Warning! A Cash ISA can destroy your wealth: here’s why I’d buy FTSE 100 stocks instead

Cash ISA returns could remain below inflation over the medium term, which may make FTSE 100 (INDEXFTSE:UKX) shares more appealing 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 great popularity of Cash ISAs is somewhat surprising. After all, they offer an interest rate that is below the rate of inflation. This means that in the long run any amounts invested in them are losing their spending power.

Furthermore, the tax benefits of a Cash ISA have declined in recent years when compared to bog-standard savings accounts.

As such, an investor may be better off holding a relatively modest amount of cash in a savings account and investing the remainder of their wealth in FTSE 100 stocks instead. This could lead to higher returns, as well as a more efficient use of capital.

Cash appeal

Of course, having some cash at all times is a good idea. It can provide peace of mind, as well as the capacity to pay for exceptional and unexpected items. For example, housing repairs and a loss of employment are events that can occur without prior notice, so having enough cash to cover them in the short run is a worthwhile move.

However, having a significant proportion of your wealth in cash can lead to a disappointing financial outcome in the long run. Put simply, cash is unlikely to deliver a positive real-terms return. As I said, inflation is currently being ahead of the best interest rates that are available on a Cash ISA.

Although there is the potential for interest rates to move higher, historically a tighter monetary policy has often been prompted by a rising inflation rate. This means that on a real-terms basis cash could lead to a reduction in your wealth in the long run due to its returns consistently being behind the rate of inflation.

Stock market appeal

By contrast, the stock market could offer positive real-terms returns in the long run. It has a track record of delivering total returns that are in the high single-digits on an annualised basis, which is likely to be ahead of the inflation rate.

Furthermore, the FTSE 100 appears to offer a wide range of companies that have margins of safety at the present time. A number of stocks – especially those with exposure to the UK economy – have price-to-earnings (P/E) ratios that are below their historic averages. This suggests that they may be able to offer long-term capital growth potential that could produce above-average returns for investors.

Tax changes

While Cash ISAs previously offered significant tax advantages versus a bog-standard savings account, changes in recent years mean that the first £1,000 in interest received outside of a Cash ISA is tax-free.

As such, it may be worth holding cash in a bog-standard savings account, rather than in a Cash ISA. This could mean that you are able to capitalise on the tax efficiencies offered by a Stocks and Shares ISA, which could further enhance your returns in the long run.

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

British bank notes and coins
Investing Articles

Here’s a £30-a-week plan to generate passive income!

Putting a passive income plan into action need not take a large amount of resources. Christopher Ruane explains how it…

Read more »

Close-up of British bank notes
Investing Articles

Want a second income? Here’s how a spare £3k today could earn £3k annually in years to come!

How big can a second income built around a portfolio of dividend shares potentially be? Christopher Ruane explains some of…

Read more »

Close-up of British bank notes
Investing Articles

£20,000 for a Stocks and Shares ISA? Here’s how to try and turn it into a monthly passive income of £493

Hundreds of pounds in passive income a month from a £20k Stocks and Shares ISA? Here's how that might work…

Read more »

Snowing on Jubilee Gardens in London at dusk
Investing Articles

£5,000 put into Nvidia stock last Christmas is already worth this much!

A year ago, Nvidia stock was already riding high -- but it's gained value since. Our writer explores why and…

Read more »

Investing Articles

Are Tesco shares easy money heading into 2026?

The supermarket industry is known for low margins and intense competition. But analysts are bullish on Tesco shares – and…

Read more »

Smiling black woman showing e-ticket on smartphone to white male attendant at airport
Investing Articles

Can this airline stock beat the FTSE 100 again in 2026?

After outperforming the FTSE 100 in 2025, International Consolidated Airlines Group has a promising plan to make its business more…

Read more »

Investing Articles

1 Stocks and Shares ISA mistake that will make me a better investor in 2026

All investors make mistakes. The best ones learn from them. That’s Stephen Wright’s plan to maximise returns from his Stocks…

Read more »

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

I asked ChatGPT if £20,000 would work harder in an ISA or SIPP in 2026 and it said…

Investors have two tax-efficient ways to build wealth, either in a Stocks and Shares ISA or SIPP. Harvey Jones asked…

Read more »