Britons paid a record £135.7 billion into Adult ISAs during the 2024/25 tax year, according to the latest figures from HM Revenue & Customs.
That was £32.7 billion more than in the previous tax year. Most of the increase came from Cash ISAs, although the amount going into Stocks & Shares ISAs also rose.
The figures provide a useful picture of how people were using ISAs when savings rates were relatively high. But the £135.7 billion headline needs some context: it represents money newly subscribed during one tax year, rather than the total amount Britons have accumulated inside ISAs.
How much went into ISAs in 2024/25?
HMRC’s latest statistics show a substantial increase in both the amount being paid into Adult ISAs and the number of accounts receiving subscriptions during 2024/25.
Adult ISAs in 2024/25
£135.7 billion
Total amount subscribed to Adult ISAs during the tax year.
+£32.7 billion
Increase in subscriptions compared with 2023/24.
16.8 million
Adult ISA accounts that received subscriptions during the year.
£952 billion
Total market value of Adult ISA holdings at the end of 2024/25.
The number of Adult ISA accounts receiving subscriptions increased from around 15 million to 16.8 million. However, that rise in account activity alone does not explain the size of the increase in money being contributed. The type of ISA receiving the money changed too.
Where did the extra £32.7 billion go?
Cash ISAs accounted for most of the increase. HMRC recorded an additional £26.1 billion of Cash ISA subscriptions compared with 2023/24, while Stocks & Shares ISA subscriptions increased by £6.1 billion. Lifetime ISA subscriptions increased by a further £472 million.
Subscriptions increased by 37.5% compared with 2023/24.
Subscriptions increased by 19.7% compared with 2023/24.
Where ISA subscriptions increased
Cash ISAs
+£26.1 billion
Stocks & Shares ISAs
+£6.1 billion
Based on HMRC’s aggregate figures, Cash ISAs accounted for about four-fifths of the overall £32.7 billion increase in Adult ISA subscriptions. This is a Calfiny calculation rather than a percentage published by HMRC.
The figures therefore show that cash was the main contributor to the record year. They do not show that Stocks & Shares ISAs were becoming less popular: subscriptions to them increased as well.
Why did Cash ISA subscriptions rise so strongly?
HMRC links the increase to the interest-rate environment during the period. It notes that Bank Rate and interest swap rates were at their highest levels during the 2023/24 and 2024/25 tax years, helping to increase the returns available on cash savings.
Higher savings returns can also make the tax treatment of interest more noticeable. Interest earned within an ISA is sheltered from Income Tax, while interest on savings held outside an ISA can potentially become taxable depending on a person’s circumstances and the allowances available to them.
HMRC says increased savings returns are likely to have made ISAs more attractive as a way of reducing potential Income Tax liabilities on savings interest. This provides a plausible explanation for the sharp rise in Cash ISA subscriptions, but it should not be interpreted as evidence about every individual saver.
Someone wanting to understand how the cash version of the account works can find the rules and features separately in How Does a Cash ISA Work?. The record subscription figures do not change those underlying rules.
Does £135.7 billion mean Britons now have £135.7 billion in ISAs?
No. HMRC uses the word subscription to describe money newly paid into an ISA during a particular tax year. The £135.7 billion figure therefore measures new Adult ISA subscriptions during 2024/25.
The total amount already accumulated inside ISAs is much larger. At the end of the tax year, HMRC estimated the market value of Adult ISA holdings at £952 billion, an increase of 8.5% from a year earlier.
Cash ISAs accounted for 44.1% of that market value, up from 41% a year earlier. Stocks & Shares ISAs accounted for 55.8%, down from 58.9%.
Those percentages describe the value held in the different types of ISA, not simply the money paid in during the year. For Stocks & Shares ISAs in particular, market movements can affect the value of existing holdings without any new money being subscribed.
Readers unfamiliar with the distinction between the different ISA structures can start with What Is an ISA and How Does It Work?.
Were people choosing cash instead of investing?
The statistics do not support such a simple conclusion.
Cash ISA subscriptions increased much more in cash terms, but Stocks & Shares ISA subscriptions also rose by 19.7%, or £6.1 billion. HMRC also recorded an increase of around 802,000 in the number of Stocks & Shares ISA accounts receiving subscriptions compared with the previous year.
At the same time, the share of subscribed accounts that were Cash ISAs fell to 64%, down 2.2 percentage points from 2023/24. This illustrates why the record Cash ISA inflow should not automatically be interpreted as people collectively moving away from investing.
The statistics show where new subscriptions went across the ISA market. They do not track the reasoning behind an individual’s decision, nor do they tell us whether someone chose cash instead of investments because of interest rates, investment risk, the time period for which they expected to hold the money or another consideration.
Cash ISAs and Stocks & Shares ISAs also expose money to different risks and potential returns. Those differences are covered in the dedicated Cash ISA vs Stocks & Shares ISA guide rather than attempting to decide between them from one year’s subscription statistics.
Why does using an ISA matter when savings rates are higher?
An ISA is a tax-exempt account. Interest received within a Cash ISA is free from Income Tax, while income and eligible capital growth within a Stocks & Shares ISA are also sheltered from the relevant UK taxes.
Outside an ISA, some savings interest can be received without paying Income Tax because of allowances such as the Personal Savings Allowance. Whether tax is actually due depends on the saver and their circumstances.
When savings rates rise, however, the same amount of cash can generate more interest. That can make the tax treatment of savings more relevant for some people, which is the connection HMRC makes when discussing the strong increase in Cash ISA subscriptions during 2024/25.
The purpose here is not to reproduce all of the tax rules. Calfiny’s ISA Tax Benefits Explained guide covers what the ISA wrapper protects and how those benefits work.
What does the record mean for today’s ISA saver?
There is an important timing difference between the new statistics and the ISA rules a saver faces today. The £135.7 billion figure covers subscriptions made between April 2024 and April 2025, while the HMRC statistics were published in September 2026.
For the 2026/27 tax year, the overall Adult ISA subscription limit remains £20,000. The amount someone pays across their ISAs during the tax year counts towards that overall allowance, subject to the specific rules applying to different ISA types.
The current allowance and how contributions across different ISAs interact are explained in ISA Allowance Explained.
A further change is due from 6 April 2027. For people aged under 65, the annual Cash ISA subscription limit will reduce to £12,000 within the overall £20,000 ISA limit. People aged 65 or over will continue to have a £20,000 Cash ISA limit.
That forthcoming change does not alter what the 2024/25 statistics tell us. It does mean, however, that the record Cash ISA subscriptions occurred under a different contribution framework from the one that will apply to many savers from April 2027.
What can the £135.7 billion figure actually tell us?
The latest HMRC figures provide strong evidence that ISA activity increased substantially during 2024/25. A record £135.7 billion was subscribed, £32.7 billion more than a year earlier, with Cash ISAs accounting for most of the increase.
They also show that the increase was not confined to cash. Stocks & Shares ISA subscriptions rose too, and more Stocks & Shares ISA accounts received subscriptions than in the previous year.
What the figures cannot establish is why each saver made those choices. HMRC links the Cash ISA increase to the higher interest-rate environment and the potential tax benefits of sheltering savings interest, but the aggregate data cannot tell us how important those factors were to each individual.
Nor should £135.7 billion be confused with the total value of money held inside ISAs. That broader figure stood at £952 billion at the end of 2024/25.
Cash ISAs drove a record year for ISA subscriptions
The scale of the increase is clear. Adult ISA subscriptions rose by £32.7 billion in a single year to reach a record £135.7 billion, and around £26.1 billion of that increase came from Cash ISAs.
Higher savings returns provide important context for that change, particularly because interest earned inside an ISA is sheltered from Income Tax. But the same statistics also show rising subscriptions to Stocks & Shares ISAs, making the picture broader than a simple shift from investing towards cash.
The most useful way to read the record figure is therefore as evidence of much greater ISA activity during 2024/25, with Cash ISAs responsible for most of the additional money subscribed. The reasons behind individual decisions — and which type of ISA may fit a particular purpose — cannot be determined from the headline number alone.
Research transparency Sources, Limitations & Methodology See how this research was carried out, what data was used and what the findings cannot tell us.
Methodology
This article uses HMRC’s Annual Savings Statistics 2026 and accompanying commentary to examine Adult ISA subscriptions during the 2024/25 tax year. The figures for total subscriptions, Cash ISA subscriptions, Stocks & Shares ISA subscriptions, numbers of accounts and market values are taken from HMRC. Calfiny’s estimate that Cash ISAs accounted for about four-fifths of the overall increase is calculated from HMRC’s reported £26.1 billion increase in Cash ISA subscriptions and £32.7 billion increase in total Adult ISA subscriptions.
Limitations
HMRC’s aggregate statistics do not identify why individual savers chose particular types of ISA. They therefore cannot establish why a particular person chose cash or investments, or whether higher interest rates were the deciding factor. The 2024/25 subscription figures should not be assumed to describe saver behaviour in 2026. Subscription figures measure money newly paid into ISAs during a tax year and are different from the total market value of ISA holdings. The ISA rules described are the current position as at 23 September 2026.
