You may favour Cash ISAs for their security over their Stocks and Shares counterparts, but by doing so, you could be missing out on significant gains.
For the 2025/26 tax year, you can save or invest up to £20,000 across your ISA accounts. There are several types of ISAs, but the two most widely used are Cash ISAs and Stocks and Shares ISAs.
Like regular savings accounts, Cash ISAs offer guaranteed interest and security, making them great for short-term goals, such as building an emergency fund, though they are less likely to keep pace with inflation.
Stocks and Shares ISAs, by contrast, involve more risk but have historically delivered higher returns, making them better suited for long-term objectives.
A recent government report found that the UK has the lowest level of retail investing among the G7 countries, and a large portion of individual wealth remains in low-interest cash accounts. It estimates that around 29 million adults have their cash in accounts returning around 1% interest.
Because of the UK’s tendency to underinvest and oversave, there has been persistent speculation that the chancellor Rachel Reeves may make changes to ISA allowances in the upcoming Budget to encourage more investing via Stocks and Shares ISAs, though this remains to be seen.
Read on to find out why the government wants more investments into Stocks and Shares ISAs.
Billions held in Cash ISAs could be missing out on strong returns
Millions of savers across the UK could be missing out on market gains by opting to play it safe and keep their money in cash accounts instead of making investments.
According to a Paragon report, UK savers held £417 billion in adult Cash ISAs as of May 2025, up from £378.7 billion in January.
This approach could mean you miss out on market returns. The government report cited earlier notes that, over the past decade, stock market returns have averaged nearly 9%, far outpacing cash savings, which, as noted, often return as little as 1%.
Indeed, research from Money Age found that someone who maxed out a Cash ISA every year since their launch in 1999 could have missed out on over £134,000 compared with investing the same amount in FTSE 100 companies.
So, by keeping billions locked in low-interest cash accounts, many UK savers are prioritising safety at the expense of the higher potential returns that long-term investing can provide.
Cash ISAs are less likely to keep pace with inflation over the long term
While the stability and certainty of Cash ISA returns can be valuable for your short-term needs, over time, inflation may steadily erode the purchasing power of your savings.
According to This is Money, a £10,000 deposit into a cash savings account in 1999, when ISAs were first introduced, would have grown by 90% to just over £19,000, before accounting for inflation.
By comparison, the same £10,000 globally invested in the FTSE All-World Index would have increased by more than 650% to over £75,000.
Once inflation is factored in, the real value of that £19,000 in savings falls to under £5,000, while the investment retains much of its value at roughly £65,000.
This difference shows how cash loses its value to inflation over time, whereas investments not only preserve purchasing power but also create opportunities for long-term real growth.
So, while cash accounts offer guaranteed returns and aren’t exposed to market fluctuations, over long time horizons, investing gives your wealth a much greater chance of growing in real terms.
Cash savings still have an important role in your financial plan
Cash savings can still play an important role in helping you stay financially stable and meet your goals. For example, having easy access to liquid funds can be useful for covering unexpected expenses or emergencies.
Once you’ve built up a sufficient cash safety net – say around six months of your salary – it may be worth considering how the rest of your money could be invested for long-term growth.
As you’ve seen, Stocks and Shares ISAs can provide stronger potential returns over time and come with the additional benefit of being tax-free.
While all investments carry risk and are subject to volatility, a financial planner can help you align your portfolio with your risk tolerance, enabling you to manage fluctuations while staying on track towards your goals.
Get in touch
A financial planner can work with you to create a savings and investment strategy that supports long-term growth while ensuring your short-term needs are protected.
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Email us at hello@vwmwealth.com or call us on 0141 229 4004.
Please note
This article is for general information only and does not constitute advice. The information is aimed at retail clients only.
All information is correct at the time of writing and is subject to change in the future.
Please do not act based on anything you might read in this article. All contents are based on our understanding of HMRC legislation, which is subject to change.
The value of your investments (and any income from them) can go down as well as up and you may not get back the full amount you invested. Past performance is not a reliable indicator of future performance.
