Belgian Capital Gains Tax 2026: everything you need to know

A historic shift in Belgian taxation

Until end 2025, capital gains on shares held as part of 'normal management of private assets' were completely tax-exempt for individuals. That era is over. From January 1, 2026, a new capital gains tax on financial assets takes effect — a fundamental change in the Belgian tax landscape.

The new law affects everyone holding financial assets: from private investors with a securities portfolio to SME owners planning to sell their company. Understanding the three regimes, exemptions and deadlines is essential.

The three tax regimes

The legislator created three distinct regimes. The standard regime taxes capital gains at a flat 10% rate. This applies to listed shares, bonds, funds, ETFs, derivatives, crypto-assets and certain insurance products (Branch 21/22/23/26/44). An annual exemption of EUR 10,000 per person applies, with EUR 1,000 per year carry-forward for unused exemption (maximum EUR 15,000 after five years).

The second regime — substantial shareholding — applies when the seller holds at least 20% of a company's shares. Progressive rates apply: the first EUR 1,000,000 in gains is exempt per rolling five-year period, then rates climb from 1.25% (between EUR 1M and 2.5M) to a maximum of 10% (above EUR 10M).

The third regime covers internal capital gains: shares sold to a company controlled by the seller. A flat 33% rate applies, designed to discourage tax-driven restructuring via holding companies.

Which assets are covered?

The tax covers: listed and unlisted shares, bonds, funds and ETFs, derivatives, Branch 21/22/23/26/44 insurance products, and crypto-assets. Specifically excluded: pension savings, long-term savings, group insurance, and savings accounts.

For SME owners, the key question is: what is your company worth on December 31, 2025? That value — the reference value — determines the starting point. Only gains above this reference value will be taxed on a future sale.

The December 31, 2025 photo moment

Historical gains — accumulated before December 31, 2025 — are fully exempt. The law creates a 'photo moment': the value of your financial assets on that date forms the starting point. Only value increases after that date are taxable.

Establishing the reference value on December 31, 2025 is therefore crucial. A higher reference value means lower future taxable gains. For unlisted shares — such as shares in your own SME — a formal valuation is required.

Transition period and deadlines

From January 1, 2026, a transition period applies: financial institutions can only withhold the tax at source from the tenth day following the law's entry into force (publication in the Belgian Official Gazette). Until then, taxpayers must self-report their gains via their tax return. However, capital gains are taxable from day one.

For the reference value of unlisted shares, taxpayers have until December 31, 2027 to have a professional valuation performed.

What this means for SME owners

The impact on entrepreneurs planning to sell is significant. The good news for holders of 20% or more: the substantial shareholding regime is relatively favorable. Up to EUR 1,000,000 in gains (per rolling five-year period), no tax is due.

The key to tax optimization? A correct and high reference value on December 31, 2025. That starts with a professional business valuation.