New ISA Tax Sparks Backlash From Financial Experts

A new tax on interest earned from cash held within stocks and shares Individual Savings Accounts (ISAs) has drawn sharp criticism from financial experts, who argue it undermines the core tax-free benefits of the savings vehicles and introduces undue complexity.

The measure, set to take effect from April 6, 2027, will impose a 22% charge on interest earned from cash parked in stocks and shares ISAs. The government's stated aim is to encourage greater investment in the stock market and stimulate the country's economy by preventing savers from holding large sums of cash tax-free within these accounts. Under the new rules, savers under 65 will be limited to depositing a maximum of £12,000 into a cash ISA, with any additional funds needing to be invested in stocks and shares.

Financial professionals have voiced strong objections to the policy. Jason Hollands of BestInvest described the charge as a "barely disguised stealth tax" that erodes the tax-free promise of ISAs. He argued that the measure is "overkill" and penalizes investors for holding cash, which can be a sensible strategy for various reasons, including waiting for investment opportunities, managing dividends, or hedging against market volatility. Hollands noted that while proposals to clamp down on "cash-like" investments such as money market funds were less severe than initially feared, the broader levy adds unnecessary complexity.

Holly Mackay of Boring Money criticized the move as the Treasury "cutting its nose off to spite its face." She pointed to data suggesting that 42% of cash-only savers prioritize simplicity when choosing financial products. Mackay contended that the ISA system, which already has complex variants and contribution rules, will become even more confusing with different terms, levies, and qualifying product rules.

Tom Selby from AJ Bell stated that the 22% charge was neither a necessary intervention nor an inevitable outcome of limiting cash ISA allowances. He believes it "muddies the tax-free Isa promise" that has been a cornerstone for investors. Selby suggested alternative approaches, such as preventing ISAs from being marketed as cash vehicles or allowing tax-free cash holdings for genuine investment purposes, would have been more targeted.

Rachael Griffin of Quilter echoed concerns that the changes risk "throwing the baby out with the bathwater." While acknowledging the need to address the UK's reliance on cash savings, she argued that the added complexity comes at a particularly challenging time. Griffin highlighted that a flat-rate charge reduces returns in a way that may be difficult for consumers to grasp and could create broader uncertainty. She warned that if consumers no longer clearly understand the benefits of ISAs, it could deter engagement altogether, an outcome she deemed "poor and clearly unintended."