ETF (exchange-traded fund)

Definition

An exchange-traded fund (ETF) is an investment fund whose shares are listed on one or more stock exchanges and can be bought and sold throughout the trading day like a share. Large institutions called authorised participants create and redeem ETF shares in bulk directly with the fund, which keeps the market price close to the fund's NAV. Most ETFs track an index, though actively managed ETFs exist. In Europe, ETFs are almost always UCITS funds and must carry "UCITS ETF" in their name.

Why it matters

ETFs have made low-cost, transparent index exposure available to everyone, and they publish their full holdings daily, which makes them well suited to look-through analysis. Because a single share class is listed on several exchanges, it has one ISIN but several tickers and trading currencies, which is why fund data should always be keyed by ISIN.

In the API

securityType distinguishes ETFs from traditional funds, structure gives the legal wrapper, and holdings data is available in keyFacts.holdings and topHoldings. Example values:

json
{
  "securityType": "ETF",
  "structure": "UCITS (Irish ICAV)",
  "keyFacts": { "holdings": 1350 },
  "topHoldings": [{ "name": "Example Inc", "weight": 4.8, "isin": "US0000000000" }]
}

The example ISIN inside topHoldings is a placeholder.

Common pitfalls

Exchange-traded commodities (ETCs) and exchange-traded notes (ETNs) trade like ETFs but are debt instruments, not funds, and do not carry UCITS protections. An ETF's market price can deviate from NAV, especially when the underlying market is closed. Physical and synthetic ETFs deliver the same index return by different means; see replication method.