Daniel Hilton
Becoming an ISA millionaire 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.
The first step is to start investing like one. ISA millionaires are often astute investors who know and apply their investment fundamentals when managing their money.
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For example, many of them have a strong understanding that investing in their ISAs regularly and early can help boost their long-term returns.
In other words, they are a “keen bunch,” as Victoria Hasler, head of fund research at Hargreaves Lansdown, puts it.
It will likely 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
Investing early each tax year is undoubtedly one of the best moves you can make to give yourself the best chance of maximising returns.
Almost a third (30%) of Hargreaves Lansdown's 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.
Recent research shows early-bird ISA investors are £34,000 better off over a decade compared with those who wait until the last minute to invest their full £20,000 ISA allowance.
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.
“When they got their new ISA allowance at the start of the year, many took advantage of it straight away to get investing in a tax-efficient manner,” says Hasler.
“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,” she added.
This is also supported by the fact that just 2% of ISA millionaires invested in the last week of the 2024/25 tax, 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 new tax year were blue-chip companies, including a good mix of dividend stocks.
The average age of the club could partly explain this preference. Last year, HL reported that the average ISA millionaire was 74. Older investors often seek dividend income to support them in retirement.
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.
She also draws attention to the fact that a UK government bond (gilt) was the seventh-most popular investment with ISA millionaires, saying it is “perhaps a sign of the times that investors are looking to less risky investments.”
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.
This attitude towards risk carries across to other investment platforms with Ed Monk of Fidelity saying that “anyone that’s built a million pounds in their ISA probably won’t be phased by a bit of turbulence in markets.”
However, where Fidelity’s ISA millionaires differ from HL’s is in the location of their investments.
While HL’s ISA millionaires have taken more of a liking towards UK funds and stocks, Fidelity’s still have a strong bias towards US stocks.
So far in 2025, six of the 10 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.
Most popular funds with Fidelity’s ISA millionaires (4 April 2025)
- 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
How many ISA millionaires are there?
The number of people with more than a million pounds in their ISA is booming.
Hargreaves Lansdown reported having 1,243 ISA millionaires on its platform at the end of December 2024 – 14% higher than six months prior, and more than double compared to 2022.
Meanwhile, there were just 168 ISA millionaires in 2017, meaning the figure is up almost over 600% over the past seven years (2017-2024). This raises the question: could you be an ISA millionaire in seven years' time (2032)?
Could you become an ISA millionaire by 2032?
With the number of ISA millionaires rising so rapidly between 2017 and 2024 (a period of seven years), it 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.
Although the average age of a member of the club is 74, the youngest ISA millionaire with Hargreaves Lansdown is just 28 years old.
The time it takes to become an ISA millionaire depends on how much you invest each year, and the level of return you manage to achieve.
Let’s assume you maxed out your annual £20,000 ISA allowance every year, investing around £1,666.66 per month.
If you 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. This year has been far tougher, with the S&P 500 down more than 5% so far year-to-date, thanks to US president Donald Trump's trade policy.
Assuming a 5% annual return, you would already need to have a portfolio worth around £592,000 to be in with a chance of becoming an ISA millionaire by 2032 (as well as maxing out your annual allowance each year).
Assuming an 8% annual return, you would already need a portfolio worth around £475,000.
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