What is an ETF? Everything you need to know about exchange-traded funds

Exchange-traded funds (ETFs) are a key component of the modern investor’s toolkit. These simple products are gaining in popularity, and can offer a huge range of options for investors.

The European ETF market registered over $56 billion of inflows in January 2026, according to analysis of etfbook.com data by Fidelity International.

“While we continue to move from one geopolitical crisis to the next, the ETF market remains a source of stable growth,” said Neil Davies, Head of ETF product and capital markets, Europe and APAC at Fidelity International.

MoneyWeek

Subscribe to MoneyWeek today and get your first six magazine issues absolutely FREE

Get 6 issues free

Sign up to Money Morning

Don't miss the latest investment and personal finances news, market analysis, plus money-saving tips with our free twice-daily newsletter

Don't miss the latest investment and personal finances news, market analysis, plus money-saving tips with our free twice-daily newsletter

Sign up

As the name suggests, exchange-traded funds or ETFs are funds that are bought and sold on stock exchanges. As such, their prices change in real time like a stock, rather than at the end of each day, and investors can buy them at their current price at any time during stock market opening times.

ETFs come in two forms: active and passive.

Passive ETFs track the performance of a specific sector by investing in a benchmark index. They don’t attempt to beat their benchmark, but to accurately replicate its returns. These are, historically, the most common form of ETF, though active ETFs are increasingly popular.

“The debate around ETFs vs mutual funds has historically been a proxy for the active vs passive debate,” Tom Bailey, Head of ETF Research at HANetf, tells MoneyWeek. This, however, has been changed by the rise of active ETFs.

Active (or actively managed) ETFs have a portfolio manager that adjusts the allocation of securities within the fund to try to beat the performance of the benchmark index (if there is one – some active ETFs aren’t based on an index at all).

According to analysis from research provider Morningstar, the value of assets held in European ETFs increased 49% from €52.5 billion to €78.4 billion over the course of 2025.

Types of ETF

Like any type of fund, there are ETFs for almost any purpose. ETFs (or similar products like ETCs) exist for bonds, commodities and currencies, while some (known as multi-asset ETFs) invest in a mixture of asset classes.

Within equities, ETFs can take various forms. You could, for example, use an ETF to invest in a particular geography or region: like the Franklin FTSE Asia ex-China ex-Japan UCITS ETF (LON:FRQX) which provides exposure to Asian countries besides China and Japan.

Or you could use an ETF to invest thematically; that is, into a particular sector or theme. An example of a sector-focused ETF would be the iShares MSCI Global Semiconductors UCITS ETF (LON:SEMI), which invests in an index of semiconductor and semiconductor equipment manufacturers.

How do ETFs work?

ETFs are priced in line with the total value of all their holdings and cash (‘net asset value’ or NAV).

While, in theory, an ETF’s price could diverge from its NAV if investors buy or sell it more than the sum of its individual holdings, a mechanism exists that keeps its price aligned with the assets it tracks. In simple terms, authorised partners create or remove new ETF units when its price diverges from NAV, quickly correcting any discrepancy.

This is in contrast to other funds such as investment trusts, which have a fixed number of shares from inception and can therefore diverge more widely from their NAV.

Pros and cons of ETFs

There are various reasons why ETFs are so popular among investors. These include:

• Diversification: thematic ETFs offer investors a convenient way for investors to gain exposure to a sector or theme whilst diversifying and rebalancing their investment across multiple securities;
• Tax efficiency: ETFs can be held in a stocks and shares ISA, protecting your investment from the taxman;
• Low costs: ETFs, especially passive ones, tend to have relatively low fees compared to other types of fund;
• Transparency: ETFs publish their holdings daily, while mutual funds and close-ended funds aren’t required to and tend only to publish holdings quarterly.

Furthermore, ETFs are traded on exchanges in real time which offers advantages over mutual funds. It “provides greater flexibility and real-time pricing”, Bailey says, adding that end-of-day pricing for mutual funds and the need for orders to be placed in advance “seems archaic” in an on-demand world.

Investors should, however, consider the potential drawbacks of ETFs:

• Passive ETFs will never outperform their benchmarks over the long term. Active ETFs might outperform their benchmark, but they can also underperform it.
• ETFs are designed to achieve a specific investment objective over the long term. They aren’t suitable for short-term trading, as over shorter time frames their performance can vary from their benchmark.

ETFs and ETCs: what’s the difference?

An exchange-traded commodity (ETC) works very similarly to an ETF, but tracks the price of a specific commodity.

This is subtly different from a commodity-focused ETF, which will generally invest in shares of companies that are directly exposed to a commodity (such as copper miners) in order to reflect its price movements. While they might produce similar returns, the underlying mechanism is different.

In all other respects, however, ETCs are very similar to ETFs. They offer everyday investors access to commodity investing without having to use complex instruments such as futures or options.

How to invest in ETFs

One of the best aspects of ETFs is their convenience. They can be bought and held in a stocks and shares ISA, like a stock, so if you don’t already have one, opening one of these is the best first step towards ETF investing.

Before buying, though, consider the type of ETF you want to buy, and research the various options available. There are usually multiple ETFs available for any given sector or asset class, so compare options from different providers to assess factors such as fees and the ETF’s strategy and holdings before deciding which to invest in.

Examples of ETFs

If you’re new to ETF investing, a good place to start might be with a passive fund that tracks a major index.

Some examples include:

• The Vanguard S&P 500 UCITS ETF (LON:VUSA), which tracks the S&P 500;
• The Invesco FTSE 250 UCITS ETF (LON:S250), which tracks the FTSE 250;
• The iShares NASDAQ 100 UCITS ETF (LON:CNDX), which tracks the Nasdaq 100.

More confident investors might want to add ETFs to their portfolio in order to gain exposure to a specific sector or asset class. Some examples of ETFs that could be used in this way are:

• The WisdomTree Artificial Intelligence UCITS ETF (LON:INTL), a passive fund that tracks the NASDAQ CTA Artificial Intelligence Index;
• The L&G ESG GBP Corporate Bond UCITS ETF (LON:GBPC), which offers exposure to the sterling-dominated investment grade corporate bond market by tracking the J.P. Morgan GCI ESG Investment Grade GBP Custom Maturity Index;
• The Royal Mint Responsibly Sourced Physical Gold ETC (LON:RMAU), which tracks the gold spot price. As this is a physical ETC issued by the Royal Mint, holders can exchange shares of the ETC for responsibly-sourced gold coins or bars stored by the Mint.

Can I buy US ETFs from the UK?

Investors based in the UK might want to use ETFs to track the performance of US companies or indices. US regulations mean that UK-based investors cannot buy US-listed funds, but there is a workaround, however, in the form of the UCITS legislation. UCITS (Undertakings for Collecting Investment in Transferable Securities) is a regulatory framework that allows European investors to buy US-listed funds, as long as they carry the UCITS designation.

To find out more about ETFs, subscribe to MoneyWeek magazine.