An ETF, or exchange-traded fund, is an investment fund whose shares are listed on a stock exchange and bought and sold like a company’s shares. Most track an index. You buy one through a share-dealing account, ISA or self-invested pension at a live market price, and pay the fund’s ongoing charge plus your platform’s dealing costs and the gap between the buying and selling price.
The label covers a wide range of products, from funds holding thousands of shares to complex instruments built on swaps. Knowing which kind you are buying, and how it is taxed in the UK, matters more than the three letters on the screen.
How an ETF works
An ETF has two markets. In the primary market, specialist firms create new ETF shares by delivering cash or securities to the fund, or redeem shares by handing them back, usually in large blocks. In the secondary market, ordinary investors buy and sell existing ETF shares with each other on an exchange through a broker.
Creation and redemption keep the market price close to the fund’s net asset value (NAV), the value of its holdings per share. If the price rises above NAV, these firms can create shares and sell them; if it falls below, they can buy shares and redeem them. The price can still drift from NAV, especially when the underlying market is closed or under stress, so the price you pay is not always the value you get.
Physical or synthetic
- Physical ETFs own the securities in the index, either all of them (full replication) or a representative sample. What you see in the holdings list is what the fund owns.
- Synthetic ETFs hold a basket of assets and enter a swap with one or more banks, which pay the index return in exchange for the basket’s return. They can track some markets more cheaply or closely, but they depend on the swap counterparty. The fund documents should name the counterparties and describe the collateral.
Some physical ETFs lend part of their holdings to other market participants for a fee, which brings a smaller counterparty risk of its own. Check how much of that income the fund keeps.
ETFs, ETCs and ETNs
ETFs belong to a wider family of exchange-traded products (ETPs). They look identical on a trading screen but are built differently.
| Product | Legal form | What backs it | Main extra risk |
|---|---|---|---|
| ETF | Investment fund, often a UCITS | The fund’s holdings, kept separate from the manager’s own assets | Tracking and, if synthetic, swap counterparty |
| ETC (exchange-traded commodity) | Debt security issued by a special-purpose company | Usually a physical commodity such as gold held by a custodian, or commodity futures | Issuer structure, custody and, for futures, the cost of rolling contracts |
| ETN (exchange-traded note) | Debt security of the issuer | The issuer’s promise to pay the index return, sometimes with collateral | Issuer default |
The difference shows up in ISA rules. Cryptoasset exchange traded notes “cannot be held in a stocks and shares ISA” and must go in an innovative finance ISA, unless they were already held in a stocks and shares ISA before 6 April 2026 (GOV.UK). Our explainer on UK crypto rules covers that market, and our guide on how to invest in gold compares gold ETCs with bars and coins.
What UCITS means on an ETF
UCITS is the European rulebook for funds sold to the public, covering diversification, liquidity, borrowing and the safekeeping of assets by an independent depositary. Many ETFs sold in the UK are UCITS funds domiciled in the European Economic Area. When HM Treasury granted EEA funds equivalence under the UK’s overseas funds regime in 2024, it said over 8,000 UCITS authorised in EEA states were marketing to UK clients, and that most UCITS available to UK clients are authorised in the EEA, “primarily in Ireland and Luxembourg” (HM Treasury explanatory memorandum). The label tells you the fund meets those rules. It does not tell you whether the index, the strategy or the price suits you.
Accumulating or distributing
A distributing ETF pays dividends or interest to you on dates set out in its documents. An accumulating ETF reinvests the income inside the fund, so the share price reflects it. In an ISA or pension the choice is about convenience. Outside them, both are taxed on the income: HMRC taxes UK investors in an overseas reporting fund on the income the fund reports each year, including income it did not distribute (HMRC Investment Funds Manual, IFM13100), and taxes accumulation units in UK funds as if the income had been paid out (HMRC Investment Funds Manual, IFM03120). Accumulating does not defer the tax.
Reporting fund status
For a UK investor holding an overseas ETF outside an ISA or pension, reporting fund status is the single most important tax check. If the fund was a reporting fund throughout your holding, a gain on sale is normally a capital gain, taxed in 2026 to 2027 at 18% or 24% above the £3,000 annual exempt amount (GOV.UK; GOV.UK). If it was not, HMRC taxes the gain “as if those gains were income” (HMRC). HMRC publishes a list of reporting funds with each fund’s ISIN, updated every month.
What an ETF costs
- Ongoing charges figure. The fund’s yearly running cost, deducted from the fund.
- Spread. The gap between the price at which you can buy and sell. It is a cost every time you trade.
- Dealing charge. Usually your platform’s share-dealing rate.
- Currency conversion. Many ETFs have several listings in different currencies. Buying a line priced in dollars from a sterling account may add a conversion fee. The listing currency does not change the currency risk of the holdings.
- Platform fee. Charged on the account that holds it.
Stamp duty is not normally one of them for qualifying UK ETFs: transfers of their units are exempt from SDRT and stamp duty under 2014 regulations (HMRC Stamp Taxes on Shares Manual, STSM101065). Firms must give you an estimate of all costs before you invest and an annual statement of actual costs in pounds and as a percentage (FCA Handbook, COBS 6.1ZA.14B).
How to buy an ETF
- Pick the account and wrapper. In the 2026 to 2027 tax year up to £20,000 can go into ISAs (GOV.UK). Use a firm authorised by the FCA, and check its name against the FCA’s Warning List of unauthorised firms.
- Identify the exact product. Search by ISIN, which identifies the fund and share class, and then pick the exchange listing and trading currency.
- Read the documents. The factsheet and disclosure document give the index, replication method, ongoing charge, domicile and whether it distributes or accumulates.
- Check the spread and use a limit order. A limit sets the most you will pay. Spreads can be wider just after the market opens and just before it closes.
- Keep the contract note and annual statements. You need them for tax if the ETF is held outside an ISA or pension.
The Financial Services Compensation Scheme can pay up to £85,000 per person, per firm if an authorised investment firm fails after 1 April 2019, but it does not cover poor investment performance (FSCS). For how an ETF compares with an ordinary fund, see funds or ETFs; for choosing the index, see our guide to index funds for UK investors.
