TLDR (too long didn’t read): What you need to know
The Government has announced changes to the way interest earned on cash held within Stocks and Shares ISAs will be treated from 6 April 2027.
From that date, interest earned on cash held within these accounts will be subject to a 22% charge. The change forms part of wider ISA reforms, including a reduction in the amount under-65s can pay into Cash ISAs, from £20,000 to £12,000 a year, while the overall ISA allowance will remain £20,000.
Importantly, the changes apply to interest earned on cash balances, not to investments held within a Stocks and Shares ISA.
The key changes
From 6 April 2027, interest earned on cash held within a Stocks and Shares ISA will be subject to a 22% charge.
The overall ISA allowance will remain at £20,000. However, under the proposed changes, the amount under-65s can save in a Cash ISA each tax year will be capped at £12,000. The remaining allowance can still be used across other ISA types – for example, a saver could put £12,000 into a Cash ISA and £8,000 into a Stocks and Shares ISA.
The tax treatment of qualifying investments held within a Stocks and Shares ISA is unchanged.
Why are these changes being introduced?
ISAs have long been one of the UK’s most popular ways to save and invest, offering tax advantages that encourage people to build wealth over the long term.
The Government says these reforms are intended to encourage more people to invest rather than hold larger cash balances within the ISA system. By reducing the amount that can be paid into a Cash ISA while maintaining the overall ISA allowance, the aim is to direct more money towards long-term investment.
Alongside those changes, the Government has announced that interest earned on cash held within a Stocks and Shares ISA will no longer receive the same tax treatment as it does today.
What does this mean in practice?
Until now, any interest earned on cash held within a Stocks and Shares ISA has generally benefited from the ISA’s tax advantages, even if that money had not yet been invested.
From 6 April 2027, that will change. Interest earned on cash held within a Stocks and Shares ISA will instead be subject to a 22% charge.
The important distinction is that this change applies to cash held within the account, not to investments such as shares, funds or exchange-traded funds (ETFs).
Why does cash build up within a Stocks and Shares ISA?
Cash can build up within a Stocks and Shares ISA for several perfectly normal reasons:
Waiting to reinvest
You may sell an investment before deciding where to invest next, leaving the proceeds as cash for a period of time.
Investing gradually
Many investors choose to invest money over several months rather than investing a large lump sum all at once. This approach can help reduce the impact of short-term market movements.
Receiving dividends
Depending on your investment platform and account settings, dividends may be paid into your ISA’s cash balance before being reinvested.
From April 2027, any interest earned while that cash is sitting in the account will be subject to the new 22% charge.
What isn't changing?
Some of the headlines have understandably caused confusion, but the reforms are narrower than they may first appear.
The Government is not introducing a tax on the investments themselves.
Qualifying investments held within a Stocks and Shares ISA will continue to benefit from the existing ISA tax treatment. The new rules relate specifically to interest earned on cash balances held within the account.
Why has the change attracted debate?
While the Government’s objective is to encourage more long-term investing, the reforms have prompted discussion about how they could affect the way some people manage their investments.
It’s common for investors to hold cash temporarily within a Stocks and Shares ISA. This might happen after selling an investment, while deciding where to invest next, or when gradually investing money over time rather than all at once.
Holding cash for a short period isn’t necessarily about avoiding investment. For many people, it’s simply part of a considered investment strategy.
The new rules mean that any interest earned on those cash balances will now be subject to the 22% charge. For some investors, this may become an additional factor when deciding how and when to invest.
What should investors do now?
Although the changes don’t take effect until 6 April 2027, they are worth understanding now, particularly if you regularly hold cash within a Stocks and Shares ISA.
That doesn’t mean making immediate changes to your investment strategy or tax planning. Decisions about saving and investing should always reflect your wider financial goals, your attitude to risk and your personal circumstances.
As more guidance becomes available before the changes take effect, investors will have a clearer picture of how the new rules will operate in practice.
Our view
These reforms are unlikely to change the role of Stocks and Shares ISAs as one of the UK’s most tax-efficient ways to invest. However, they do change the way cash held within those accounts is treated.
For investors who regularly hold cash while deciding where to invest next, or who prefer to build their portfolio gradually over time, the changes introduce an additional cost that didn’t previously exist.
They also add a layer of complexity to what has historically been a straightforward tax benefit. Until now, interest earned on cash held within a Stocks and Shares ISA has generally been sheltered in the same way as the investments themselves. The proposed changes mean investors will need to be more aware of how cash is held within their ISA, creating additional confusion around a product that has traditionally been valued for its simplicity.
As with many tax changes, the right response will depend on your own circumstances. Rather than reacting to headlines, it’s worth taking the time to understand how the new rules fit into your wider financial plans.
We’ll continue to monitor further guidance and share updates where there are developments that matter to our clients.
ISA Changes FAQs
Will my Stocks and Shares ISA be taxed?
No. The changes relate to interest earned on cash held within a Stocks and Shares ISA, not the investments themselves.
Do I need to move my investments?
Not necessarily. The right approach will depend on your personal circumstances and investment strategy.
When do the new ISA rules start?
The Government has announced that the changes will take effect from 6 April 2027.
Should I stop holding cash in my Stocks and Shares ISA?
Cash can build up for perfectly valid reasons, such as after selling investments or while investing gradually. The changes mean the tax treatment of interest earned on that cash will be different from April 2027, but whether you should change your approach will depend on your individual circumstances.
Need some clarity?
Tax changes can raise plenty of questions, especially when they affect well-established savings and investment products. If you’d like to understand what these ISA changes could mean for you or your business, we’re here to help.
If you’re an existing Harland client and you’d like to discuss the changes or your wider tax planning, get in touch with your dedicated client manager. If you’re new to Harland, book a free discovery call to explore how we can support you.
