ISA Changes from April 2027

7 minute read

What advisers and investors need to know

Key takeaways

From 6 April 2027, Investors under age 65 will be limited to £12,000 per annum into a Cash ISA.
The overall ISA allowance remains £20,000.
Anti-circumvention rules will be in place for anyone trying to hold cash in stocks and shares ISAs or transfers to a cash ISA.

Index

The ISA landscape is set for its most significant change in years from 6 April 2027. The Government has confirmed reforms designed to create a 'nation of investors' while maintaining the ISA’s position as the UK's flagship tax-efficient savings vehicle. The changes will primarily affect Cash ISAs but could alter how advisers approach cash management and investment choices within stocks and shares ISAs.

1. Why are ISA rules changing?

The Government's stated objective is to encourage more savers to invest in the long term rather than hold large amounts of cash. Policymakers believe that increasing participation in stocks and shares (including funds) could improve long-term consumer outcomes while also supporting investment in UK businesses and growth assets. The reforms seek to redirect some savings from cash towards investment-based solutions without reducing the overall tax advantages available through ISAs.

Importantly, the Government has chosen not to reduce the overall annual ISA allowance. Instead, it is introducing restrictions on how much of that allowance may be allocated to cash by certain investors.

2. The headline change: a new Cash ISA limit

From 6 April 2027, individuals aged under 65 will be subject to a new annual Cash ISA subscription limit of £12,000. Currently, investors can allocate the full £20,000 annual ISA allowance to cash. Under the new rules, this will no longer be possible for those under the age of 65.

The age test is applied at the end of the tax year. Therefore, an individual who turns 65 at any point during the tax year will benefit from the age 65 relaxation from the start of that tax year.

The overall ISA subscription limit will remain £20,000 per tax year. This means that investors under 65 can still contribute up to £20,000 across their ISA portfolio, but only £12,000 can be placed into a Cash ISA. Any remaining allowance would need to be used in another ISA wrapper, such as a Stocks and Shares ISA, Lifetime ISA or Innovative Finance ISA.

For investors aged 65 and over, the £12,000 Cash ISA subscription limit will not apply. From the start of the tax year in which they turn 65, they will be able to subscribe up to the full £20,000 annual ISA allowance to a Cash ISA and transfer funds from a Stocks and Shares ISA or Innovative Finance ISA into a Cash ISA.

However, this age-based relaxation applies only to Cash ISA subscriptions and transfers. It does not remove the separate rules affecting cash and money market funds held within investment ISAs. Investors aged 65 and over will still be subject to the charge on interest earned on cash held within a Stocks and Shares ISA or Innovative Finance ISA, and a 100% allocation to money market funds could still result in a non-qualifying investment position.

3. Transfer restrictions to prevent circumvention

Alongside the new cash limit, the Government has introduced measures designed to prevent investors bypassing the restriction by subscribing to a non-cash ISA to only transfer to cash at a later date.

Investors under age 65 will no longer be permitted to transfer funds from a Stocks and Shares ISA or Innovative Finance ISA into a Cash ISA.

Cash ISA to Stocks and Shares ISA transfers will continue to be permitted.

4. Increased scrutiny of Money Market Funds (MMFs) within stocks and shares ISAs

Perhaps the most significant aspect of the reforms is the introduction of a maximum limit on MMFs within Stocks and Shares ISAs.

HMRC will introduce rules to prevent investors from simply holding 100% of invested assets in MMFs (near-cash assets) within a Stocks and Shares ISA while still benefiting from the full £20,000 allowance.

ISA managers will be required to monitor investment holdings to ensure they meet the qualifying investment criteria. ISA managers will also be asked to provide HMRC with annual statistical information about money market fund usage. For MMFs, the qualifying criteria is that less than 100% of invested assets are held. Where this is breached, the investor will be asked to take action to reduce the MMF exposure within 30 days. HMRC have confirmed that either:

some of the MMF holding must be moved to a non-MMF asset
The MMF holding is removed from the ISA ‘wrapper’

Advisers should avoid recommending or allowing a portfolio to remain 100% invested in money market funds, even where this is intended only as a temporary position.

ISA managers may impose a default option should the investor take no action to ensure the investments remain qualifying. This may be to move a small proportion of the MMF holding to a non-MMF holding, for example. The ISA manager's terms and conditions will confirm where this applies.

5. Flat rate charge on cash held within investment ISAs

From 6^th April 2027, a new flat-rate charge on interest earned from cash balances held within Stocks and Shares ISAs and Innovative Finance ISAs. This again aims to discourage investors from using investment ISAs primarily as cash-holding vehicles.

The charge will be deducted within the ISA at a flat rate of 22%, regardless of the investor’s marginal rate of income tax. The Personal Savings Allowance, starting rate for savings and personal allowance will not reduce the charge. Equally, higher- and additional-rate taxpayers will not have to pay any further tax on the interest through self-assessment.

For example, where a £1,000 cash balance is held within a stocks and shares ISA, earning 2.23% this would, if paid annually be calculated as follows:

£1,000 * 2.23% = £22.30

Flat rate charge deducted = £4.90

Net interest allocated = £17.40

This has the impact of reducing the rate to 1.74%

6. Practical implications

For many clients, the immediate impact may be limited. Investors who already use Stocks and Shares ISAs and rarely hold significant cash balances may notice little change.

However, the reforms are likely to be particularly relevant for:

Clients with substantial cash savings, perhaps those who fully utilise their cash ISA limit each year
Investors approaching retirement who favour capital preservation over potential for higher returns
Clients undertaking phased investment strategies
Individuals building emergency funds within ISA wrappers
Higher-rate taxpayers seeking tax-efficient homes for significant cash deposits.

7. What advisers should check at the next client review

From 6 April 2027, client reviews should consider not only the new Cash ISA subscription limit, but also how cash and money market funds are being used within stocks and shares ISAs. Advisers should establish whether cash is being held for a clear planning purpose, such as short-term liquidity or phased investment, or whether the ISA has drifted into being used as a cash substitute.

the client’s age during the tax year and the resulting Cash ISA subscription and transfer options;
whether planned subscriptions make appropriate use of the overall £20,000 ISA allowance;
the purpose and likely duration of any cash balance held within a Stocks and Shares ISA or Innovative Finance ISA;
whether money market fund holdings could create a non-qualifying investment position, particularly where they represent 100% of invested assets; and
whether an alternative home for short-term cash would better meet the client’s objectives, liquidity needs and attitude to investment risk.

8. Conclusion

The April 2027 ISA reforms represent a deliberate policy shift towards encouraging investment over cash savings. While the overall £20,000 ISA allowance remains intact, the new £12,000 Cash ISA limit for under-65s, combined with transfer restrictions and proposed anti-avoidance measures, will require advisers and investors to rethink how ISA allowances are used.

What is critical is that the benefit of ISAs is not lost when clients read about these changes. Although these changes add complexity, they should not discourage clients from making appropriate use of their ISA allowances.

Approver: Quilter October 2026

Q 01404/206/19059

The information provided in this article is not intended to offer advice.

It is based on Quilter's interpretation of the relevant law and is correct at the date shown. While we believe this interpretation to be correct, we cannot guarantee it. Quilter cannot accept any responsibility for any action taken or refrained from being taken as a result of the information contained in this article.

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