What is a stocks and shares ISA?
A stocks and shares ISA is a tax-efficient investment account that allows you to invest up to £20,000 per tax year in a range of assets including shares, funds, bonds, and investment trusts. All growth and income within the ISA is completely free from income tax and capital gains tax, making it one of the most powerful savings vehicles available to UK residents.
Unlike a cash ISA, where your money earns a fixed or variable interest rate, a stocks and shares ISA exposes your capital to market movements. This means your investments can go down as well as up, but historically, stock market investments have significantly outperformed cash over the long term. Over the past 30 years, UK equities have returned an average of approximately 7–8% per year before inflation.
Anyone aged 18 or over who is a UK resident for tax purposes can open a stocks and shares ISA. You can hold one stocks and shares ISA alongside a cash ISA, a Lifetime ISA, and an innovative finance ISA in the same tax year, sharing the overall £20,000 annual allowance between them.
What can you invest in?
A stocks and shares ISA gives you access to a wide range of investments:
- Investment funds: pooled investments managed by professional fund managers, covering equities, bonds, property, and multi-asset strategies. These are the most popular choice for ISA investors
- Index tracker funds and ETFs: low-cost funds that replicate the performance of a market index like the FTSE 100, S&P 500, or MSCI World
- Individual shares: buy shares in specific companies listed on UK and international stock exchanges
- Investment trusts: closed-ended funds that trade on the stock exchange, often specialising in specific sectors or regions
- Government and corporate bonds: fixed-income investments that pay regular interest and return your capital at maturity
For most investors, a diversified portfolio of low-cost index tracker funds provides broad market exposure at minimal cost. A simple global equity tracker fund can give you exposure to thousands of companies worldwide for an ongoing charge of just 0.1–0.2% per year.
Stocks and shares ISA vs cash ISA
The choice between a stocks and shares ISA and a cash ISA depends primarily on your time horizon and risk tolerance:
- Short term (under 5 years): a cash ISA is usually more appropriate, as there is not enough time to recover from a market downturn. Cash ISAs currently pay 4–5% on fixed-rate products
- Medium term (5–10 years): a stocks and shares ISA is likely to outperform cash over this period, but you need to accept the possibility of short-term losses
- Long term (10+ years): a stocks and shares ISA is almost certainly the better choice. Over any 10-year period in the past century, equities have outperformed cash the vast majority of the time
The impact of this difference compounds dramatically over time. Investing £500 per month for 20 years at 7% average annual return gives you approximately £260,000. The same amount in a cash ISA at 3% produces approximately £164,000 — a difference of nearly £100,000.
💡 You do not have to choose one or the other. Many people use a cash ISA for their emergency fund and short-term savings, and a stocks and shares ISA for long-term goals like retirement, children's education, or a house deposit that is more than five years away.
Charges and costs to watch
The charges on a stocks and shares ISA eat into your returns, so keeping costs low is essential. The main charges include:
- Platform fee: the annual charge for holding the ISA, typically 0.15–0.45% of the fund value or a flat fee of £40–£120 per year
- Fund charges (OCF): the ongoing cost of the investments you hold. Index trackers charge 0.05–0.25%; actively managed funds charge 0.5–1.5%
- Dealing fees: charges for buying and selling, typically £0–£12 per trade. Many platforms offer free dealing on funds
A total annual cost of 0.3–0.5% is achievable using index trackers on a competitive platform. Paying 1.5% or more in total charges can reduce your final pot by 25–35% over 20 years compared to a low-cost approach.
Investment strategies for ISA investors
You do not need to be a stock market expert to invest successfully in an ISA. The most effective strategy for most people is regular investing — contributing a fixed amount each month regardless of market conditions. This approach, known as pound-cost averaging, means you automatically buy more units when prices are low and fewer when prices are high.
A sensible starting portfolio might be a single global equity tracker fund. As your pot grows and your knowledge increases, you can diversify into bonds, property funds, or specific sectors. The key is to start early and stay invested — time in the market beats timing the market.
Review your portfolio once or twice a year to ensure your asset allocation still matches your risk tolerance and goals. Rebalance if necessary, but avoid the temptation to trade frequently, as this increases costs and rarely improves returns.
⚠️ Investments in a stocks and shares ISA can fall in value, and you could get back less than you invested. If you need the money within the next five years, or if any loss of capital would cause serious financial difficulty, a cash ISA or savings account is more appropriate.
ISA transfers and flexibility
You can transfer existing ISAs between providers without losing your tax-free status or affecting your annual allowance. This is useful if you find a platform with lower fees or better investment options. The transfer process typically takes 2–6 weeks.
Most modern ISAs are flexible, meaning you can withdraw money and replace it within the same tax year without using up your annual allowance. Check whether your provider offers this feature before making any withdrawals.
Get expert help with your ISA investments
If you want professional guidance on choosing investments for your stocks and shares ISA, an independent financial adviser can build a portfolio tailored to your goals, risk tolerance, and time horizon. Find a specialist savings and investments adviser through Nesto — matching is free and takes under two minutes.