISAs but don’t invest in the Stocks and Shares version, while a whopping 4.5 million adults hold over £10,000 in Cash ISAs but nothing in Stocks and Shares ISAs.
“At a conservative estimate, those 3 million savers with a Cash ISA balance over £20,000 and no investments are sitting on at least £101 billion in Cash ISAs*. Government should be focussing efforts on encouraging those people to invest if it wants to promote a healthier long-term investing culture, and help more people unlock the potential to grow their wealth.
“Those people with large cash balances are prime candidates to start investing. They already have a cash buffer in place and should be in a position to put away some of their savings for the long-term.
- How much do your peers have in their ISA?
“The average ISA account is worth just over £34,000, although this varies significantly by age.
“Among ISA holders aged 65 and over, the average account is worth more than £64,000, while under 25s have around £8,300.
- How many people contributed to their ISA and what did they pay in?
“You don’t have to pay into an ISA every year, but they’re set up to encourage regular contributions with the overall allowance renewing every April. AJ Bell’s analysis shows that over half (51%) of ISA holders made some form of contribution in 2022/23, the latest year for which HMRC publishes data, with almost 11 million people paying into an ISA account.
“That includes over 7 million paying into a Cash ISA, more than 3 million into Stocks and Shares and a further 740,000 who paid into both.
“The average contribution into a Stocks and Shares ISA was £7,594, while a typical Cash ISA contribution was £6,993.
“Around 2.5 million ISA holders used the full £20,000 annual ISA allowance, although most pay in far less, with over half (54%) of ISA subscribers adding less than £5,000 to their account.
- Gender investing gap
“There are more female ISA holders than men, with just under 11 million women having an ISA account compared to 10.3 million men.
“However, men are much more likely to be investing their ISA, whereas women favour Cash ISAs more heavily. The trend is particularly noticeable among younger people, with the difference peaking in the 25-34 age group.
- Junior ISA holders
“Close to £12.5 billion is held in Junior ISAs for children across the UK. Although the number of cash Junior ISAs subscribed to remains higher than stocks and shares, the gap is narrowing with almost 600,000 investment Junior ISAs receiving subscriptions in 2023/24.
“While the maximum amount that can be paid into Junior ISAs each year stands at £9,000, the average is much lower, at around £1,350. Investment Junior ISAs tend to receive larger subscriptions, averaging £1,960 compared to £872 for an average contribution to the cash version of the account.
“Total annual JISA contributions have risen to over £1.8 billion, increasing sharply since the maximum annual limit on contributions for one child was set at £9,000 in 2020.
Background
Figures based on AJ Bell analysis of HMRC data published September 2025. Total values and subscriptions run up until 2023/24. Age and gender breakdown runs up until 2022/23.
Proportion of adult population holding an ISA estimated based on HMRC figures for total number of ISA holders, as well as ONS data on population size.
*Source: AJ Bell/HMRC. End of tax year 2022/23. HMRC data shows number of cash ISA holders only grouped into ISA balances ranging from £10,000-£14,999 through to £50,000 or more. AJ Bell analysis assumes the lowest value within the range to produce a conservative estimate of total balance held by those individuals.
