Share your opinion and earn yourself a free Motley Fool premium report!

We are looking for Fools to join a 75 minute online independent market research forum on 15th / 16th December.

To find out more and express your interest please click here

FTSE 250: Here’s how long it could take for you to become an ISA millionaire

The FTSE 250 (INDEXFTSE:UKX) could offer an appealing growth outlook, in my opinion.

The content of this article was relevant at the time of publishing. Circumstances change continuously and caution should therefore be exercised when relying upon any content contained within this article.

You’re reading a free article with opinions that may differ from The Motley Fool’s Premium Investing Services. Become a Motley Fool member today to get instant access to our top analyst recommendations, in-depth research, investing resources, and more. Learn More.

The time it takes to become an ISA millionaire clearly depends to at least some extent on how much is invested per year. Since the annual allowance has been gradually increased over recent years, so that it now stands at £20,000, it may now be an easier goal for some investors.

However, where an ISA is invested may make a much greater difference to the long-term performance of an ISA than many investors realise. Certainly, investing in shares as opposed to other assets such as cash and bonds can lead to higher returns in the long run. But so too can investing in mid-cap shares instead of large-cap stocks.

High return prospects

While many investors choose to focus their portfolios on larger companies, targeting mid-caps can prove to be a worthwhile move. In many cases, they have greater scope to grow. This can mean they’re able to deliver faster share price increases over the long run, having the potential to expand into new territories and move into new markets more easily than their larger peers.

At present, mid-caps may offer even greater return potential than their larger peers. The FTSE 250, for example, generates the majority of its income from companies that operate in the UK. This means there may be wider margins of safety on offer than in the FTSE 100, where the majority of revenue is generated outside of the UK. Since the UK’s political and economic future appears to have caused investors to become somewhat cautious, there may be better-value investment opportunities among mid-cap shares.

Track records

The FTSE 250’s historic performance has been significantly better than that of the FTSE 100. In the last decade, for example, mid-caps have posted an annualised total return of over 13%. The FTSE 100’s total annual return over the same time period has been around 9%.

That maybe somewhat surprising to many investors, since the world economy has enjoyed a period of strong growth. By contrast, the UK economy has faltered to some degree in the last few years, with business, investor and consumer confidence seemingly coming under pressure following the EU referendum.

Millionaire potential

Clearly, the total annual returns of the last decade have been influenced by the global bull market which has lifted equities across the world. In the last 20 years, which includes the financial crisis and dot com bubble, the FTSE 250 has recorded an annualised total return of around 9%. This is perhaps a more realistic guide for future returns in the long run.

Assuming an investor uses up their ISA allowance each year and generates a 9% return per annum, they could become a millionaire within 20 years. Investing £10,000 per year would extend that period to 27 years, while someone who invests £5,000 per year into the FTSE 250 may become a millionaire within 35 years.

As such, becoming an ISA millionaire could be more realistic than many investors realise. By investing in faster-growing shares over the long run, it may be possible to enjoy financial freedom in retirement.

Views expressed on the companies mentioned in this article are those of the writer and therefore may differ from the official recommendations we make in our subscription services such as Share Advisor, Hidden Winners and Pro. Here at The Motley Fool we believe that considering a diverse range of insights makes us better investors.

More on Investing Articles

Rolls-Royce's Pearl 10X engine series
Investing Articles

Can the Rolls-Royce share price do it again in 2026?

Can the Rolls-Royce share price do it again? The FTSE 100 company has been a star performer in recent years…

Read more »

Businessman hand flipping wooden block cube from 2024 to 2025 on coins
Investing Articles

After huge gains for S&P 500 tech stocks in 2025, here are 4 moves I’m making to protect my ISA and SIPP

Gains from S&P tech stocks have boosted Edward Sheldon’s retirement accounts this year. Here’s what he’s doing now to reduce…

Read more »

View of Lake District. English countryside with fields in the foreground and a lake and hills behind.
Investing Articles

With a 3.2% yield, has the FTSE 100 become a wasteland for passive income investors?

With dividend yields where they are at the moment, should passive income investors take a look at the bond market…

Read more »

Smart young brown businesswoman working from home on a laptop
Investing Articles

Should I add this dynamic FTSE 250 newcomer to my Stocks and Shares ISA?

At first sight, a UK bank that’s joining the FTSE 250 isn’t anything to get excited by. But beneath the…

Read more »

Investing Articles

£10,000 invested in BT shares 3 months ago is now worth

BT shares have been volatile lately and Harvey Jones is wondering whether now is a good time to buy the…

Read more »

Person holding magnifying glass over important document, reading the small print
Investing Articles

After a 66% fall, this under-the-radar growth stock looks like brilliant value to me

Undervalued growth stocks can be outstanding investments. And Stephen Wright thinks he has one in a company analysts seem to…

Read more »

Content white businesswoman being congratulated by colleagues at her retirement party
Investing Articles

Don’t ‘save’ for retirement! Invest in dirt cheap UK shares to aim for a better lifestyle

Investing in high-quality and undervalued UK shares could deliver far better results when building wealth for retirement. Here's how.

Read more »

Black woman using smartphone at home, watching stock charts.
Investing Articles

1 growth and 1 income stock to kickstart a passive income stream

Diversification is key to achieving sustainable passive income. Mark Hartley details two broadly different stocks for beginners.

Read more »