For people who hold a few funds
You bought some funds. What does the tax office expect now?
Three taxes reach a Belgian portfolio, and for most people only one of them ever needs filing by hand. This page says which is which, in plain language, and links the tool that works out each one.
Whether it reaches you at all
Most of what is said about 2026 concerns a tax on gains that have been realised. A portfolio that simply stays where it is realises nothing.
When it has to be filed
Stock-exchange tax is filed monthly and has a deadline; the annual return comes round once a year. The missed deadline is the expensive part, not the tax.
Who files it — you or the broker
Some brokers withhold the tax and pay it over; others leave the whole filing to their customer. Yours changes what you have to do, not what you owe.
Work out a figure
Each tool takes an amount and gives back the tax with the reasoning that leads to it. No account, nothing to upload.
Read first
The Reynders tax was not abolished: how it stacks with the capital gains tax
The Reynders tax — 30% on the interest component of funds holding more than 10% debt claims — was widely declared dead in 2025, but the law of 6 April 2026 kept it. How the two taxes combine, with a worked example following the circular.
3 Sept 2026
A worked example: a DEGIRO investor with €50,000 in a world ETF, 2024–2026
One fictional investor, one accumulating world ETF, followed from purchase through the 31 December 2025 step-up to a partial sale in 2026 — with the TOB, the step-up value and the 10% capital-gains tax shown line by line.
28 Aug 2026
You are on the opt-out side of the capital-gains tax: what lands on you
Under opt-out nobody withholds the 10% for you. Three jobs move from your broker to you — and one of them cannot be finished yet, because the declaration codes have not been published.
11 Aug 2026
The 31 December 2025 value, and why it usually helps you
For anything bought before 2026, your taxable gain starts from the last closing price of 2025 — not from what you paid.
2 Aug 2026
The ten-year exemption, and why it is measured per parcel
Gains on assets held continuously for at least ten years are exempt — a rule that turns each individual purchase into a record you need to keep.
11 Jun 2026
The €10,000 exemption is never automatic
Every Belgian taxpayer has an annual exemption on realized capital gains — but it exists only on the annual tax return, even when a broker already withheld 10%.
4 Jun 2026
Start with a single order
Type one amount into the stock-exchange tax calculator and the whole mechanism is there: the rate, where the rate comes from, and whether anyone files it for you.
Open the toolsFrequently asked questions
- Does the 2026 capital-gains tax reach me?
- It applies to gains realised on financial assets from 2026 onward. Holding a fund realises nothing; selling one does. The capital-gains simulator walks through a single sale and shows what the rules make of it.
- Do I have to declare anything myself?
- That depends on your broker. Some withhold the tax and pay it over; with others, the filing falls to the customer. The tools say which does which.
- Does the choice of broker change what I owe?
- No. The taxes are set by law and are the same everywhere. What differs is who pays them over, and how much paperwork lands on you.
- What does this cost?
- The simulators and the guides are free and need no account. Nothing you type into them is stored.
Not quite your situation?
The same tools, in the order that suits other ways of investing.