Belgium's parliament adopts a 10% capital gains tax on financial assets, retroactive to January 2026

Summary

Belgium's Chamber of Representatives adopted legislation on 3 April 2026 introducing a 10% "solidarity contribution" on realised capital gains from financial assets, retroactive to 1 January 2026. The law covers gains from stocks, bonds, investment funds, crypto assets, insurance contracts (branch 21 and 23), and currencies. It uses each asset's December 31, 2025 market value as the cost basis for pre-existing holdings, meaning only appreciation after 2025 is taxable. Each individual taxpayer receives a €10,000 annual exemption (indexed annually); losses can be carried forward at up to €1,000 per year for five years (maximum €15,000 total). Holders of substantial participations, defined as 20% or more of a company's capital, face a different progressive regime: the first €1 million in gains is exempt, with rates ranging from 1.25% (on €1-2.5m) to 10% (above €10m). Belgium had been one of the last EU member states without a general capital gains tax on private investors. The law had been negotiated as part of the Arizona coalition's January 2025 government agreement, approved by the Council of Ministers in July 2025, and reviewed by the Council of State before final adoption.

The split

The De Wever government and Arizona coalition presented the tax as a contribution to fiscal consolidation that, for the first time, brought investment income within Belgium's tax system. The deliberate choice to name it a "solidarity contribution" rather than a "capital gains tax" reflected political sensitivity within the coalition about the optics of taxing capital. Business and investment communities criticised the valuation methodology for unlisted companies and the extension of the tax to assets held through foreign brokers. No formal coalition break emerged over the measure. Opposition on the left argued the 10% rate and the €10,000 exemption were too generous; they had proposed higher rates applied from lower thresholds.

By the numbers

• 10%, solidarity contribution rate on realised capital gains
• €10,000, annual per-person exemption (indexed)
• €1,000/year, maximum annual loss carry-forward (for 5 years; €15,000 total)
• €1 million, exempt threshold for substantial-participation holders (holders of 20%+ of a company)
• 3 April 2026, date Chamber of Representatives adopted the law
• 1 January 2026, retroactive effective date (based on December 31, 2025 cost basis)

Why it matters

The law ends Belgium's status as a Western European holdout without a general capital gains levy, a gap that had long attracted criticism from fiscal economists and the EU as distortive. It also establishes a precedent for how political coalitions can structure such reforms, using a framing shift ("solidarity contribution") and generous exemptions to reduce investor resistance. For the EU, Belgium's adoption may reinforce pressure on the few remaining member states without similar taxes. For investors with Belgian exposure, the retroactive cost-basis rule largely neutralises historical gains, making the practical impact smaller than the headline rate suggests.

What to watch

• Whether the Belgian tax authority clarifies treatment of crypto staking rewards, derivatives, and structured products not explicitly covered in the law.
• Whether the effective yield from the tax meets budget projections, given the extensive exemption architecture.
• Whether Belgium's financial sector sees outflows to jurisdictions without similar taxes.
• Whether the coalition revisits the rate in the 2027 budget cycle.