As the new UK tax year 2025–26 begins, many savers are setting financial goals. One of the most exciting? Becoming an ISA millionaire.
Today, there are nearly 5,000 ISA millionaires in Britain. The top 25 investors have average pots of £8.8 million, according to a recent report in The Telegraph. With the right strategy and patience, it’s a goal anyone can aim for.
So, how can you become an ISA millionaire? Experts share four clear steps to help you reach that seven-figure milestone.
Step 1: Maximise Your ISA Contributions Every Year
The annual ISA allowance for the 2025/26 tax year is £20,000. To build serious wealth, you should try to use your full allowance every year. The more money you put in early, the more time it has to grow.
Sarah Coles of Hargreaves Lansdown says the most successful investors max out their ISA early in the tax year, giving their investments more time to grow.
Even if you can’t contribute the full amount, consistently investing whatever you can each year adds up over time.
Step 2: Diversify Your Investments
Many ISA millionaires invest in stocks and shares, investment trusts, or funds. Diversification helps reduce risk while still aiming for strong returns.
Laura Suter, head of personal finance at AJ Bell, says some ISA millionaires hold just a few focused investments, but many others prefer to spread their money across different companies, sectors, and regions.
You don’t need to be a stock expert—funds and trusts can offer access to professional management and a variety of companies.
Step 3: Review and Rebalance Regularly
To grow your ISA over time, you should review your portfolio at least once or twice a year. Make sure your investments are still aligned with your financial goals and risk tolerance.
Rajan Lakhani from Plum says that even though other savings products may be losing shine, ISAs remain popular because they’re flexible and liquid, meaning you can access your money when needed.
Don’t panic over market drops, but stay updated and adjust if needed.
Step 4: Stay Invested for the Long Term
Becoming an ISA millionaire doesn’t happen overnight. Most ISA millionaires are in their 60s and 70s, showing the power of long-term compounding.
Still, nearly 20% reached the milestone before turning 60, and a few have built portfolios worth over £3 million in their 40s by following a high-conviction strategy.
That said, you don’t need to take big risks. As Sarah Coles explains, ISA millionaires focus on steady investing and long-term discipline, not chasing short-term gains.
There’s no magic formula to becoming an ISA millionaire. But with regular contributions, smart investing, and patience, it is possible.
Whether you’re starting now or already on your journey, focus on consistency, diversification, and long-term planning. Even if you don’t hit £1 million, you’ll still build a strong financial future by using your ISA wisely.
FAQ’s
What is an ISA millionaire?
An ISA millionaire is someone who has built a portfolio of £1 million or more inside their Individual Savings Account (ISA), using tax-free growth and compounding returns over the years.
How can I become an ISA millionaire?
To become an ISA millionaire, invest your full annual allowance (£20,000), diversify your investments, review your portfolio regularly, and stay invested for the long term.
What types of investments do ISA millionaires hold?
ISA millionaires commonly invest in stocks and shares, investment trusts, and diversified funds. Some follow high-conviction strategies, while others prefer a broad mix.
How long does it take to become an ISA millionaire?
Most ISA millionaires reach this goal in their 60s or 70s, but some manage it earlier through disciplined investing and consistent contributions.
Is it risky to invest in a Stocks and Shares ISA?
All investments carry risk, but many ISA millionaires use diversified portfolios to manage risk. It’s important to invest in what you understand and are comfortable with.
