The same ISIN, two different bills
A Belgian investor buying the exact same accumulating world ETF regularly sees it taxed at 1.32% at one broker and 0.12% at another. On a €10,000 order that is the difference between €132 and €12 — an elevenfold gap on an identical trade.
This is a real, documented divergence between brokers such as Bolero and DEGIRO, not a rounding difference and not a mistake by either of them. Both are applying the same rule. They are reading one of its inputs differently.
The rule both brokers are applying
For a fund, the TOB rate turns on two conditions, and the top rate needs both together:
| Registration | Share class | Rate |
|---|---|---|
| Belgium | accumulating | 1.32% |
| Belgium | distributing | 0.12% |
| EEA, not Belgium | either | 0.12% |
| Outside the EEA | either | 0.35% |
The full rate table, the caps, and why registration is not the same thing as where the fund is domiciled are covered in the companion guide, TOB rates: 0.12%, 0.35% or 1.32%, and how an ETF lands on one.
The point that matters here is narrower: only Belgian registration together with an accumulating share class reaches 1.32%. So the whole disagreement between two brokers on one accumulating ETF comes down to a single question — is this share class registered in Belgium or not?
The compartment rule that makes the divergence possible
Most large ETFs are structured as umbrella funds: one legal fund with many compartments, and within a compartment several share classes — typically an accumulating class and a distributing class of the same strategy.
The Belgian administration treats registration as an umbrella-level fact: as soon as one compartment of the fund is registered for public distribution in Belgium, all of its compartments are treated as registered.
That rule is the reason two honest brokers can land on different rates. It opens two defensible readings of the same accumulating class:
- Read registration at the umbrella level. If any sibling compartment or class is registered in Belgium, the accumulating class inherits that registration, is therefore "Belgian registered", and — being accumulating — is taxed at 1.32%.
- Require evidence for the specific class. Treat the accumulating class as Belgian-registered only if that class itself is shown to be registered. Absent that specific evidence, it stays a non-Belgian EEA fund at 0.12%.
Broadly, Bolero's figure follows the first reading and DEGIRO's follows the second. One inherits registration across the umbrella; the other asks to see it for the exact class being traded.
What this means when you self-declare
If your broker withholds TOB, it applies its own reading and you receive whatever it charged. But when TOB is self-declared — the situation for investors on brokers that do not withhold — the rate is not something to copy from whatever a different broker charged on the same ISIN. It has to be determined from the fund's own registration status.
A few practical consequences of the divergence:
- Two brokers charging different TOB on one identical trade is expected, not a sign that one of them is wrong.
- The amount withheld can differ for identical trades placed the same day at two brokers.
- A discrepancy between two brokers on one ISIN is a useful signal: it tells you the registration status of that share class is worth checking directly, rather than assumed.
How to check which reading fits your fund
Registration is published by the FSMA and stated in the fund's KID (key
information document). It cannot be read off the ISIN — an IE (Irish) ISIN says
nothing about whether the fund is registered in Belgium.
Two things are worth looking at:
- whether the umbrella appears in the FSMA register of funds admitted to public distribution in Belgium;
- whether the specific accumulating class you hold is the one registered, or whether it would be inheriting registration from a sibling class.
Those two facts are exactly what the two brokers weigh differently. Knowing them for your own holding is what turns "two brokers disagree" into a rate you can stand behind.
How Belfolio handles it
Belfolio curates registration per instrument rather than guessing it from the ISIN, and reports the rate as unknown for a fund whose registration status has not been established. Between 0.12% and 1.32% there is no safe default: the two candidate answers differ by a factor of eleven, and an acknowledged gap is more honest than a confident wrong number.
Always verify your figures
Belfolio computes and presents these amounts for information only. This is not tax advice. Verify them with the FPS Finance or your accountant before filing.
Published 6 Aug 2026