📈 FINANCE ACADEMY · NOTION

The ETF, the listed index fund

A basket of assets that trades on the exchange like a share, most often to replicate an index.

Global assets
≈ $20tn
managed by ETFs, end of 2025
In perspective
≈ 17%
of annual world GDP
Level · IntermediateMarketsIndex investingDiversification

An ETF, for exchange-traded fund, is an investment fund listed on a stock exchange. It holds a basket of assets and trades continuously, like an ordinary share. It has become one of the simplest and cheapest ways to invest in a diversified way.

1 What is an ETF?

A fund you buy and sell on the exchange, at any moment of the session.

Definition
A basket of assets, listed like a share
An ETF gathers many assets (equities, bonds, commodities, sometimes cryptocurrencies) into a single wrapper whose units trade on the exchange. Most ETFs are index funds: they aim to faithfully replicate a benchmark index, such as the CAC 40 or the S&P 500. Buying a unit of such an ETF therefore amounts to holding, in a single transaction, a fraction of the entire index.
2 How it works

An arbitrage mechanism keeps the price close to the real value of the basket.

Replicating an index. The ETF holds the same securities as the index, in the same proportions, and so tracks its performance.
Creation and redemption of units. Authorised intermediaries can create or destroy units in exchange for the underlying basket of assets, which adjusts supply to demand.
Arbitrage. If the ETF's price drifts from the value of its basket, these intermediaries step in to profit from the gap, which pulls the price back to fair value.
3 Strengths

Why they won investors over.

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Diversification
A single unit gives access to dozens or hundreds of securities.
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Low fees
Passive management costs far less than an actively managed fund.
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Liquidity
You buy and sell continuously, at the market price.
4 Limits

Diversified does not mean risk-free.

Points of caution
An ETF replicates its index on the way up as on the way down: it offers no protection against a market fall. Some ETFs, known as leveraged, inverse or synthetic, are markedly riskier and unsuited to long holding. Finally, the concentration of an index in a few very large stocks can reduce real diversification.
5 Takeaways

To remember in a few sentences.

An ETF is an exchange-listed fund that holds a basket of assets.
Most replicate an index, at low cost (passive management).
Strengths: instant diversification, low costs, liquidity.
Limits: it follows the market down too; beware leveraged or inverse versions.
This notion illuminates an analysis
The four-year illusion: crypto cycles and institutional ETFs — where the arrival of Bitcoin ETFs reshaped the market's structure.