An ISA (Individual Savings Account) is a savings account available to UK residents on which the return is tax-free and which need not be declared on the investor’s tax return. All income (dividends and interest) and all capital gains within the account are free of tax. For the current year, 6 April 2024 to 5 April 2025 the overall investment limit is £20,000 (excluding the British ISA which has a separate £5,000 limit).