Number of ISA millionaires reaches a new record

The UK now has almost 8,000 ISA millionaires, helped by historic stock market returns and investors who stayed the course. Could you join them?

?

In the latest tax year, the number of people with at least 1 million in their ISAs rose to a record 7,730.

Figures obtained by savings and investment app Plum through a Freedom of Information (FOI) request to HMRC show that the number of ISA millionaires rose by more than 50% in the 2023/24 tax year, up from 5,070 the year before.

The average ISA millionaire now holds 1,348,000 - almost unchanged from 2022/23 - even though more than 5,000 additional people have reached millionaire status.

ISA millionaires have become more numerous. Among them, 320 people hold between 2 million and 3 million, while 40 have between 3 million and 4 million and 60 hold more than 4 million.

Among the 40 investors whose pots exceeded 4 million, the average account held 7,708,000. For the top 25 ISA investors in the UK, that average rose to just under 12 million.

Money held in an ISA does not incur capital gains or dividend tax, so portfolio growth avoids a potentially large tax bill. A 1 million portfolio rising by 15% - the S&P 500's average return over the last 10 years - would produce 150,000 in tax-free gains.

Bryant added: "These investors didn't reach Millionaires' Row by selling whenever markets turned frightening. They stayed invested through financial crises, Covid, rising interest rates and tariff worries - all of it.

"It's harder than it sounds to remain invested. But time in the market, rather than trying to time the market, is what works. This data proves it."

Are there any cash ISA millionaires?

In theory, yes. Someone who had deposited the full 20,000 ISA allowance into cash every year since 1999 could have reached 1 million, but that outcome is extremely unlikely.

Most ISA millionaires built their wealth by investing their contributions in the stock market. Cash alone did not get them there: a separate FOI request that Murphy Wealth sent to HMRC in 2025 found that, during the 2021/22 tax year, not one ISA millionaire reached that level using only cash ISA holdings.

The research found that 94% of ISA millionaires in the UK built their wealth solely through stocks and shares ISAs. The other 6% used both cash ISAs and stocks and shares ISAs.

How can you become an ISA millionaire?

Becoming an ISA millionaire may sound out of reach, but patient investors who contribute regularly could get there sooner than expected.

Plum's figures suggest that someone starting today with no existing savings could reach ISA millionaire status in about 22 years by investing the full 20,000 annual allowance in a stocks and shares ISA, assuming annualised returns of 7% after fees.

Investors aiming to reach 1 million in their ISA should remember that patience is essential.

Charlene Young, AJ Bell's head of technical, said ISA millionaires show what may happen when investors contribute regularly, give their money time, remain patient - and perhaps get a little lucky.

To reach 1 million in an ISA, she said, investors need to think in terms of getting rich slowly and begin as early as they can.

Younger people willing to take substantial risks may sometimes earn exceptional returns. For most ordinary investors, though, the sounder approach is a diversified portfolio held over many years.

When it comes to choosing investments, Young says there's no single path to becoming an ISA millionaire.

An analysis of AJ Bell's ISA millionaires found that many favour shares and investment trusts, though plenty also invest through funds. What matters is choosing investments you understand and accepting the risk attached to the possible return.