The 2027 ISA Overhaul: Will the New Cash Charge Harm Savers?

For decades, the ISA has offered a reassuringly simple promise: eligible interest, dividends and capital gains remain sheltered from personal tax while they stay inside the wrapper. From 6 April 2027, that promise becomes more complicated for cash held inside a non-cash ISA.

The government says its new anti-circumvention rules are designed to preserve the integrity of a lower Cash ISA limit and encourage more retail investment. The objective is clear. Whether the method will help cautious savers become confident investors is less certain.

The new rules in plain English

For people under 65, the annual Cash ISA subscription limit will fall to £12,000, while the overall ISA limit stays at £20,000. People aged 65 and over will retain a £20,000 Cash ISA limit. The government says the higher limit will apply from the start of the tax year in which a saver turns 65.

A flat 22 per cent charge will also apply to interest or alternative-finance returns paid on cash held inside a Stocks and Shares ISA, Innovative Finance ISA or other non-cash ISA. The ISA manager will pay the charge to HMRC, so the saver will not need to declare the interest. The Personal Savings Allowance will not offset it.

Transfers from non-cash ISAs into Cash ISAs will no longer be permitted, although transfers from a Cash ISA into a non-cash ISA will remain possible. Some cash-like investments can still form part of a diversified non-cash ISA, but a portfolio made up entirely of money market funds will not qualify.

Think clearly: The charge applies to interest on uninvested cash inside a non-cash ISA — not to dividends, capital gains or the value of qualifying investments held in the ISA.

A push towards investing — or a penalty for caution?

The government’s case is that too much long-term cash sits in accounts designed for investing, and that savers may achieve better long-term returns by accepting appropriate investment risk. FT Adviser, however, reports industry criticism that the change could do more harm than good by making ISAs harder to understand and penalising legitimate cash holdings used for fees, withdrawals or temporary risk management.

Both views deserve scrutiny. Cash held for years inside an investment account may miss growth opportunities, but cash can also be a sensible short-term part of a plan. A person moving towards retirement may deliberately reduce risk before drawing an income. Someone new to investing may subscribe first and invest gradually. Rules intended to prevent avoidance should not be mistaken for proof that every cash balance is inappropriate.

The savings reality behind the policy

The reform also lands in a country where many households have not yet built a robust cash cushion. The Money Charity reports that 46 per cent of households had no savings or less than £1,500 in 2024–25. Its June 2026 statistics also show average May rates of 1.99 per cent for instant-access savings and 2.05 per cent for variable-rate Cash ISAs.

For those households, the first priority may be accessible emergency savings rather than maximising the £20,000 ISA allowance. Encouraging investment is worthwhile, but it should sit on top of financial resilience — not replace it.

What to review before April 2027

If you hold cash in a Stocks and Shares ISA, ask what job it is doing. Is it waiting to be invested, reserved for near-term withdrawals, covering platform fees, or simply left there by default? The answer matters more than the headline.

Review provider communications, because firms may change how they display cash, credit interest or collect the 22 per cent charge. Think carefully before moving money solely to beat a rule change: transfers, withdrawals and reinvestment can have consequences, and the technical legislation is still subject to consultation before regulations are laid.

This article provides general guidance, not a recommendation to invest, remain in cash, transfer an ISA or choose a particular product.

Think clearly. Break through the jargon.

References

1. HM Revenue & Customs. “ISA reform 2027: anti-circumvention rules factsheet.” 23 June 2026.
2. FT Adviser. “ISA tax change likely to do more harm than good.” 16 July 2026.
3. The Money Charity. “The Money Statistics.” June 2026.