Important information - the value of investments and the income from them can go down as well as up, so you may get back less than you invest.
What does a million-pound ISA actually look like?
You might be picturing a portfolio packed with winning stocks and high-risk bets on the next big thing, but the reality is rather different. We’ve crunched the numbers to see how our ISA millionaires invest - and what we can learn from their success.
What building blocks do they use?
Where you invest your money is important. But how you invest matters too. Do you want to hold individual companies? Or pool your money with other people’s, spreading your risk across a range of assets?
Personal investors have four main choices: funds, shares, exchange-traded funds (ETFs) and investment trusts.
ISA millionaires have a strong preference for funds. When we totted up the total value of their holdings, funds accounted for more than 80% of the combined assets. This dwarfs the amounts held in ETFs, investment trusts and stocks. It also debunks some common narratives: that you have to be a stock-picking expert to invest successfully, or spend your time day-trading ETFs.
That said, data from the past five years shows ETFs are growing increasingly popular. Unlike traditional funds, which are priced once a day, ETFs trade on a stock exchange. This means the prices of ETFs fluctuate throughout the day when the market is open, based on supply and demand.
Meanwhile, some of the biggest ISA portfolios are invested almost entirely in individual stocks. DIY investors can be very tempted by this approach, but it requires skill and diligence - and could leave you exposed to the fortunes of a small group of companies.
What are their funds invested in?
So, we know that ISA millionaires like open-ended funds. But what are these funds invested in?
Tastes are remarkably varied. Portfolios contain everything from world trackers to specialist vehicles investing in space, gold and agriculture. Collectively, though, global funds dominate, accounting for about a fifth of assets owned by all ISA millionaires. Their popularity may reflect a desire for ready-made geographical diversification.
There are also signs of home bias. UK-focused funds account for over a fifth of total fund assets, putting them comfortably ahead of North America. That doesn't tell the whole story, though: US companies will also make up a substantial proportion of most global funds, so exposure to the region is likely to be considerably higher.
Before drawing too many conclusions, it is also worth remembering that becoming an ISA millionaire is not only about investment selection. Time in the market, regular contributions and the power of compounding are also likely to have played a major role in building these portfolios.
How many investments do they hold?
What is the right number of investments to hold in your ISA? Too many, and you risk complication and unnecessary fees. Too few, and your portfolio might be too concentrated. There is no magic number.
On average, ISA millionaires hold 18 investments, spread across funds, stocks, investment trusts and ETFs. When you break down the numbers, this equates to between one and two funds per £100,000.
Averages do not do justice to the huge variety of approaches on display, however. Some ISA millionaires hold just two funds. Others have almost 600 holdings, consisting mainly of individual stocks.
What are their favourite funds and stocks?
Consistent contributions and compounding do a lot of the heavy lifting in investing. Choosing the right investments is also key to success, however. As such, we have tracked down the 10 favourite funds and stocks of ISA millionaires in 2026.
Top 10 ISA millionaire funds
- Fidelity Global Special Situations Fund
- Fidelity Special Situations Fund
- Legal & General UK Index Trust Fund
- Fidelity Index World Fund
- Legal & General Global Technology Index Trust
- Fidelity Index UK Fund
- Fidelity European Fund
- Legal & General US Index Trust
- Fidelity Index US Fund
- Legal & General European Index Trust
Top 10 ISA millionaire stocks
Source: Fidelity International. Based on total asset values for Fidelity Personal Investors holding at least £1m in their portfolio between January and July 2026.
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Important information - investors should note that the views expressed may no longer be current and may have already been acted upon. Overseas investments will be affected by movements in currency exchange rates. Reference to specific securities should not be construed as a recommendation to buy or sell these securities and is included for the purposes of illustration only. This information is not a personal recommendation for any particular investment. If you are unsure about the suitability of an investment you should speak to one of Fidelity’s advisers or an authorised financial adviser of your choice.
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