Savers who hold cash inside a stocks and shares ISA will be charged a flat 22% tax on the interest it earns from April 2027, under reforms HM Revenue and Customs set out in a tax policy paper on 23 June.
Who gets caught is the part that will unsettle many savers. The charge bites only on interest from uninvested cash, yet holding some cash inside an investment account is routine. People leave money there while waiting to buy shares, after selling a holding, or to cover platform fees. From April 2027, the interest on those balances becomes taxable, so the rule can reach ordinary investors as readily as anyone deliberately sidestepping the limits.
