How do ISA millionaires invest – and could you become one by 2032?

Becoming an ISA millionaire – someone with £1 million or more held in ISAs – is probably the dream of many investors who want to make the most of the tax wrapper.

Though it may sound far-fetched, joining this coveted club is not as impossible as some think – provided you are smart with your money.

There were around 4,850 ISA millionaires in the 2021/22 tax year, the most recent year with available data, according to a Freedom of Information request sent to HMRC by wealth manager Murphy Wealth.

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The first step to join this club is to start investing. Of these 4,850 ISA millionaires, 94% (4,560) got to this milestone by using the stocks and shares ISA alone, according to the data.

The remaining ISA millionaires (290) had a combination of both a cash ISA and a stocks and shares ISA which reached or exceeded a value of £1 million when combined.

Not a single ISA millionaire had their wealth stored in a cash ISA alone.

Once you start investing, you will need to adopt the same investment habits as an ISA millionaire. They are often astute investors who know and apply their investment fundamentals when managing their money.

For example, many of them have a strong understanding that investing in their ISAs regularly and early can help boost their long-term returns.

Adrian Murphy, chief executive of Murphy Wealth, said: “Almost all ISA millionaires have built their wealth by holding stocks and shares – and no one has got to that status holding cash alone. It only serves to underline why more people in the UK should consider investing their money.

Some people are put off investing because they perceive the stock market as risky compared to hoarding cash.

“But the reality is quite different,” said Murphy. “Historically, a balanced portfolio of stocks and shares has delivered far higher returns over most reasonable timeframes, while cash savings have often failed to beat inflation.”

It could take years of shrewd investing and discipline in order to become an ISA millionaire, but that is no reason to avoid starting.

We look at how ISA millionaires invest, their favourite funds, and how you could join the club.

How to invest like an ISA millionaire

One of the best moves you can make to maximise your returns is to invest early and keep going at it.

In the context of building up your ISA wealth, this means maximising your ISA limit at the start of each tax year (1 April).

Almost a third (30%) of Hargreaves Lansdown's (HL) ISA millionaires topped up or opened an ISA in just the first two weeks of the 2025/26 tax year.

This was also the case in the previous year, with HL reporting that 34% of ISA millionaires topped their accounts up in the first two weeks of the 2024/25 tax year.

While the timing of your investments may sound like a minimal factor, research by financial advice firm Bowmore Wealth found that investing early pays off in the long term.

They found that ISA investors who maximised their ISA limit at the start of the tax year have earned around £123,000 more than those who waited until the last day of the tax year to invest over the last 20 years.

By investing early, savers allow their investments to make the most of compounding throughout the course of the year, and let their money grow more than if they had invested it at the end of the year.

Victoria Hasler, head of fund research at Hargreaves Lansdown, said: “ISA millionaires know the importance of compounding. They have heard and understood that old investing adage that it’s not timing the market, but time in the market that matters.”

This is also supported by the fact that just 2% of ISA millionaires invested in the last week of the 2024/25 tax, according to HL, with Hasler noting that this shows a level of discipline and good organisation.

Apart from making sure to invest early in the tax year, ISA millionaires also put their money in slightly different investments than other savers.

Where are ISA millionaires investing?

The most popular investments with ISA millionaires in the first weeks of the 2025/26 tax year were blue-chip companies, including a good mix of dividend stocks.

The average age of the club could partly explain this preference. The average age of an ISA millionaire in 2024 was 74 (though the youngest was 28) and older investors often seek dividend income to support them in retirement, according to HL.

ISA millionaires are also more likely to top up or buy active funds than non-millionaires, HL’s research found, with six of the 10 most popular funds being run by active managers.

Of these active funds, four were global, but two, including the most popular fund, were UK-based. Hasler suggests: “Maybe ISA millionaires can now see value in the UK market.”

Other popular investments for ISA millionaires include UK stocks within the FTSE 100.

“There was a preference amongst our ISA millionaires for higher-yielding stocks, consistent with the popularity of income-focused funds,” says Hasler.

Most popular non-fund investments with HL ISA millionaires (7-17 April 2025)

• Comtech Telecommunications
• Legal & General Group plc
• BP Plc
• Hexagon Composites ASA
• AstraZeneca plc
• Shell plc
• Treasury 4.75% 22/10/43 - Gilt
• Genel Energy plc
• GSK plc
• Lloyds Banking Group plc

Most popular funds with HL ISA millionaires (7-17 April 2025)

• Artemis Income
• Legal & General European Index
• Legal & General International Index Trust
• Legal & General Global Technology Index Trust
• Rathbone Global Opportunities
• Legal & General UK 100 Index Trust
• Lindsell Train Global Equity
• Legal & General US Index
• BNY Mellon Global Income
• Artemis Global Income
• Artemis High Income

Furthermore, the investment platform says the majority of its millionaires have taken a measured approach to investing, opting for a well-diversified portfolio rather than making high-risk bets on volatile positions.

“Some people get into investment in the hope of ‘getting rich quick’, but the vast majority of ISA millionaires have built a fortune through the far more reliable approach of getting rich slowly,” says Kate Marshall, investment analyst at Hargreaves Lansdown.

“They don’t necessarily take enormous risks: many consistently invest as much as possible of their annual allowance in a diverse and balanced portfolio, every year, for decades,” she adds.

While HL’s ISA millionaires took a liking towards UK funds and stocks at the start of the tax year, this is not to say that all ISA millionaires think this way.

Indeed, ISA millionaires who use Fidelity’s investment platform favoured funds outside the UK with six of the ten most popular funds purchased by Fidelity’s ISA investors were weighted at least 50% to US stocks, with several also having a strong focus on tech equities.

• Legal & General Global Technology Index Trust
• UBS Global Enhanced Equity Income Fund
• Legal & General Cash Trust
• Fidelity Index US Fund
• Fidelity Multi Asset Open Strategic Fund
• Legal & General Global 100 Index Trust
• Orbis OEIC Global Balanced Fund
• Fidelity Index World Fund
• Fidelity Cash Fund

Could you become an ISA millionaire by 2032?

The number of ISA millionaires has risen rapidly in the last seven years, growing from a base of just 168 in 2017. That raises the question: how many more ISA millionaires will there be seven years from now (2032)?

With an annual ISA limit of £20,000, the only way you will be joining the club by 2032 is if you have started investing already.

Despite this, you might be surprised at how quickly your nest egg grows if you adopt a regular investment habit and take a long-term approach.

Naturally, the time it will take you to become an ISA millionaire will depend on how much you are able to invest each tax year, and the level of return you are able to achieve.

Assuming you max out your annual £20,000 ISA allowance every year, investing around £1,666.66 per month, and achieved an annual growth rate of 5% per year, it would take you 26 years to join the millionaire club, based on figures we plugged into Hargreaves Lansdown’s investment calculator.

By the end of the 26-year period, you would have a portfolio worth £1,049,744. Almost £520,000 of this would have come from your own contributions. Roughly £530,000 would have come from investment growth.

If you managed to achieve an 8% annual return on your ISA portfolio, investing the same monthly amounts as outlined previously, it would take you 21 years to become a millionaire.

Depending on the funds or stocks you decided to invest in, your return could be higher or lower than this amount. Over the long term, the average US stock market return is closer to 10% per year.

Some years, investors will make losses if markets take a downturn but, other years, their investments will experience strong growth. In 2024, the S&P 500 grew by more than 23% based on price returns. In the year to 3 November 2025 the index is up around 16%.

So, to become an ISA millionaire by 2023, would need to already have a portfolio worth around £592,000 and to keep maxing out your £20,000 ISA allowance each year to be in with a chance, assuming a 5% rate of annual growth.

Assuming an 8% annual return, you would already need a portfolio worth around £475,000.