Capital gains tax: Tax authorities issue guidance

On 22 July 2026, the Belgian tax authorities published Circular Letter 2026/C/74 (Dutch | French), providing detailed guidance on Belgium’s new capital gains tax regime, applicable as from 1 January 2026. The circular letter is over 100 pages in length and includes multiple references to the preparatory works as well as clarifying examples related to interpretations by the tax authorities.

For a general overview of Belgium’s capital gains tax regime, please see our Tax Alert dated 3 April 2026 and our more detailed analysis on the Tax Reforms Hub.

This alert summarises the most important points for human resources and reward practitioners.

Summary

General regime

A flat tax rate of 10% applies to capital gains on financial assets—including listed shares, bonds, investment funds, crypto assets, investment gold, and certain life insurance products.

• For share-based remuneration, such as stock option plans, free shares, or shares purchased at a discount, the circular letter confirms the positions taken in the preparatory works. Please see our Tax Alerts dated 15 April 2026 and 6 August 2025.

• For share-based remuneration, employers may wish to inform beneficiaries of the capital gains tax implications (via information sessions or brochures), the impact on arrival in or departure from Belgium and, if there are multiple plans or grants, the computation of the gains (especially if the share transactions are spread over time).

• Multiple examples are provided to clarify the applicable rules, including:
  • The calculation of the taxable base (exemption of historical capital gains, deduction of capital losses, combination of exchange rates when shares are acquired and sold, “first in first out” method, etc.); and
  • The computation of the (complementary) annual exemption and how the prorating should apply in the case of arrival in or departure from Belgium during the year. It is explicitly provided that an optimal use of the annual exemption is not considered as tax abuse.
• It has been confirmed that nonresidents are excluded from the scope of the new capital gains tax. Any capital gains related to shares in Belgian companies that arise from speculation or the atypical management of private assets are no longer in scope for nonresident taxpayers.

• The circular letter also details the interpretation and application of the temporary exemption for capital gains further to restructuring and contribution of shares.

• The costs or taxes related to the acquisition of the shares (e.g., the stock exchange transaction tax or the cost linked to a share valuation report) cannot be deducted from the taxable base.

• Additional practical points on the exit tax are provided, and annex II of the circular letter lists the jurisdictions outside the EU and European Economic Area to which the automatic deferral also applies. The list is relatively limited, and countries such as the UK and the US are not included. For the US, although the Belgium-US bilateral tax treaty contains provisions regarding mutual collection assistance, the tax authorities consider the scope of this provision too limited, which means that no automatic deferral will apply. A specific request for a payment deferral must be filed with the tax authorities and sufficient security for payment of the tax must be provided (e.g., a bank guarantee, a deposit with the Deposit and Consignment Office, the pledge of a financial instrument).

• Taxpayers who left Belgium before the entry into force of the law (i.e., prior to 1 May 2026) do not fall within the scope of the new capital gains tax if they also relinquished their Belgian tax residency status before that date. However, we note that taxpayers who left Belgium on or after 1 May 2026 will also not be able to declare the capital gains or apply the exemption or capital losses as the “special tax return” does not include this new tax regime.

• For pension purposes, the circular letter confirms that second- and third pillar pensions are exempt from capital gains tax; however, the tax may still apply to certain (foreign) life insurance contracts.

Substantial participation gains

Substantial participation gains are taxed at progressive tax rates from 1.25% through 10% and apply where the taxpayer holds at least 20% of the shares of the company at the point of transfer.

• The 20% threshold is assessed per individual taxpayer, on each transfer separately (family holdings are not aggregated) regardless of the type of shares. Profit certificates, stock options, and warrant plans are excluded from the 20% calculation base.

• A EUR 1 million exemption operates as a five-year rolling allowance (“backpack”) to be prorated in cases of partial tax residency.

Internal capital gains

Taxed at a flat tax rate of 33%, internal capital gains arise where shares or profit certificates are transferred to a company directly or indirectly controlled by the taxpayer, alone or together with close family members, at the point of the transfer.

Pending items

A separate circular specifically addressing the 10% withholding tax mechanism has been announced but has yet to be published. The royal decree that contains the exit tax form is also awaited.