Stocks and shares ISAs explained

A stocks and shares ISA is a tax-free investment account that lets you put money into a range of different investments, including funds, company shares and bonds¹. The money you pay in is invested on the stock markets rather than held as savings, and any growth and income it produces is free of UK income tax and capital gains tax². You can invest up to £20,000 each tax year, and any dividends and returns on shares and bonds held in the ISA are tax-free³.

The account is a wrapper, not an investment in itself. You choose what goes inside it, either picking your own investments or letting a provider do it for you, and the tax treatment follows whatever the wrapper holds. The trade-off is risk: the value of your investments can fall as well as rise, and you may get back less than you put in⁴. Growth inside the ISA does not use up your allowance, so investments can increase in value within a stocks and shares ISA without eating into the £20,000 you can pay in⁵.

How a stocks and shares ISA works

A stocks and shares ISA is a tax-free investment account that lets you put money into a range of different investments¹. Where a cash ISA holds money as a deposit, a stocks and shares ISA is an account where the money you put in is invested on the stock markets². The provider that runs the account, called the ISA manager, holds the investments on your behalf and administers the tax wrapper.

The wrapper is what does the tax work. ISAs are tax-exempt accounts under which income received in the form of interest, dividends or capital gains is free of UK tax³. That means no capital gains tax when you sell investments at a profit inside the ISA, and no income tax on dividends the investments pay. You do not need to declare ISA income on a tax return.

What you do need to decide is how the account is run. Two broad arrangements exist. With a self-select ISA, you choose each investment yourself, typically through an investment platform, and you decide when to buy and sell. With a ready-made or managed ISA, the provider selects and adjusts a portfolio for you, usually based on a short questionnaire about your goals and attitude to risk. The ready-made and managed stocks and shares ISAs page covers that route in detail.

Two practical points complete the picture. First, investments can grow without using up your allowance: a £10,000 holding that doubles in value has still only consumed £10,000 of the £20,000 you could pay in⁵. Second, the tax shelter is not absolute. A stocks and shares ISA does not shield your investments from inheritance tax, or from stamp duty when buying shares⁹. The ISAs and tax page sets out exactly what is and is not covered.

The £20,000 ISA allowance is shared across all your ISAs

You can invest up to £20,000 per tax year into a stocks and shares ISA, and the same £20,000 is the overall ISA allowance for every adult⁶. It is one allowance per person, not one per account: you can split your £20,000 annual allowance between cash and stocks and shares ISAs¹⁰, so someone who puts £12,000 into a cash ISA has £8,000 left for investing, and vice versa.

The allowance runs with the tax year, from 6 April to 5 April. During the 2026-27 tax year, which runs from 6 April 2026 to 5 April 2027, you can place up to £20,000 into an ISA⁹. Unused allowance does not carry over to the new tax year, and your allowance resets every 6 April⁴, so anything left on 5 April is gone. That makes late March the point at which many investors review what they have used¹¹.

Since 6 April 2024 the rules allow you to open and pay into more than one ISA of the same type in a tax year, so you could hold stocks and shares ISAs with two providers at once, as long as the total across all of them stays within £20,000⁹. The ISA allowance page gives the year-by-year figures, and the end of the tax year page explains the deadline.

Money already inside ISAs from earlier years is separate from this year's allowance. You can hold any amount built up over past years and move it between providers by transfer without it counting towards the current year's £20,000¹². The does unused ISA allowance roll over? page covers this in more depth.

What you can hold in a stocks and shares ISA

The range of qualifying investments is wide, but it has edges. Only authorised or recognised funds may be held in a stocks and shares ISA under current law¹³. For company shares, only shares listed on a recognised stock exchange, or traded on an Alternative Investment Market, can be held in an ISA¹⁴. Shares listed on a foreign stock exchange can also be held, so overseas companies are not excluded¹⁴.

In practice the main categories are:

• Investment funds, including unit trusts and OEICs, which pool your money with other investors
• Company shares listed on recognised exchanges, UK or foreign
• Bonds and gilts, including corporate and government debt
• Securities issued by registered societies, which are qualifying investments for stocks and shares ISA purposes¹⁵
• Fractional shares, which have been allowed in a stocks and shares ISA since the rule change reported in September 2024¹⁶

US shares can be bought and traded in a UK stocks and shares ISA just as you would with UK shares¹⁷. To do so you normally complete a W-8BEN form, which certifies you as a non-US person for tax purposes, and sign the exchange agreements; providers describe getting started as taking around 10 minutes¹⁷.

Two exclusions are worth knowing. Direct holdings of unlisted private company shares generally fall outside the permitted list, because only exchange-listed shares qualify¹⁴. And cash sitting in the account waiting to be invested is treated differently from investments: from April 2027 a tax charge applies to interest on that cash, covered in the rule changes section below. The what investments a stocks and shares ISA can hold page lists the permitted asset types in full.

Fees and charges

A stocks and shares ISA is not free to run, and fees come out of your money whether the investments rise or fall. The main charges fall into a few groups: a platform fee for running the account, fund charges taken inside the funds you hold, dealing costs when you buy or sell, and in some cases an exit fee when you leave.

Exit fees are the charge most easily missed. Most providers charge nothing to transfer out, but others charge exit fees ranging from £15 to £30 per holding¹². On an account holding ten separate investments, that difference between a free transfer and a per-holding charge is substantial, and it is worth checking a provider's transfer-out terms before opening an account rather than after.

The ISA fees and charges page breaks down platform fees, fund charges and dealing costs, and explains how each is calculated. Fees are not capped by the ISA rules, so they vary between providers, and a self-select account where you trade frequently can cost a very different amount from a managed account with one all-in percentage fee.

Is a stocks and shares ISA right for you?

The ISA rules currently provide for three types of ISA for adult savers: a cash ISA, a stocks and shares ISA and an innovative finance ISA¹⁸. Choosing between them is a question of what the money is for and how much falls in value could be tolerated.

The core distinction is what happens to the money. A cash ISA is a savings account: the money you put in cannot go down, and it is not subject to the risks of investing in stocks and shares⁴. A stocks and shares ISA puts the money into investments whose value depends on the market, and there is no guarantee you will get your money back¹. The cash ISA vs stocks and shares ISA comparison sets the two side by side.

A stocks and shares ISA tends to suit money being held for the longer term, where there is time to ride out falls in value, and where the investor is comfortable with the possibility of getting back less than was paid in. A cash ISA tends to suit money that may be needed soon, or that could not afford a fall. Neither is right for everyone, and many people hold both, splitting the £20,000 allowance between them¹⁰.

Two related accounts behave differently. A Lifetime ISA can hold stocks and shares, and comes with a government bonus, but has its own rules on age, property purchase and withdrawal charges¹⁹; the Lifetime ISA explained page covers it. A Help to Buy ISA could not be invested in stocks and shares at all¹⁹. The Lifetime ISA or stocks and shares ISA comparison may help where both are options.

The tax benefits are real but should be weighed honestly. Dividends and returns on shares and bonds held in an ISA are tax-free²⁰, and all interest received on assets held within ISAs is entirely tax free²¹. But outside an ISA everyone also has allowances for dividends and capital gains, so an investor with small gains may see little immediate tax difference, while a larger portfolio benefits much more. The stocks and shares ISA vs general investment account page compares the two.

Transferring an ISA keeps the tax wrapper intact

You can transfer existing cash ISAs and stocks and shares ISAs into a new stocks and shares ISA without affecting your allowance⁹. This is the crucial point: money saved in previous years can be shifted from ISA to ISA, switching provider, without losing the tax breaks²². A transfer is not the same as withdrawing the money and paying it back in, which would use the current year's allowance and, for old subscriptions, could lose the wrapper permanently.

Transfers are not limited by the £20,000 annual ISA limit¹², because transferred money is not a new subscription. The mechanics matter, though: the transfer must be done between providers, with the old ISA manager sending the money or investments to the new one. The how to transfer an ISA page gives the step-by-step process, and the transfer or withdraw and reinvest page explains why the direct route is usually the safe one.

One special case comes from workplace share schemes. Shares taken out of a Share Incentive Plan can be transferred directly into the stocks and shares part of an ISA, as long as this is done within 90 days of leaving the plan, free of capital gains tax; the market value of the shares counts as an ISA subscription²³. The bed and ISA page covers moving existing investments into an ISA by selling and repurchasing.

April 2027: the £12,000 cash limit, new transfer limits and a charge on cash

Three rule changes take effect from 6 April 2027, and each one pushes in the same direction: towards investing rather than holding cash.

The cash ISA limit falls for under-65s. The annual cash ISA subscription limit is being reduced to £12,000 for individuals aged under 65 from 6 April 2027⁸. This introduces a cash limit of £12,000 within the overall annual limit of £20,000²⁴. Anyone wanting to use their full ISA allowance will need to invest at least £8,000 in a stocks and shares ISA²⁵. Savers aged 65 and over are not affected by the reduction and keep the full flexibility⁸. The changes to the cash ISA limit page covers this in full.

Transfers into cash ISAs are restricted. New anti-circumvention rules mean no transfers from stocks and shares and innovative finance ISAs into cash ISAs²⁶. From April 2027, you cannot transfer a stocks and shares ISA into a cash ISA¹². The limits for innovative finance ISAs, Lifetime ISAs and stocks and shares ISAs themselves remain the same²⁷.

A 22% charge on cash held inside a stocks and shares ISA. Cash held in stocks and shares ISAs could be taxed at 22% from April 2027²⁸. The rules introduce a 22% charge on interest paid on cash holdings held in stocks and shares and innovative finance ISAs²⁹. Under the legislation, no relief from tax applies to such interest, and the account manager must pay a flat rate charge to HMRC at the savings basic rate in force for the year; no repayment of tax can be made to the investor³⁰. The charge applies regardless of age, unlike the cash limit.

Your money can fall as well as rise: risks and complaints

The value of your investments can fall as well as rise, and you may get back less than you put in⁴. The success of the investments depends on the market, and as with all investments there is no guarantee of getting your money back¹. This is the defining difference from a cash ISA, where the money put in cannot go down⁴.

Falling values are not in themselves something to complain about, and the Financial Ombudsman Service distinguishes between market losses and complaints about how an account was run. Complaints about stocks and shares ISAs are among the most common investment complaints the ombudsman sees: in 2024-25 the stocks and shares ISA was the most complained-about investment product, with 1,655 new complaints³¹. In the first quarter of 2025-26, 361 stocks and shares ISA complaints were opened and 39% were upheld in the consumer's favour³², and in the first quarter of 2026-27 the number opened was 392³³.

If your complaint is about stocks and shares that you hold in an ISA, the ombudsman directs you to its dedicated consumer page about ISAs³⁴. The usual route applies: complain to the provider first, and if it does not resolve the matter, take it to the ombudsman. The complaining about an ISA provider page gives the process, and the how your ISA is protected page explains what cover exists if a provider fails.

Age, joint accounts and death

Age. You must be at least 18 to subscribe to a stocks and shares ISA: the regulations state that a qualifying individual who is 18 years of age or over may only subscribe to a single stocks and shares account⁷. Under-18s can invest through a Junior ISA instead, and 16 and 17 year olds can apply to open a stocks and shares Junior ISA, with the ISA regulations permitting the management agreement to have effect as though the child were 18³⁵. The Junior ISAs explained page covers the child accounts.

Joint accounts. ISAs are strictly individual. A provider's key features document states it plainly: you cannot open an ISA jointly with any other person³⁶. A couple each open their own ISA, each with their own £20,000 allowance. The can an ISA be held in joint names? page covers this.

Death. When someone dies, their ISA investments form part of their estate, and the ISA does not shield them from inheritance tax⁹. For valuation, ask the ISA fund manager for a valuation and use the closing price on the day the person died¹⁴. A surviving spouse or civil partner may be able to inherit the investments and transfer them into their own ISA, in some cases within 180 days of receiving ownership, and may receive an additional subscription allowance equal to the greater of the ISA value at closure or at the date of death³⁶. The additional permitted subscription page explains the inherited allowance, and the what happens to an ISA when someone dies page covers the process. Note that the usual rule of one stocks and shares ISA per tax year does not stop you opening an ISA solely to receive inherited savings³⁷.