If you are saving for retirement or another goal, you may be wondering whether moving some of your savings into an ISA could make them more tax-efficient, or whether investing through a Stocks and Shares ISA could offer greater long-term growth potential.
Choosing the right type of ISA comes down to what you’re saving for, when you need access to the money, and your risk appetite. Cash ISAs can offer greater certainty and, depending on the account, easier access, while Stocks and Shares ISAs offer more potential for growth over time, but with greater risk.
In this guide, we’ll look at how each option works, the tax benefits, accessibility, risk, and potential returns to help inform your decision.
Redwood Financial is a team of experienced Financial Advisers that has helped clients enjoy, grow, and protect their wealth for decades. We can help you consider your options and provide valuable savings and investment advice.
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What is an ISA (Individual Savings Account)?
An ISA is a savings or investment account where the interest you earn is free from UK Income Tax. Interest and dividends within an ISA are free from UK Income Tax, and investment gains are free from Capital Gains Tax.
There are four main types of adult ISA, as well as Junior ISAs for children under 18:
- Cash ISAs – for savers who want to save cash and earn tax-free interest.
- Stocks and Shares ISAs – for people investing for longer-term growth.
- Lifetime ISAs – for eligible adults saving for a deposit on their first home or for later life.
- Innovative Finance ISAs – for people investing through peer-to-peer lending or similar investments.
- Junior ISA – for parents or guardians saving on behalf of children under 18.
For this article, we will focus on Cash and Stocks and Shares ISAs.
What is the ISA allowance for 2026/27?
The annual ISA allowance is the maximum you can add to ISAs during the tax year. For the 2026/27 tax year, it is £20,000. The tax year runs from 6 April to 5 April, and you lose any unused allowance at the end of the year.
You can use your full allowance in one ISA or spread it across different ISA types.
How is the ISA allowance changing from April 2027?
From 6 April 2027, the Cash ISA allowance for under-65s will fall from £20,000 to £12,000. The overall allowance will remain at £20,000, so you could still put the remaining £8,000 into other ISAs, such as a Stocks and Shares ISA.
For people aged 65 and over, the £20,000 Cash ISA allowance will remain the same. The Stocks and Shares ISA limit itself will remain £20,000, subject to the overall allowance.
The new rules also introduce restrictions designed to prevent people from circumventing the lower Cash ISA limit.
What is a Cash ISA?
A Cash ISA works much like a tax-efficient savings account. Your money stays in cash, rather than being invested, and the interest is free from Income Tax.
Some Cash ISAs offer easy access, allowing you to withdraw money when you need it. Others are fixed-term and restrict access for a set period, and you may face a penalty for withdrawing early. Interest rates and withdrawal terms vary by provider.
What are the advantages and disadvantages of a Cash ISA?
Advantages
- Simple – They work like an ordinary savings account, except the interest is tax-free.
- Tax-free growth – There is no tax due on any interest from your Cash ISA.
- Low risk level – With a Cash ISA, your money is safe from stock market fluctuations.
- FSCS protection – Eligible deposits are normally protected by the Financial Services Compensation Scheme (FSCS) up to £120,000 per person, per UK-authorised firm if the provider fails.
- Generally Straightforward – Cash ISAs are free to open and easy to maintain, whereas a Stocks and Shares ISA may come with management fees and trading costs. Cash ISAs typically have fewer ongoing charges than investment ISAs, but always check account terms and any withdrawal penalties.
- Access to cash – With an Easy-Access (or Instant-Access) Cash ISA, you can withdraw money whenever you need it. That can make it a useful emergency fund, planned spending in the next few years or money you simply cannot afford to see fall in value.
Disadvantages
- Inflation can reduce the value of your savings – your balance may remain stable, but if inflation increases faster than the interest you earn, your money will not stretch as far.
- Lower growth potential – While cash offers certainty, investing may deliver higher returns over time.
- Variable rates can fall – With an easy-access or variable-rate Cash ISA, your provider can reduce the interest rate, so it is worth reviewing regularly to see if your rate is still competitive.
- The best rates restrict access – Fixed-term Cash ISAs often offer more attractive interest rates, but the catch is your money is typically tied up for one to five years, and you may face a penalty for early withdrawal.
- You may already get tax-free interest elsewhere – Basic-rate taxpayers can earn up to £1,000 of savings interest tax-free each year, while higher-rate taxpayers can earn up to £500. If your savings interest stays within your available Personal Savings Allowance, you may currently pay no tax on interest from an ordinary savings account. However, an ISA continues to shelter eligible interest from UK Income Tax regardless of the amount earned.
A Stocks and Shares ISA is an investment account with ISA tax benefits. Income such as interest and dividends received within the ISA is free from UK Income Tax, while gains on investments held within the ISA are free from Capital Gains Tax
The ISA is simply the wrapper; what sits inside can include a range of investments. For most savers, the money is invested across a mix of investments, often through funds rather than by choosing individual company shares. You can usually invest a lump sum, make regular monthly payments or both.
You can choose to manage the investments yourself, use a ready-made portfolio, or have a financial adviser manage them for you. If you have no previous investing experience, or if you are unsure which investments are suitable for you, you may wish to seek advice from a regulated Financial Adviser. It’s also important to review your investment portfolio regularly to ensure it aligns with your goals and agreed level of risk.
Any investment can rise or fall in value. You could get back less than you invest, so the investment choices inside the ISA matter just as much as the wrapper itself.
What you can invest in depends on your provider or investment platform. Typical options include investment funds, investment trusts, exchange-traded funds, individual shares and bonds.
Investment funds and investment trusts
Investment funds pool money from many investors and spread it across a collection of assets. Investment trusts do something similar, but through a company structure. The advantage is instant diversification across a range of investments, without building your portfolio one asset at a time. Along with the risk of investments falling in value, fund charges also reduce your overall return.
Exchange-traded funds (ETFs)
ETFs are investments you buy and sell on the stock exchange. They offer a simple way to gain broad market exposure through one investment, and you can track a market, sector or asset class. However, that does not mean all ETFs are low risk; it depends on what the fund actually invests in.
Shares give you direct ownership in a company. Bonds involve lending money to a company or the government in return for interest and repayment under agreed terms. They come in different types and carry different levels of risk.
Shares are generally associated with greater growth potential and volatility, while bonds can provide income and may behave differently from shares, although their value can also rise or fall.
Advantages
- Tax-free growth – You do not pay UK Income Tax or Capital Gains Tax on returns made within the ISA.
- Greater growth potential than Cash ISAs – Over the long term, your investment can grow more than cash.
- Wide choice of investment options – You can choose to invest in funds, shares, bonds, investment trusts and ETFs.
- Flexible contributions – You can usually invest a lump sum, make regular payments or both.
- Useful for long-term goals – It’s suitable for building funds for future goals, such as retirement.
- You may lose money – Investing carries risk, and returns aren’t guaranteed, so you could get back less than you invest.
- Less suitable for short-term access – You can normally sell your investments and withdraw the proceeds, but this takes time, and you may have to sell when markets have fallen.
- Charges apply – Investment platforms, advice or dealing fees can reduce your returns.
- More complex than cash – Choosing suitable investments requires some knowledge and requires ongoing maintenance, which is why many people choose the services of an investment manager or financial adviser.
The important question is not simply, “should I save or invest?”, it is “what do I need from my money, when do I need it, and how much risk am I comfortable with?”
A Cash ISA might be suitable if…
- you wish to build an emergency fund
- you want to use the money in the next few years
- you can’t afford to lose the money you invest
- you already have an emergency cash fund elsewhere
- your goal is more than five years away
- you don’t foresee needing the money at short notice
- you want the potential for more growth
- you can cope with losses and are comfortable with the risks
| Cash ISA | Stocks and Shares ISA | |
|---|---|---|
| Main purpose | Tax-efficient cash savings | Tax-efficient investing |
| Risk | No stock market risk, although inflation can reduce the value of your savings | Investments can rise or fall, and you may get back less than you invest |
| Potential return | Interest depends on the account and provider | Depends on the investments held and is not guaranteed |
| Inflation risk | Cash can lose purchasing power over time | Investments may outpace inflation over time, but can also lose value |
| Access | Depends on the type – some offer easy access, some restrict withdrawals for a set period of one to five years | Investments usually need to be sold before you can withdraw the proceeds, so access isn’t always immediate. You may also have to sell at a loss depending on market conditions |
| Typical timeframe | Emergency savings and shorter-term goals | Generally longer-term goals |
| Potential charges | Check account terms, withdrawal restrictions or penalties | Platform, fund and dealing charges may apply |
Speak to Redwood about your savings and investments
How much you should keep in cash and how much you should invest is a highly personal decision. Redwood Financial can help review your existing savings and investments in line with your short- and long-term goals, investment timeframe and capacity for loss.
From there, we can advise on the most appropriate way to invest as part of your wider Financial Plan. If you are planning for retirement, we can also consider whether an ISA, pension or a combination of the two is the most tax-efficient approach.
Contact Redwood Financial to arrange your Initial Meeting and review your savings and investment plans.
Frequently asked questions about Cash and Stocks and Shares ISAs
Should I move my money from a Cash ISA to an investment ISA?
If you have significant Cash ISA savings, it is worth reviewing how much you continue to hold in cash and the potential for investment. A Stocks and Shares ISA has the potential for greater long-term growth, so it’s especially worth considering if you are planning for something five years or more down the line, like retirement.
Consider how much cash you need to keep accessible, and how much loss you can cope with if your investments fall. That’s why it’s wise to get professional savings and investment advice before you go ahead.
If you want to move an ISA, ask the new provider to arrange an official ISA transfer. Simply withdrawing the money and reinvesting it yourself could use up part of your annual ISA allowance, depending on whether your ISA is flexible.
There is no set holding period for a Stocks and Shares ISA, but it’s best suited to long-term investing. It makes more sense if your goal is several years away, to give your investments time to recover from short-term market fluctuations. That said, returns are never guaranteed.
The key is to match your investment timeframe to your goal; if you need to access money early, you may end up selling at a loss.
Yes. It is possible to have both a Cash ISA and a Stocks and Shares ISA. You might use the former as your short-term and emergency fund, while your investments work towards another goal, such as retirement. Your ISA allowance is shared across all your ISAs, so money paid into one reduces the allowance available for the others.
You will need an ISA provider to open and administer a new account. Many providers offer an investment platform where you can manage your investments, see how they are performing and manage your contributions.
Different investment platforms offer different investment choices, fund fees, account charges, and service levels, so it is important to choose what is right for you.
Is a Cash ISA worth it?
Whether a Cash ISA is worth it depends on how soon you need access to your cash, how much interest you currently earn on your savings, and your tax bracket.
Basic and higher-rate taxpayers receive a Personal Savings Allowance, which is the amount of interest you can earn on savings before you have to pay tax on it. In 2026/27, the PSA is £1,000 for basic-rate taxpayers, £500 for higher-rate taxpayers, and £0 for additional-rate taxpayers.
So if you are an additional-rate taxpayer, saving in an ISA is more tax-efficient from the start. For basic and higher-rate taxpayers, it becomes more useful once the interest you earn is likely to exceed your PSA.
A Stocks and Shares ISA may be more beneficial if your goals are a way off in the future.
