How much tax do you pay on index funds in the UK?
Connor is a journalist with over 10 years' experience who specialises in finance and business news. Based in London, he also works for Sky News and the BBC.
Last updated 7th April 2026
8 min read
Index funds and ETFs that allow investors to passively track the stock market – or specific parts of the stock market – have surged in popularity across the UK in the past few years.
Recent figures from Hargreaves Lansdown reveal they now represent more than 10% of client investments.
But before we all get too cosy with the passive-investing revolution, there’s a rather large elephant lumbering around the room: tax.
How much HMRC takes from your returns largely depends not on what you invest in, but how you hold it – and the way your gains show up.
In some cases, you won't need to pay any tax at all.
Financial Interest provides guidance, not advice. If you’re unsure about anything, speak with a qualified adviser. When investing, your capital is always at risk. Past performance does not guarantee future results.
Tax-efficient investing
Everyone in the UK can invest up to £20,000 annually in a stocks & shares ISA – and anything you make inside it is completely tax-free. And yes, that includes ETFs and index funds.
Any profits you make don't count towards your £20,000, and you get a fresh allowance when the tax year begins again every April.
If you've got questions about how stocks & shares ISAs work, we're bound to have answered it in this detailed guide.
It's a similar story – but even better – for self-invested personal pensions, more commonly known as SIPPs.
Not only will you not pay tax on any returns from index funds, stocks, or other investments, you'll also get tax relief. That's the government paying tax back to you.
You'll get 20p back for every £1 you put in if you're a basic-rate taxpayer – and if you're on a higher or additional rate, a further 20p or 25p can be claimed online or through a Self Assessment tax return.
Check out our full explainer on how SIPPs work
But if you're not investing inside a tax-efficient account, HMRC will be all over you like a seagull on chips.
There are three main types of tax liability to be aware of: capital gains tax, income tax on dividends, and stamp duty reserve tax.
And on top of that, there are some other small taxes that will apply when investing in index funds.
Let's demystify them all.
Understanding capital gains tax
Capital gains tax (CGT) is quite a money spinner for the government. Official estimates suggest it'll raise £19.7 billion in 2025/26 – that's worth about £690 per household.
As the name suggests, CGT is a tax on any gains you make by selling an investment – the gains of a capital asset.
Let's imagine that you invest £20,000 across several funds – not inside a tax-efficient account, but instead inside a general investment account – and later sell up when the balance is £35,000. CGT would be due on that profit of £15,000.
Up until recently, Brits had a pretty generous tax-free allowance on capital gains, meaning they could earn £12,300 before paying a penny to the taxman. But this was slashed quite dramatically – all the way down to £3,000 in 2024/25.
In our scenario above, after the £3,000 tax limit is taken into account, £12,000 would be subject to CGT.
What you'll pay in CGT depends on which income tax bracket you're in. It's 18% for basic-rate taxpayers, rising to 24% for higher and additional rate taxpayers.
You'll need to declare these gains on a Self Assessment tax return – and it might be worth enlisting the help of an accountant or financial adviser, who can offer advice on how to (legally) reduce this bill.
For example, transferring assets to your spouse or civil partner means you'll collectively have a tax-free allowance of £6,000. And if you've made losses from other investments in the past four years, they can be deducted from more recent realised gains too.
Income tax on dividends
Dividends are essentially your share of a company’s profits, paid out to investors as a little slice of the earnings.
If returns from dividends exceed a certain threshold, it'll be treated as income. That leads to – you guessed it – tax.
Annual dividend allowances have also been lowered substantially of late – from £5,000 back in 2016/17 to just £500 in 2024/25, and remaining at that level for 2026/27.
Any annual earnings beyond this level will be taxed at 10.75% if you're a basic rate taxpayer, 35.75% if you're on a higher rate, and 39.35% at an additional rate.
This can be settled either by contacting HMRC and requesting a tax code change so it's deducted from your salary or pension – or again, by filling out a Self Assessment tax return.
You don't need to inform HMRC if your dividends come in below £500.
Dividends and capital gains tax at a glance: what you pay and when
If all of that was a lot to take in, we've summarised it in the table below:
| Capital gains tax | Dividend tax | |
|---|---|---|
| What is it? | Tax on the profit you make when you sell an investment for more than you bought it | Tax on income you receive from dividends paid out by companies or funds |
| When is it triggered? | When you sell an investment and realise a gain | When dividends received in a tax year exceed your annual dividend allowance |
| Tax-free allowance (2026/27) | £3,000 of gains per tax year | £500 of dividend income per tax year |
| Example | Buy for £20,000 → sell for £35,000 → £15,000 gain. After the £3,000 allowance, £12,000 is taxed | Receive £1,200 in dividends → first £500 tax-free → £700 taxed at your income-tax band rate |
| Tax rates | 18% for basic-rate taxpayers; 24% for higher/additional-rate taxpayers | 10.75% (basic rate), 35.75% (higher rate), 39.35% (additional rate) |
| When you don't pay | If your gains stay below £3,000 for the tax year, or inside a tax-efficient account like an ISA or a SIPP | If your dividends stay below £500 for the tax year, or inside a tax-efficient account like an ISA or a SIPP |
Stamp duty
Buying individual UK shares comes with a surcharge called Stamp Duty Reserve Tax (SDRT). It's 0.5% of your trade, which would be £5 on a £1,000 investment. Your broker pays it automatically, so you don’t even get the satisfaction of saluting as your patriotic donation leaves your account.
As it only applies to individual shares, you won't have to pay it if you're investing in index funds and ETFs.
However, the issuer does pay this tax when purchasing UK shares to include in a portfolio, so it could be passed on to you indirectly in the form of slightly higher management fees.
Smaller taxes to be aware of
Certain other taxes only apply in very specific circumstances.
The PTM levy
A £1.50 charge known as the PTM levy applies if you're selling British shares worth more than £10,000.
This finances the Panel of Takeovers and Mergers, a regulator that aims to ensure the interests of all shareholders are protected if a company is being acquired. However, the PTM levy doesn't apply to index funds or ETFs.
The French Financial Transaction Tax
If you've gained exposure to global index funds consisting of French firms with a market cap of over €1 billion – like Air France, Danone or EDF – fees might end up being a little higher because of the French Financial Transaction Tax. That's because issuers will need to pay a 0.3% charge when adding shares to portfolios.
FINRA and SEC fees
Over in the US, FINRA fees of $0.000166 per share and SEC fees of 0.0008% of a transaction's value also apply whenever index funds are being sold. These are rounded up to the nearest penny, so the minimum you'll pay is $0.01 – and there's a cap for larger transactions of $8.30.
These fees are tiny, and your broker deducts them automatically. Not worth losing sleep over unless you’re already awake worrying about the S&P 500.
Withholding taxes
Finally, withholding taxes may kick in if you're a UK investor who receives dividends from funds that are based abroad. As an example, payouts from a US-based issuer may see 30% deducted from your payouts, falling to 15% if you fill out a W8-BEN form through your chosen trading platform.
Inheritance tax and investments
It’s also worth thinking about what happens to your investments after you’re gone.
Every UK resident gets a £325,000 inheritance tax (IHT) allowance. Above that, the taxman takes 40% of whatever you leave behind – and that includes your investments, index funds very much included.
While ISAs shield you from tax during your lifetime, their contents are fully counted when HMRC totals up your estate. The final valuation is simply whatever your investments were worth at the market close on the day you die.
There are ways to pass investments on more efficiently. You can gift shares, ETFs or index funds to family members, and as long as you survive seven years after making the gift, they fall outside your estate for IHT purposes. Just be aware: gifting can trigger capital gains tax, so professional advice is usually a good idea.
One big exception to this is that if you’re married or in a civil partnership, your spouse can inherit your entire estate – index funds, ISAs, the lot – without paying any inheritance tax at all.
You'll find lots more detail on how stock market investments impact inheritance tax in this full explainer.
Bottom line
Index funds may make investing effortless, but the tax system around them definitely doesn’t. Get the wrapper right and you can keep far more of your returns. Get it wrong, and HMRC becomes your most enthusiastic investing partner.
Financial Interest provides guidance, not advice. If you’re unsure about anything, speak with a qualified adviser. When investing, your capital is always at risk. Past performance does not guarantee future results.
