An open-ended fund and an exchange-traded fund (ETF) can track the same index, hold the same shares and charge similar ongoing fees. The differences that matter in the UK are how you buy them and what that does to price, cost and tax: a fund deals with its manager at a price set after you order, while an ETF trades on a stock exchange at a live price with a spread.
Neither structure is better in itself. Each suits a different way of investing, and the tax details differ in ways that only bite outside an ISA or pension.
Funds vs ETFs: the structures in brief
- OEIC (open-ended investment company). A company whose shares are created and cancelled by the fund as investors buy and sell.
- Unit trust. The older trust-based equivalent. You buy units rather than shares, but the economics are the same.
- ETF. Usually also an open-ended fund, but its shares are listed on a stock exchange. Investors buy and sell them with each other through a broker. Specialist firms create and redeem ETF shares in large blocks with the fund, which keeps the market price close to the value of the holdings.
Investment trusts are a third, closed-ended structure: companies with a fixed number of shares that trade on the stock exchange, often at a premium or discount to the value of their assets. They are a separate subject, and we touch on them only where the comparison helps.
Pricing and dealing
For OEICs and unit trusts, FCA rules say “all deals must be at a forward price” (FCA Handbook, COLL 6.3.9R). Your order is filled at the next valuation point after it arrives, so you never know the exact price in advance. The FCA’s general minimum is two regular valuation points a month (COLL 6.3.4R), and the fund’s prospectus states how often it actually deals.
A fund may use a single price for buying and selling, based on mid-market values, or be dual-priced, with a higher buying price and a lower selling price (COLL 6.3.5R to 6.3.6G). To protect remaining investors from the cost of large flows, the manager may apply a dilution adjustment to the price or charge a dilution levy, and must do so “in a fair manner” (FCA Handbook, COLL 6.3.8R).
An ETF trades continuously while the exchange is open. You see the price before you deal and can use a limit order to cap it. The costs are the bid-offer spread, which can be wider at the open, at the close and when the underlying market is shut, and the chance that the price strays from the fund’s net asset value. For an ETF holding shares in Asia, for example, the London price during the UK afternoon is an estimate of where those shares would trade.
Costs
Both structures publish an ongoing charges figure. On top of that you pay your platform’s account fee and any dealing charge, and the two types are often charged differently: funds may have their own dealing rate, while ETFs usually follow the platform’s share-dealing tariff. Whatever the platform, the FCA requires investment firms to give you an estimate of all costs and charges before you invest and an annual statement of what you actually paid, in pounds and as a percentage (FCA Handbook, COBS 6.1ZA.14B). Compare those totals, not headline fees.
Stamp duty
This is one of the most misunderstood differences.
- OEICs and unit trusts. You do not pay stamp duty or stamp duty reserve tax (SDRT) when you buy OEIC shares or unit trust units directly from the fund manager (GOV.UK).
- UK ETFs. Transfers of units in ETFs that meet the definition in the Stamp Duty and Stamp Duty Reserve Tax (Exchange Traded Funds) (Exemption) Regulations 2014 are exempt from both SDRT and stamp duty (HMRC Stamp Taxes on Shares Manual, STSM101065).
- Overseas ETFs. SDRT applies to existing shares in UK-incorporated companies and in foreign companies with a share register in the UK (GOV.UK); foreign shares bought outside the UK are normally outside it (GOV.UK). Check your contract note: it shows any stamp tax charged.
- Investment trusts. A trust incorporated in the UK is a UK company, so buying its existing shares normally carries the usual 0.5% charge (GOV.UK).
Domicile and reporting fund status
Many funds sold in the UK, ETFs among them, are domiciled elsewhere. When the government recognised European Economic Area funds under the overseas funds regime, HM Treasury said over 8,000 UCITS funds 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, 2024).
Domicile changes your tax outside an ISA or pension. An overseas fund that is a reporting fund reports its income each year, and UK investors are taxed on their share of it whether or not it is paid out; a later disposal is normally taxed as a capital gain.
If the fund is not a reporting fund, UK investors are taxed on gains “as if those gains were income” (HMRC Investment Funds Manual, IFM13100), which can mean income tax rates of up to 45% in England, Wales and Northern Ireland, where Scottish bands and rates differ (GOV.UK) instead of capital gains tax at 18% or 24% (GOV.UK). HMRC publishes a monthly list of reporting funds.
UK-domiciled funds follow a different rule for accumulation units: reinvested income is taxed as if it had been paid out (HMRC Investment Funds Manual, IFM03120).
Side by side
| Feature | OEIC or unit trust | ETF |
|---|---|---|
| Where you buy | From the fund manager, usually through a platform | On a stock exchange, through a broker or platform |
| Price you get | Forward price at the next valuation point, unknown when you order | Live market price, known before you deal |
| Dealing frequency | Set in the prospectus; FCA general minimum two valuation points a month | Throughout exchange trading hours |
| Trading cost | Possible dilution adjustment or levy | Bid-offer spread; price can differ from net asset value |
| Stamp duty or SDRT on purchase | None when bought from the manager | None on qualifying UK ETFs; overseas ETFs depend on registration |
| Typical domicile | UK or overseas | UK or overseas; EEA funds sold here are mainly Irish or Luxembourg |
| Tax check outside a wrapper | Tax vouchers for accumulation units | Reporting fund status if overseas |
| Can sit in a stocks and shares ISA | Yes | Yes |
How the differences play out
An investor paying in a fixed sum every month may care little about intraday prices and more about the dealing charge on each regular purchase, which varies by platform and by structure. An investor moving a lump sum, or switching between holdings on the same day, may value an ETF’s live price and the ability to set a limit. An investor holding outside an ISA or pension should put domicile and reporting status near the top of the list.
Inside a stocks and shares ISA, which can hold “unit trusts and investment funds” (GOV.UK) up to the £20,000 allowance for 2026 to 2027 (GOV.UK), the tax differences fall away and the choice comes down to price certainty and cost. For the index itself, see our guides to index funds for UK investors and global tracker funds; for the mechanics of exchange-traded products, including ETCs and ETNs, see what is an ETF.
