How I’d invest £25k in a Stocks and Shares ISA to make a million

With a sum like £25k, you can do something great. Here’s how I’d proceed.

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.

£25k is a decent pile of cash, and if you suddenly find yourself in possession of such a sum, you have a shot at doing something great with it.

And the great thing I’d try to do would be to turn it into £1m. With that amount of money, I’d really have some options!

Two important factors

To make the money work hard for me I’d aim to compound the returns it earns. Two factors would influence the eventual outcome. Firstly, the annualised percentage return I can achieve, and the higher the better. Little differences in that percentage can make big differences to the final sum over time.

And time itself is the second factor. The longer I can earn those annualised returns, the bigger the compounded sum will become. And because compounding works exponentially with accelerating returns over time, the biggest absolute returns will arrive in the later years. You could be amazed by how much you’re earning on your investments each year after a few decades of consistent compounding.

So, I’m looking for high annualised returns and a long investing period. And I know that, historically, the highest returns among all the major asset classes have come from stocks and shares. Over the long haul, shares have outpaced things such as cash savings, bonds, property and commodity prices.

Tax-efficient wrappers

It’s shares and share-backed investments all the way, for me. But where should you start? I’d begin by considering the tax advantages of investing in a Stocks and Shares ISA and pension schemes such as a Self-Invested Personal Pension (SIPP). Such ‘wrappers’ can make a good home for your investments.

Pensions, for example, boost your money on the way in because the tax relief on your pension contributions means the money you would have paid in tax on your earnings goes into your pension pot rather than to the government. And ISA accounts allow you to withdraw the money in the end without being taxed on it, so it’s tax relief on the way out.

Capturing stock market returns

To capture the returns available from the stock market you could invest in managed funds, which are run by an investment manager or a team of professionals who aim to beat their benchmark with their share picking. But the ongoing fees can be quite high and there’s no guarantee that the fund’s performance will be any good. Sometimes it can be disastrous, such as with the Woodford funds recently.

You could go down the passive index tracker route. These are low-cost funds that mechanically aim to mimic the returns of indices such as the FTSE 100, FTSE 250, S&P 500 and many others. And you could also aim to juice up your overall returns with some careful individual share picking of your own.

I reckon it would be a reasonable strategy to spread your £25k between active funds, passive funds, and individual shares as long as you avoid speculative and high-risk investments of all kinds. Remember, if you lose it, you can’t compound it!

Kevin Godbold has no position in any share mentioned. The Motley Fool UK has no position in any of the shares mentioned. 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

British pound data
Investing Articles

The red lights are flashing again for Lloyds’ share price! Here’s why

Lloyds' share price continues to defy gravity. But Royston Wild thinks it's only a matter of time before the FTSE…

Read more »

Aston Martin DBX - rear pic of trunk
Investing Articles

Aston Martin shares are now only 41p!

Aston Martin shares just dropped to around the 41p mark! Is this a brilliant buying opportunity or a stock that…

Read more »

Artillery rocket system aimed to the sky and soldiers at sunset.
Investing Articles

Up 325% in 5 years! But are BAE System shares still a no-brainer buy?

BAE Systems shares would have been a brilliant buy five years ago. But could they still offer excellent returns if…

Read more »

Investing Articles

How much do you need to invest each month into FTSE 100 shares to aim for a million?

Simply by putting a few hundred pounds a month into FTSE 100 shares, how might someone aim to become a…

Read more »

Close-up as a woman counts out modern British banknotes.
Investing Articles

£10,000 invested in BAE shares at the beginning of 2026 is now worth…

Paul Summers tips his hat to those who invested in BAE Systems shares when markets opened back up in January.…

Read more »

A senior man and his wife holding hands walking up a hill on a footpath looking away from the camera at the view. The fishing village of Polperro is behind them.
Investing Articles

What size ISA do you need for £250-a-week retirement income?

Harvey Jones outlines the advantages of investing in a Stocks and Shares ISA rather than leaving money in cash, and…

Read more »

Mature Caucasian woman sat at a table with coffee and laptop while making notes on paper
Investing Articles

£5,000 invested in Legal & General shares 5 years ago is now worth…

Harvey Jones crunches the numbers to show how much an investor would have earned from Legal & General shares lately,…

Read more »

Investing Articles

Just check out the latest bumper forecasts for Lloyds, NatWest and Barclays shares

Harvey Jones says Barclays shares have had a terrific year and there could be more action to come. So what's…

Read more »