There are more than 5,000 ISA millionaires in the UK – savers who have built up seven-figure sums in their tax-free accounts. While reaching that milestone may not happen overnight, it is achievable over time, even for those investing modest amounts.
Individuals can put up to £20,000 a year into an ISA, either in cash or investments, with all gains tax-free. To reach millionaire status, investing in the stock market is key, as it historically offers higher returns than cash savings. According to Murphy Wealth, 94 per cent of ISAs worth £1 million or more are stocks and shares ISAs.
Someone investing the full £20,000 annual allowance each year could become an ISA millionaire in 22 years, assuming annual returns of 6 per cent. Investing £1,000 a month would take 30 years, while £500 a month would take 40 years. The average ISA millionaire is 73 years old, with 67 per cent male, and holds 41 per cent in investment trusts, 35 per cent in individual shares, and just 5 per cent in cash, according to Interactive Investor.
To start, open a stocks and shares ISA, comparing fees, regulation, reviews, and investment options. Setting up a regular investing plan via direct debit is a good habit. The earlier you start, the more you benefit from compound interest, where returns generate further returns. For example, someone investing £4,400 a year from age 20, increasing contributions by 2 per cent annually, could reach £1 million by 65 with 5 per cent annual returns. Starting at 30 would require £8,200 in the first year, and at 40, £16,400.
Popular investments among ISA millionaires include Alliance Witan (up 40 per cent over three years to November 2025) and Scottish Mortgage (up 47 per cent), along with shares in Legal & General, Aviva, BP, National Grid, and Shell.
