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Physical vs Synthetic ETFs: What’s the Difference?

There are two ways a fund can follow an index. One owns the real shares. The other borrows the result from a bank — and that difference is worth a two-minute read.

Two ways to copy an index

An index is just a list, like "the 500 biggest companies in the US." A fund's job is to follow that list. There are two ways to do it.

The first is physical. The fund takes your money and actually buys the shares on the list. If the list has 500 companies, a Het fonds koopt daadwerkelijk elk aandeel in de index die het volgt (volledige replicatie). More → fund tries to own all 500. You can usually look up its real De individuele beleggingen die het fonds bezit. De grootste enkele worden weergegeven; volledige lijsten worden minder vaak bijgewerkt. More → — the shares it owns.

The second is synthetic. Here the fund doesn't buy every share. Instead it makes a deal with a bank: "pay me whatever this index does." That deal is called a swap. The copying method — physical or synthetic — is called Hoe het fonds zijn index kopieert: door de aandelen rechtstreeks te kopen (fysieke replicatie) of met behulp van een swapcontract (synthetische replicatie). More → .

The swap, and its catch

So why would a fund use a Het fonds maakt gebruik van een swapcontract met een bank om de index na te bootsen, in plaats van de aandelen rechtstreeks aan te houden. More → swap instead of just buying the shares? Sometimes it's cheaper or easier — especially for hard-to-reach markets or for an De gepubliceerde lijst met beleggingen (de "index") die het fonds probeert na te bootsen, zoals de MSCI World. More → with thousands of names. The swap can track the target very closely.

Here's the honest catch: a swap is a promise from a bank. If that bank ran into deep trouble and couldn't pay, the fund could face a problem. That's called counterparty risk — the risk the other party doesn't keep its side.

It's not as scary as it sounds. In Europe, rules cap how much a swap can be "owed," and funds hold a pot of backup assets. But the risk isn't zero, and a physical fund simply doesn't have it.

What this means for you

Neither type is a winner or a loser. They're two roads to the same place, with different bumps.

Physical is the easy one to picture: the fund owns the real things. No swap, no bank promise. The trade-off is it can cost a touch more to run for tricky markets, and a giant index may be expensive to buy share-by-share.

Synthetic can track tightly and reach awkward corners cheaply. The trade-off is that swap promise and the counterparty risk behind it.

The grown-up move isn't picking a "side." It's knowing which one a fund uses — it's written in the fund's fact sheet — and being comfortable with the trade-off before you ever put money in. Now you can read that line and actually know what it means. 🐹

🤔 What's the main difference between a physical and a synthetic ETF?

Common questions

Is synthetic dangerous?
Not dangerous, but it carries one extra risk: counterparty risk. A Het fonds maakt gebruik van een swapcontract met een bank om de index na te bootsen, in plaats van de aandelen rechtstreeks aan te houden. More → fund relies on a bank keeping a promise (the swap). European rules cap how much can be owed and require backup assets, so a single bank's trouble shouldn't sink the fund — but the risk isn't zero, and a physical fund avoids it entirely.
How do I find out which type a fund uses?
Look at the fund's fact sheet or its key information document (KID). It states the Hoe het fonds zijn index kopieert: door de aandelen rechtstreeks te kopen (fysieke replicatie) of met behulp van een swapcontract (synthetische replicatie). More → method: "physical" (or "full"/"sampled") means it owns shares, while "synthetic" or "swap-based" means it uses a swap. This guide just helps you understand the words — it isn't a nudge toward either one.
Does physical mean the fund owns every single share?
Not always. A Het fonds koopt daadwerkelijk elk aandeel in de index die het volgt (volledige replicatie). More → fund tries to own all of them. Some physical funds own a representative sample instead to save costs. Either way, the key point holds: a physical fund holds real shares, while a synthetic one leans on a swap with a bank.