Could you become an ISA millionaire by 2031?

Hargreaves Lansdown says the number of ISA millionaires on its platform has increased by almost 700% over the past seven years. We reveal the top funds they invested in and how you could reach millionaire status by 2031.

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(Image credit: Oscar Wong via Getty Images)

The number of people with more than a million pounds in their individual savings account (ISA) is booming, helped by strong stock market performance last year.

Hargreaves Lansdown reported having 1,322 ISA millionaires on its platform at the end of December 2024 – 14% higher than six months ago, and more than double compared to two years ago.

Meanwhile, there were just 168 ISA millionaires in 2017, meaning the figure is up almost 700% compared to seven years ago.

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This begs the question: how many more ISA millionaires will there be by 2031 and could you become a member of the rapidly-growing club? With an annual ISA limit of £20,000, the only way you will be joining the club by 2031 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 72, the youngest ISA millionaire with Hargreaves Lansdown is just 27 years old.

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.

We look at the top funds and stocks that ISA millionaires have been putting into their portfolios and how long it could take you to hit a million.

Where are ISA millionaires investing?

The most popular investments with ISA millionaires in 2024 were blue-chip companies, including a good mix of dividend stocks.

The average age of the club could partly explain this preference, with older investors often seeking dividend income to support them in retirement.

Most ISA millionaires are long-term investors rather than speculators – Marshall says the group is not in a hurry to trade its investments regularly.

She adds: “When it comes to the top 10 most bought funds, ISA millionaires have invested in a broad international mix of popular funds. Half were focused on a diversified mix of global companies, but there are also a couple of UK funds, including an income fund.”

Most popular shares with ISA millionaires

  • Legal & General Group
  • Phoenix Group Holdings
  • Aviva
  • IG Group Holdings
  • Intercede Group
  • Beeks Financial Cloud Group
  • BP
  • Rio Tinto
  • M&G
  • Michelmersh Brick Holdings

Most popular funds with ISA millionaires

  • Legal & General Global Technology Index Trust
  • Legal & General US Index
  • Legal & General International Index Trust
  • Jupiter India
  • Artemis Income
  • WS Blue Whale Growth
  • Rathbone Global Opportunities
  • Legal & General UK 100 Index Trust
  • Legal & General European Index
  • Fidelity Index World

How long does it take to become an ISA millionaire?

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 grow even more than this. In 2024, the S&P 500 grew by more than 23% based on price returns.

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 2031 (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.

Katie Williams
Staff Writer

Katie has a background in investment writing and is interested in everything to do with personal finance, politics, and investing. She enjoys translating complex topics into easy-to-understand stories to help people make the most of their money.

Katie believes investing shouldn’t be complicated, and that demystifying it can help normal people improve their lives.

Before joining the MoneyWeek team, Katie worked as an investment writer at Invesco, a global asset management firm. She joined the company as a graduate in 2019. While there, she wrote about the global economy, bond markets, alternative investments and UK equities.

Katie loves writing and studied English at the University of Cambridge. Outside of work, she enjoys going to the theatre, reading novels, travelling and trying new restaurants with friends.