Capital gains tax on shares in brief
An overview of Belgium's new tax on realised capital gains on financial assets from 2026, what it covers, and why unlisted shares need special attention.
From 1 January 2026, Belgium taxes realised capital gains on financial assets, including shares, at a flat rate, subject to an annual exemption per taxpayer. Only gains from that date forward are taxable, and shares in unlisted companies require a documented starting value, either from an independent valuation or the statutory formula.
- The tax applies to gains realised on financial assets from 1 January 2026.
- An annual exemption per taxpayer applies before tax is due.
- Unlisted shares need a documented value at 31 December 2025 as a baseline.
What the new measure covers
The measure introduces taxation on realised capital gains on financial assets, which includes shares in companies, whether listed or unlisted. It applies when a gain is actually realised, typically through a sale, rather than on unrealised appreciation held on paper.
The tax took effect from 1 January 2026, and it does not reach back to tax value increases that occurred before that date. This forward-looking design is central to understanding how the measure interacts with shares acquired or built up over many years.
The annual exemption
Each taxpayer benefits from an annual exemption of 10,000 euro, meaning gains up to that threshold in a given year are not subject to the tax. This exemption applies per taxpayer per year, rather than per transaction or per company.
For shareholders with modest or irregular gains, this exemption can mean that no tax is actually due in a given year, even though the measure technically applies to their situation.
Why listed and unlisted shares are treated differently in practice
For listed shares, a market price is observable on any given day, so establishing the value at 31 December 2025 is straightforward. For unlisted shares, no such daily price exists, which is why the framework provides two routes to establish that starting value.
The first route is the statutory formula, equity plus four times EBITDA, applied automatically as a default. The second route is an independent valuation report prepared for the 31 December 2025 reference date, which can replace the formula with a value based on the company's actual circumstances.
Only the increase from the reference date is taxed
Whichever route establishes the starting value, the taxable gain on a later sale is calculated as the difference between the sale price and that starting value, not the full gain since the shares were originally acquired. This is the mechanism that keeps historical value creation outside the scope of the tax.
Why this matters before any sale is planned
Because the starting value depends on choices made now, before any sale is on the table, shareholders in unlisted companies benefit from understanding early which of the two routes, the formula or an independent valuation, better reflects their company's actual position.
Questions on this
Does the tax apply to gains realised before 2026
No. The tax applies to gains realised from 1 January 2026 onward. Sales completed before that date are not covered by this measure.
Is the annual exemption available to every taxpayer
The exemption of 10,000 euro applies per taxpayer per year, meaning each individual taxpayer can offset gains up to that amount before any tax becomes due.
What determines whether the formula or a valuation report is used
The formula applies automatically by default. A shareholder can replace it for the 31 December 2025 reference date by obtaining an independent valuation report before the applicable deadline.
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This information is general. It does not take your specific situation into account and is not tax advice.