Rules and government policy checked on 27 September 2026.
A change to a savings allowance can make an ordinary money decision feel urgent. Should you move something? Open another account? Start investing money you had intended to keep in cash?
The government says it wants more people to invest, arguing that this can improve long-term returns for savers and provide more investment for UK businesses. Its answer is to reduce how much most under-65s can put into a Cash ISA from April 2027, while leaving the overall ISA allowance at £20,000. The intended nudge is to make investing more attractive than holding large sums in tax-free cash. The Budget speech and HMRC's policy paper set out that rationale.
I think that is the wrong way round. Making cash saving less attractive does not make investing suitable for money people may need soon. My concern is that some people will invest more, while others may simply spend more or save less. If that happens at scale, it could leave more people less prepared for retirement and add to pressure on the state later. The sensible response is still to match the money to its purpose, not to take investment risk to preserve a tax break.
What applies now, and what changes next?
For the current 2026/27 tax year, the overall adult ISA allowance is £20,000. You can put that into cash ISAs, subject to your eligibility and any allowance already used elsewhere. The tax year ends on 5 April 2027. Current GOV.UK ISA guidance.
The new limit takes effect on 6 April 2027:
| ISA allowance | 2026/27 | From 6 April 2027 |
|---|---|---|
| Overall adult allowance | £20,000 | £20,000 |
| Cash ISA limit | Up to £20,000 | £12,000* |
The £12,000 limit is part of the £20,000 total, not an additional allowance. The change is set out in the Individual Savings Account (Amendment) (No. 2) Regulations 2026, made on 10 September and coming into force on 6 April 2027.
The £12,000 limit applies if you are 64 or under at the end of the tax year. From the start of the tax year in which you turn 65, the higher £20,000 cash allowance applies. HMRC's reform factsheet explains the age rule.
The new limit is not in force yet, but the regulations have been made. The current 2026/27 rules remain in place until 5 April 2027; the new limits and related restrictions start the following day. The final regulations contain the detailed rules.
What about money already in a cash ISA?
The £12,000 restriction is an annual contribution limit, rather than a ceiling on your accumulated cash ISA balance. Having £40,000 built up in cash ISAs would not mean having to remove £28,000. The regulations limit new subscriptions, not the balance already held. Regulation 6 of the final regulations amends the annual subscription limits.
Moving an existing ISA is a separate process from paying in new money. Use the receiving provider's ISA transfer service, and check charges and account restrictions before proceeding. Withdrawing into your bank account and then paying into another ISA can lose the protection of a proper transfer. GOV.UK transfer guidance.
There are changes beyond the allowance
Three accompanying changes deserve attention if you use investment ISAs:
- Transfers into cash ISAs: money in stocks and shares and innovative finance ISAs cannot be transferred into a cash ISA while you are below the higher age threshold. The restriction covers current-year and previous-year contributions. Transfers between cash ISAs remain possible.
- Interest on uninvested cash: interest paid on cash held in stocks and shares and innovative finance ISAs is subject to a charge at the savings basic rate, set to be 22% from April 2027. It applies to the interest, not 22% of your balance, and also affects people aged 65 and over. The ISA manager pays the charge.
- Money market funds: these can be held in a stocks and shares ISA, but they cannot make up all the investments other than cash. Adding an uninvested cash balance does not get around that restriction.
These details come from the final regulations, HMRC's reform factsheet and the technical note on savings tax rates. This discussion concerns ordinary adult ISAs; Lifetime and Junior ISAs have separate rules.
If you were planning to move investment ISA money into cash as a spending date approaches, give that plan some attention before April. Ask your provider how the final rules will affect it. Avoid an irreversible move based on a headline.
Keep the purpose of the money in view
Suppose you expect to save £15,000 towards a house move during 2027/28 and fall within the lower age limit. Under the new rules, £12,000 could go into a cash ISA, assuming sufficient unused allowance. The remaining £3,000 would need another suitable home.
A savings account outside an ISA is one option. Whether its interest is taxable depends on your income, interest earned and available allowances. Compare what you would actually keep after tax, alongside access terms. GOV.UK savings tax guidance.
Investing that £3,000 introduces a different question: could you cope with it being worth less when the moving bill arrives?
The FCA recommends keeping an accessible emergency fund and approaching investing over at least five years. Even then, losses remain possible. A tax advantage cannot make an unsuitable timescale suitable. FCA investing guidance.
A sensible response
Write down how much new cash you expect to save next tax year, when you will need it, and whether your plans involve moving money between ISA types. Cash has a job: emergency reserves and near-term spending need security and access. Investments have a different job: pursuing long-term growth, with the risk of losses along the way.
If you are likely to exceed the £12,000 cash limit, compare suitable alternatives. If you hold uninvested cash or money market funds in an investment ISA, read your provider's reform updates too.
Then revisit the position as providers explain how they will apply the final rules. A tax allowance is useful, but it should not dictate whether you save, spend or take investment risk. The useful outcome is being financially prepared, with money available when you need it and investments reserved for goals that can tolerate uncertainty.