ETF vs Mutual Fund: Structure, Trading, Costs and Tax

An exchange-traded fund and a mutual fund can hold exactly the same portfolio and still behave differently. The difference is not what they own but how you get in and out: one trades on a stock exchange like a share, the other deals directly with the fund at a price set once a day.

Same idea, different plumbing

Both are pooled funds: a manager or index rulebook decides what to hold, and each investor owns a proportional slice. Both can be active or index-tracking. Both publish a net asset value (NAV): the value of everything the fund holds, minus liabilities, divided by the number of units or shares.

The difference is the route:

• A mutual fund (in the UK often an OEIC or unit trust; in the EU an open-ended fund or SICAV) issues and cancels units directly. You send money, the fund creates new units at that day's NAV; you sell, it cancels them and pays you.
• An ETF is listed on an exchange. You buy shares from another investor through a broker, at whatever price the market quotes. Behind the scenes, large institutions called authorised participants create or redeem ETF shares in bulk with the fund, which keeps the market price close to the NAV.

Trading and pricing

Mutual funds use forward pricing: an order placed at 11am is filled at the price calculated after the day's dealing cut-off, which you do not know when you place it. Everyone dealing that day gets the same price. You cannot set a limit, and you cannot trade intraday — which, for a long-term investor, is rarely a loss.

ETFs trade continuously while the exchange is open. You see a live price and can use limit orders. In exchange, you meet market mechanics:

1. The bid-ask spread — the gap between the buying and selling price. For large, liquid ETFs it is usually very small; for niche ones or outside the underlying market's hours it can widen noticeably.
2. Premiums and discounts — in stressed markets an ETF's price can drift away from its NAV for a while, because the arbitrage that normally holds them together slows down.
3. Whole-share trading — some platforms only allow whole ETF shares, though fractional trading has become more common.

A worked example of costs in practice

The ongoing charge — the annual fee taken from the fund — is similar in structure for both and is covered in detail in investment fees explained. The difference is in the dealing costs layered on top, and these depend on how you invest. Take an illustrative investor putting in €200 a month:

• Via a mutual fund on a platform with no dealing charge for funds: the €200 buys €200 of units at NAV. Dealing cost: nil (the platform may charge a holding fee instead).
• Via an ETF on a platform charging €5 per trade: each €200 purchase costs €5 in commission, plus a spread of, say, 0.1% (€0.20). That is about 2.6% of every contribution — far more than any plausible difference in annual fund charges.
• The same ETF bought once a year as a €2,400 lump: €5 commission plus €2.40 spread, about 0.3%.

The figures are illustrative; actual platform charges vary widely and many platforms now offer free regular ETF investing. The cheaper wrapper depends on your platform's fee structure and how often you buy, not on the label.

Tax and regulatory wrappers by region

Structure interacts with tax, and this is where regional differences matter most.

United States. ETFs are often more tax-efficient than mutual funds in taxable accounts. Because redemptions are usually handled "in kind" — the fund hands securities to the authorised participant rather than selling them — ETFs tend to distribute fewer capital gains. A mutual fund that must sell holdings to meet redemptions can pass taxable gains to investors who did not sell anything. Inside an IRA or 401(k) the distinction largely disappears.

European Union. Most funds sold to retail investors are UCITS — a common regulatory framework covering diversification limits, liquidity, custody and disclosure, which allows a fund authorised in one member state to be marketed across the EU. Both ETFs and mutual funds can be UCITS. EU rules also require a standardised key information document that sets out costs and a risk indicator. Taxation is national, and some countries treat funds domiciled abroad differently, so domicile and share class (accumulating or distributing) can matter.

United Kingdom. UK investors largely use UCITS-style funds and ETFs, often inside an ISA or pension where income and gains are sheltered. Outside those wrappers, offshore funds held by UK residents need "reporting fund" status to avoid less favourable tax treatment on gains — something to check in the fund's documents rather than assume.

Note also that US-domiciled ETFs are generally unavailable to EU retail investors, as they lack the EU-format disclosure document. Allowances and rules in all three regions change, so the tax authority's website is the place to confirm current treatment.

Choosing between structures, mechanically

Neither structure is better in general. The questions that decide which fits a given situation are practical:

• How does your platform charge for each — per trade, per holding, or a percentage?
• Will you invest small regular sums or occasional lumps?
• Is the account taxable or sheltered, and in which country?
• Does the specific fund you are considering exist in both forms, and with what ongoing charge?
• Do you value a guaranteed end-of-day price or the ability to trade during the day?

Once those are answered, the comparison is usually clear, and smaller than the marketing suggests. For how a fund fits within a wider portfolio, see diversification basics. If tax treatment across borders is involved, a regulated adviser or tax professional familiar with your country is worth consulting.