The number of UK investors with Individual Savings Accounts (Isas) worth £1 million or more has tripled over the past three years, hitting around 17,600 by the end of the 2025/26 tax year.
Freedom of Information data indicates that 5,070 individuals held Isa portfolios exceeding £1 million at the start of the 2023/24 tax year. Current figures show 48,160 savers with holdings between £500,000 and £750,000, and 1,210 on the verge at £950,000 to £1 million.
Analysis projects 17,600 Isa millionaires by April 2026, assuming 8% annual investment growth and full use of the £20,000 annual allowance. Higher returns could push the total even further.
Key Growth Drivers
These projections factor in steady saving habits, with near-millionaires crossing the threshold gradually. Historically, Isa millionaire numbers double every three years, tripling when global equity returns top 15%. Since April 2023, MSCI World indices have delivered 17.4% annualized returns, fueling rapid expansion.
Angela Smith, senior investment director at Rathbones, stated: “Our analysis of the data suggests the number of Isa millionaires is likely to have risen significantly over a relatively short period, even on modest assumptions. This means many more investors are now benefiting from tax-free growth, income and dividends on seven-figure portfolios. Our experience with clients shows that the not-so-secret ingredients behind building an Isa millionaire portfolio are patience, time, consistently using allowances, and avoiding interruptions to the power of compounding.”
Even without new contributions after April 2023, 8% returns could elevate the count from 5,070 to 7,100 by April 2024, 9,510 by April 2025, and 13,100 by April 2026. At 5% returns with full allowances, it reaches 12,300; without contributions, 9,300.
This surge stems from compounding in tax-free wrappers, disciplined allowance use, and market gains. However, inflation erodes real value—£1 million today buys what £1.7 million did 20 years ago.
Angela Smith added: “Even after investment gains, £1million is no longer what it used to be. Inflation steadily erodes purchasing power, which is why saving alone is rarely enough. Investing wisely – across assets such as shares and funds – can help deliver returns that outpace inflation and protect and grow wealth over the long term.”
Platform Data Confirms Boom
Investment platforms report sharp increases: AJ Bell saw a 74% rise in millionaire investors over the past year, while Interactive Investor noted a 79% jump in Isa millionaires, from 1,607 to 2,869.
Nearly all (94%) built fortunes via stocks and shares Isas, with 6% mixing in cash. Angela Smith noted: “Many Isa millionaires didn’t sprint their way there – most started out with Personal Equity Plans (Peps) long before Isas existed. They built good habits, avoided common pitfalls, and let time and discipline do the heavy lifting. The not-so-secret ingredient to building a large Isa isn’t perfect timing or extraordinary risk-taking, but patience, time, and iron-clad discipline to keep investing and resist the temptation to tinker unnecessarily.”
Tips to Join the Isa Millionaire Club
Insights from UK pioneers Lord Lee of Trafford, the first Isa millionaire, and Ollie Perry, who reached the milestone at 36, highlight proven strategies.
- Fully utilize your £20,000 allowance: Only 4% of savers max it out, but consistent use accelerates growth. Lord Lee began investing in 1987; Perry maxed his for 11 years from 2013 to 2024.
- Research investments thoroughly: Focus on understood sectors and high-potential stocks. Perry emphasized: “Before you even start to put £10 in an Isa do some research about investments. There’s a lot of value in understanding how stocks have performed, what inflation is and how it erodes the value of money.”
- Reinvest dividends: Compounding via automatic reinvestment buys more shares, boosting long-term returns—a core tactic for Lord Lee.
- Embrace calculated risks: Successes like Lord Lee’s Cerillion (98p to 1,190p since 2016 IPO) or Perry’s early Betfair bet drove outsized gains.
Additional advice: Start early, invest pay rises, avoid breaks, contribute early in the tax year, and align investments with risk tolerance and goals.
