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

Stop saving and start investing! How the FTSE 100 could turn £100 per week into a £1m ISA

I think the FTSE 100 (INDEXFTSE:UKX) offers strong long-term growth potential.

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.

Investing £100 per week and ending up with a seven-figure portfolio may sound like a pipe dream to most people. However, it could be a much more attainable goal than it first seems due to the long-term growth potential of the FTSE 100.

By investing in a range of large-cap shares, holding them over the long run and reinvesting your dividends, you could end up with a £1m+ portfolio. By contrast, investing in a Cash ISA or savings account may mean that you experience disappointing returns that fail to improve your long-term financial situation.

FTSE 100 potential

The FTSE 100’s total annual returns since its inception 36 years ago have been around 9%. Assuming a similar rate of growth in future, a £100 investment in the index could be worth over £1m over a 34-year period. This assumes that dividends are reinvested, and that no capital is withdrawn from your portfolio.

With the FTSE 100 currently appearing to offer good value for money, its future returns could prove to be relatively impressive. For example, it has a dividend yield of 4.4%, which is above its long-term average, while major sectors such as resources, energy and financial services appear to offer many stocks that trade on low ratings compared to their historic averages. Over the long run, those valuations may revert towards their averages, which may lead to higher returns for investors in the FTSE 100.

Cash prospects

While the FTSE 100 could catalyse your portfolio’s performance, holding cash or investing in a Cash ISA may not. At the present time, savers may struggle to obtain an income return above 1.5%. Assuming such a rate of return over the same 34-year period discussed above, paying £100 per week into a savings account would lead to a total balance of £228,000.

Clearly, there is scope for interest rates to rise over the coming decades. But history shows that cash returns have lagged the stock market’s returns, due to the lower risk of cash, which may mean that a higher regular investment than £100 per week is required to generate a £1m+ portfolio.

Risk/reward

While the FTSE 100 is a riskier place to invest compared to cash, investors with a long-term outlook are likely to have sufficient time to enable their short-term paper losses to recover. This could mean that, while holding a modest amount of cash for emergencies is a sound move, focusing your capital on the FTSE 100 is a better idea when it comes to improving your long-term financial situation.

Of course, buying high-quality shares while they trade at low prices could enable you to beat the FTSE 100 and generate even higher returns. This could shorten the amount of time it takes to produce a £1m+ portfolio, and may lead to greater financial freedom in older age.  

Peter Stephens has no position in any of the shares 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

Black woman using smartphone at home, watching stock charts.
US Stock

I asked ChatGPT for the juiciest growth share for 2026, and it said…

Jon Smith is rather unimpressed with the growth share that ChatGPT presents to him, and explains his reasons why in…

Read more »

Two business people sitting at cafe working on new project using laptop. Young businesswoman taking notes and businessman working on laptop computer.
Dividend Shares

Here’s a stock lurking in the FTSE 100 with a 9% dividend yield forecast

Jon Smith highlights a FTSE 100 company that he thinks has been in the headlights for share price growth recently…

Read more »

Bus waiting in front of the London Stock Exchange on a sunny day.
Investing Articles

Could a 2026 stock market crash be on its way?

Will the stock market crash next year? Nobody knows for sure, including our writer. Here's what he's doing now to…

Read more »

Thoughtful man using his phone while riding on a train and looking through the window
Investing Articles

How much do you need in an ISA to target a £5,555 monthly passive income?

Muhammad Cheema explains how an investor could target £5,555 in monthly passive income over time by making use of a…

Read more »

Little girl helping her Grandad plant tomatoes in a greenhouse in his garden.
Investing Articles

With single-digit P/E ratios, here are 3 of the FTSE 100’s cheapest-looking shares!

Only a few FTSE 100 shares are trading at single digit-multiples of earnings! And our Foolish author has highlighted what…

Read more »

Friends at the bay near the village of Diabaig on the side of Loch Torridon in Wester Ross, Scotland. They are taking a break from their bike ride to relax and chat. They are laughing together.
Investing Articles

How much do you need in an ISA to earn a £33,333 passive income?

Discover how to target a five-figure passive income in a Stocks and Shares ISA -- and a top 7.6%-yielding dividend…

Read more »

Tariffs and Global Economic Supply Chains
Investing Articles

Did Donald Trump just deliver fantastic news for Nvidia stock?

With artificial intelligence chip sales set to resume in China, is Nvidia stock worth looking at while it's trading under…

Read more »

A rear view of a female in a bright yellow coat walking along the historic street known as The Shambles in York, UK which is a popular tourist destination in this Yorkshire city.
Market Movers

£20,000 of British American Tobacco shares could generate dividends of…

British American Tobacco shares are tipped to deliver more huge dividends over the next three years. Does this make them…

Read more »