How a £100 weekly investment in UK shares can become a £1m ISA

Investing modest amounts regularly in UK shares could lead to a surprisingly large ISA portfolio, in my view. It may even lead to a £1m nest egg.

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.

With the State Pension age continuing to rise, investing in UK shares on a regular basis could significantly improve your long-term financial prospects.

The growth outlook for the stock market continues to be relatively positive despite the recent stock market crash. Many FTSE 100 and FTSE 250 shares with improving outlooks trade at low prices that could rise over the long run.

Therefore, now could be the right time to invest £100 per week, or any other amount, in a diverse range of British stocks. Over time, they could improve your retirement prospects and even lead to an ISA valued at £1m.

Starting to buy UK shares early

The earlier you can start buying UK shares, the more time they will have to produce compound returns. For example, the FTSE 100 has returned around 8% per annum on a total return basis over recent decades. An 8% annual return in itself may not sound all that impressive. However, when it’s achieved every year for a prolonged period of time, it can add up to surprisingly large returns.

For example, £100 per week invested in the FTSE 100 at 8% over a 10-year time period could end up being worth around £80,000. While that represents a significant sum of money, the same investment at the same rate of return could be worth as much as £1m over a 35-year time period. As such, the earlier you can start planning for retirement, the more chance there is of obtaining a large portfolio.

Buying cheap stocks

As well as providing your portfolio of UK shares with a long period of time to grow, purchasing cheap stocks may improve your prospects of generating a large nest egg. A key reason for this is that the stock market has always posted strong gains in the years following its declines.

For example, it surged to new record highs after downturns such as the dot com bubble and the global financial crisis. A similar outcome seems likely after the recent market crash.

Therefore, now could be the right time to start building a diverse ISA portfolio of British stocks. Many high-quality companies are currently trading at prices that are significantly below their historic averages. This may mean they can deliver high returns that allow you to outperform the wider stock market.

As a result, you may be able to build a £1m portfolio in a shorter amount of time than the 35 years given in the previous example.

Of course, UK shares are likely to experience periods of uncertainty and high volatility in the short run. For example, Brexit and the US election could cause investor sentiment to change in the coming months.

However, by taking a long-term view and maintaining your regular investment, you can enjoy financial freedom in older age via your generous ISA nest egg.

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

Young woman working at modern office. Technical price graph and indicator, red and green candlestick chart and stock trading computer screen background.
Investing Articles

2 world-class S&P 500 stocks down 11% and 32% to consider buying

Searching for stocks to buy for an ISA in April? Our writher thinks these excellent growth shares are worth a…

Read more »

View over Old Man Of Storr, Isle Of Skye, Scotland
Investing Articles

How much do you need in a Stocks and Shares ISA to aim for an annual income of £39,477?

Harvey Jones shows how ordinary investors can use their Stocks and Shares ISA allowance to build a generous passive income…

Read more »

British flag, Big Ben, Houses of Parliament and British flag composition
Investing Articles

Wise: a hidden gem in the UK stock market

You won’t find Wise on the list of most popular shares in the British stock market. But Edward Sheldon believes…

Read more »

Rear view image depicting a senior man in his 70s sitting on a bench leading down to the iconic Seven Sisters cliffs on the coastline of East Sussex, UK. The man is wearing casual clothing - blue denim jeans, a red checked shirt, navy blue gilet. The man is having a rest from hiking and his hiking pole is leaning up against the bench.
Investing Articles

Is a £100,000 SIPP big enough to retire on?

Harvey Jones looks at how much money investors need in a SIPP to fund a decent standard of living after…

Read more »

British flag, Big Ben, Houses of Parliament and British flag composition
Investing Articles

As the FTSE 100 dips again, here’s what I think smart investors do next

FTSE 100 swings are creating short-term noise — but Andrew Mackie argues this may be where long-term opportunities are quietly…

Read more »

Investing Articles

This 67p growth stock’s smashing the FTSE 100 in 2026

This under-the-radar UK growth stock's absolutely flying right now. But it still sports a very reasonable valuation, says Edward Sheldon.

Read more »

Night Takeoff Of The American Space Shuttle
Investing Articles

Forget SpaceX? Amazon stock offers exposure to space cheaply

Amazon is the best performing Mag 7 stock in 2026. That's because investors are realising that there's huge potential in…

Read more »

Portrait Of Senior Couple Climbing Hill On Hike Through Countryside In Lake District UK Together
Investing Articles

How much does an investor need in an ISA to target £1,500 in monthly passive income?

Paul Summers reckons a bit of commitment and discipline can help generate a wonderful passive income stream for retirement.

Read more »