Think your money is safe in a cash ISA? Read this now

Putting your money in a cash ISA could be a huge mistake. Rupert Hargreaves looks at just why.

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.

Cash ISAs are extremely popular with savers. It is easy to see why. You can save up to £20,000 a year in one and you never pay tax on the interest received. 

This is particularly attractive for higher-rate taxpayers who have to pay tax on any interest income above £500 a year.

What’s more, compared to a stocks and shares ISA, cash ISAs can seem relatively risk-free. But that’s not really the case. In fact, holding your savings in cash could be riskier than investing over the long run. 

Risk/reward

Over the past 10 years, cash as an asset has produced a return of less than zero, after accounting for inflation

According to data from the Financial Conduct Authority, around £635.7bn of British savers’ money is languishing in easy-access savings accounts, not earning more than 0% per year in interest. More than one-third of these accounts have been inactive for more than five years.

Cash ISAs, in particular, have developed a poor reputation for returns. According to analysis by Moneyfacts, 2017 was the worst ever year for cash ISA returns, with the average instant access account offering just 0.93%. On a full ISA allowance, this is equal to £186 a year in interest, which means that tax benefit does not get a chance to kick in.

And even if cash ISAs do protect you from the taxman, they don’t protect you from inflation.

The damaging impact of inflation 

In 2017 the Consumer Price Index — the most widely used measure of inflation in the UK — averaged 2.6%. On this basis, the real interest rate — after deducting inflation — on an average cash ISA was -1.67% for the year. In other words, after adjusting for inflation, your hard-earned money would have lost value.

This is the primary reason why cash ISAs are not a sensible place to store your savings.

Over the past 10 years, low-interest rates have been extremely damaging to savers’ funds. The cost of goods and services has increased by 30.9% since 2008 meaning that your savings would have had to have been growing at a rate of 2.9% a year to keep pace with inflation.

According to my research, not a single provider has offered a cash ISA with this level of interest.

Shares are the way to go 

In general, cash is perceived to be a safer asset than stocks and shares. And to a certain extent, this is true. However, for long-term savers, the evidence is clear, shares are the best way to go.

Cash stored in savings accounts or cash ISAs has lost purchasing power over the past decade. On the other hand, over the same period, the FTSE 100 has returned 7% annualised. That’s 4.1% after inflation. The Footsie 250 meanwhile has returned 8.1% after inflation.

It is difficult to argue with this evidence. Even though cash is perceived as being safer, the combination of low-interest rates and high inflation make for a toxic mix. 

If you want to protect and grow your money, over the long term, investing in the stock market is a much better alternative.

Rupert Hargreaves owns no 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

Finger clicking a button marked 'Buy' on a keyboard
Investing Articles

Stock market correction: Is there still time to buy UK shares cheap?

Long-term investors can do well to stay calm through stock market corrections, and even crashes, and pick up shares when…

Read more »

Warm summer evening outside waterfront pubs and restaurants at the popular seaside resort town of Weymouth, Dorset.
Investing Articles

2 FTSE 100 blue-chips to consider for a new £20k Stocks and Shares ISA

Ben McPoland highlights a pair of high-quality FTSE 100 stocks that have strong momentum on their side yet are trading…

Read more »

Young Caucasian woman with pink her studying from her laptop screen
Investing Articles

Are depressed Lloyds shares just too tempting to miss now?

Lloyds shares are coming under renewed pressure as conflict in the Middle East threatens the fragile global economic recovery.

Read more »

Female student sitting at the steps and using laptop
Investing Articles

7 FTSE 100 shares that look cheap after the 2026 stock market correction

Falling stock markets often present bargain opportunities. Let's take a look at some of the cheapest FTSE 100 shares at…

Read more »

piggy bank, searching with binoculars
US Stock

Up 59% this year, this S&P 500 stock is smashing the index!

Jon Smith points out a stock from the S&P 500 that's flying right now as part of a transformation plan,…

Read more »

Businessman hand stacking money coins with virtual percentage icons
Investing Articles

Stock market correction: a rare second income opportunity?

Falling share prices are pushing dividend yields higher. That makes it a good time for investors looking for chances to…

Read more »

Finger clicking a button marked 'Buy' on a keyboard
Dividend Shares

I just discovered this REIT with a juicy 9% dividend yield

Jon Smith points out a REIT that just came on his radar due to the high yield, but comes with…

Read more »

Aviva logo on glass meeting room door
Investing Articles

£5,000 invested in Aviva shares 5 years ago is now worth…

Aviva shares have vastly outperformed the FTSE 100 over the last 5 years. Zaven Boyrazian explores just how much money…

Read more »