Three taxes, three separate questions
For a Belgian resident investing through a broker, three levies can arise:
- the TOB, the stock exchange tax, charged per transaction;
- the dividend withholding tax at 30%, charged on dividends received;
- the capital gains tax at 10%, on gains realized from 1 January 2026.
A broker may collect any, all or none of them. "My broker handles the tax" is never a single fact — it is three, and they come apart.
Where each broker stands
| Broker | TOB | Dividend WHT (Belgian) | Capital gains tax |
|---|---|---|---|
| Belgian brokers (Bolero, Keytrade, ING, Belfius Re=Bel, BNP Paribas Fortis, MeDirect, Saxo BE) | withheld at source | withheld, with a Belgian tax certificate | withheld by default from June 2026 |
| Lynx Belgium | withheld at source | withheld | not withheld — opt-out system |
| DEGIRO | withheld (see the caveat below) | not withheld, no Belgian tax certificate | not withheld |
| Interactive Brokers (IBKR) | not withheld | not withheld | not withheld |
| Trade Republic | not withheld | not withheld | not withheld |
The Lynx exception. Lynx Belgium is a Belgian intermediary and withholds TOB like the others, but it has said it will run the opt-out system for the capital gains tax, meaning it does not withhold that 10% at source. Being Belgian does not settle the question — the three taxes come apart per broker, and Lynx is the clearest illustration of it.
The DEGIRO caveat. DEGIRO now withholds TOB, but sources disagree on whether this is automatic or an option the client enables. The safest reading is that the current default has to be confirmed from your own account settings and statements rather than assumed — a statement showing no TOB line settles it either way. On the dividend side there is no ambiguity: DEGIRO withholds no Belgian dividend withholding tax and issues no Belgian tax certificate.
The capital gains tax from June 2026
From June 2026, Belgian intermediaries withhold the 10% capital gains tax by default. A client opt-out existed until 30 June 2026.
Two points follow that are easy to miss.
The scope starts earlier than the withholding. Gains realized from 1 January 2026 are in scope, including gains realized in the window before withholding began. The absence of withholding on a January or February 2026 disposal does not put that disposal outside the tax.
DEGIRO and foreign brokers do not withhold it at all. Clients of DEGIRO, IBKR and Trade Republic settle the capital gains tax annually, through the tax return.
What each combination actually leaves you to do
Only Belgian brokers. TOB and dividend withholding are settled at source, and from June 2026 the capital gains tax is too. What remains is the annual return, because the €10,000 exemption and loss offsets exist only there. Tax withheld at source is computed without knowledge of your exemption or your losses, so it is a provisional payment, not a final settlement.
DEGIRO. TOB is likely handled, subject to the caveat above. Dividends arrive without Belgian withholding and are declared through the annual return — and without a Belgian tax certificate, the figures have to be rebuilt from statements. Realized gains are settled annually as well.
IBKR or Trade Republic. Nothing is withheld. TOB is self-declared monthly through MyMinfin, on its own schedule, entirely separate from the annual return. Dividends and realized gains are settled through the annual return. Which export to pull from Interactive Brokers, and what the import produces, is covered in Interactive Brokers and Belgian taxes.
A mixture, which is the common case. Each broker applies its own logic to what passes through it, and none of them sees the rest. The Belgian broker withholds 10% on its own gains without knowing about losses realized elsewhere. The foreign broker withholds nothing at all. Only the return brings the two together.
The record that ends up being needed
Whatever the mix, the same underlying data has to exist per broker, across the whole holding period rather than the current year alone:
- purchases and sales with date, quantity and price;
- the 31 December 2025 closing value for positions held before 2026;
- tax already withheld, per broker and per type;
- dividends received and the withholding applied to them;
- for TOB self-declaration, transactions grouped by calendar month, since each month is filed separately.
A single-year export is a recurring problem here: it contains disposals whose matching acquisitions live in an earlier file, and a missing acquisition date also removes any chance of demonstrating the ten-year exemption.
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 9 Jul 2026