New ISA Rules Could Mean Tax on Stocks and Shares
Millions of savers with stocks and shares ISAs may now be liable for tax on dividends and capital gains for the first time, following changes to ISA rules that took effect from the start of the 2026-27 tax year. The reforms, announced in the Spring Budget, have significantly reduced the tax-free allowances for dividends and capital gains, meaning many investors who previously paid no tax on their ISA holdings could now face a bill.
What Has Changed?
Previously, all income and gains within an ISA were completely tax-free. However, the government has introduced a new annual allowance of £500 for dividend income from ISA investments and a £3,000 allowance for capital gains. Any income or gains above these thresholds will be taxed at the individual's marginal rate. This marks a major shift in the tax treatment of ISAs, which have been a cornerstone of tax-efficient saving since their introduction in 1999.
The changes apply to all new contributions and any existing holdings in stocks and shares ISAs. Cash ISAs remain unaffected, with interest still tax-free. According to HM Revenue & Customs, approximately 4.5 million people hold stocks and shares ISAs, and the Treasury estimates that around 1.2 million savers will be affected by the new rules.
Impact on Savers
For a basic-rate taxpayer, exceeding the dividend allowance by £1,000 would result in a tax bill of £87.50, while a higher-rate taxpayer would pay £337.50. Capital gains above the £3,000 allowance are taxed at 10% for basic-rate taxpayers and 20% for higher-rate taxpayers. The changes are expected to generate an additional £1.5 billion in tax revenue for the government over the next three years.
Financial experts have warned that the reforms could discourage long-term investing. Sarah Coles, head of personal finance at Hargreaves Lansdown, said: "This is a fundamental change to the ISA regime. For years, ISAs have been a safe haven from tax, but now investors need to be aware that they may have to pay tax on their investments for the first time. It's essential to keep track of dividends and gains to avoid any surprises at tax time."
What Should Investors Do?
Investors are advised to review their ISA portfolios and consider whether they need to adjust their strategies. Options include switching to a cash ISA, which remains tax-free, or using other tax-efficient vehicles such as pensions or venture capital trusts. However, experts caution against making hasty decisions based solely on tax considerations.
The changes do not affect any gains or dividends accrued before April 2026. Investors who are unsure about their tax position should consult a financial adviser or use HMRC's online tools to calculate potential liabilities. The deadline for reporting any taxable income or gains from ISAs is 31 January following the end of the tax year.
