Belgium’s Circular Letter 2026/C/94 outlines withholding obligations, calculation rules, opt-out procedures, and transitional arrangements under the new 10% capital gains tax on financial assets.
Belgium’s tax administration, FPS Finance, has published Circular Letter 2026/C/94 on 20 October 2026, clarifying withholding tax obligations under the new capital gains tax regime for financial assets, arising from the new capital gains tax on financial assets introduced by the Law of 6 April 2026.
The circular complements Circular Letter 2026/C/74 (published on 22 July 2026), which focuses on the personal income tax treatment of these capital gains.
The key administrative, procedural, and calculation aspects in Circular Letter 2026/C/94 are summarised below:
Scope of withholding at source
Withholding at source applies only to Belgian resident individuals realising capital gains on qualifying financial assets held as part of the normal management of their private assets. Covered assets include financial instruments and certain life insurance and capitalisation contracts.
The rules exclude non-residents and gains involving internal capital gains, substantial shareholdings of at least 20%, crypto-assets, electronic money, investment gold, central bank digital currencies, specified Branch 21 death cover policies, and capital gains triggered by emigration from Belgium.
Withholding base and calculation mechanism
Belgium applies a 10% withholding tax on positive capital gains. Withholding agents do not account for annual exemptions, higher acquisition values, or capital losses, which taxpayers must claim through their annual tax returns. Assets acquired before 2026 are generally valued at their market value on 31 December 2025.
If acquisition costs cannot be verified, tax applies to gross proceeds, subject to later correction through the tax return. FIFO accounting and applicable exchange rates govern calculations. Belgian financial intermediaries and insurers withhold the tax, while beneficiaries receiving payments from foreign insurers report the gains directly.
Opt-out regime and information reporting
Under Article 265/1 WIB 92, taxpayers can opt out of withholding at source per account or per contract. The opt-out must be communicated in writing or electronically at account opening or before the first transaction. Late notice applies from the next taxable period.
For joint accounts, all holders must agree. If one objects, withholding applies to the whole account. For insurance contracts, the opt-out works per beneficiary.
Any single holder or beneficiary can revoke, but only once per taxable period, effective the following period.
With an active opt-out, the financial intermediary files an annual BELCOTAX return (281.08 for accounts, 281.09 for insurance) by 1 March of the next year, listing the taxpayer’s identity, account or contract numbers, and total capital gains. The taxpayer then declares those gains on their own tax return.
Transitional rules for income year 2026
The law applies from 1 January 2026, but withholding at source only starts on 1 June 2026.
For gains realised between 1 January and 31 May 2026, taxpayers could ask their Belgian intermediary to pay an “amount equivalent to withholding tax.” The request deadline was 31 August 2026, and payment is due by 30 November 2026 with return RV 273. Making that request is an irrevocable choice not to use the opt-out regime for all of the 2026 income year.
For withholding on gains granted between 1 June and 31 August 2026, the payment and declaration deadline was pushed to 30 November 2026.
Entities subject to legal entities tax (RPB)
Belgian legal entities under RPB (Art. 220, 3° or 4° WIB 92) are subject to the new 10% capital gains tax on financial assets. Exempt: public-benefit institutions eligible to receive deductible donations (Art. 145^33 WIB 92) and specified public entities.
The entity pays the tax itself via an annual return (form RV 273), with no intermediary withholding. Income is deemed granted on the last day of the taxable period.
Shareholdings of 20% or more and internal capital gains are excluded.
Note on equity-based remuneration
Circular 2026/C/94 covers procedural and withholding tax (RV) rules for standard financial instruments and insurance products. It does not cover employee equity incentives (stock options, bank warrants, free shares, discounted shares). Those fall under personal income tax rules, specifically Circular 2026/C/74, which governs their classification, acquisition timing, and base cost.
Earlier, Belgium’s Ministry of Finance published Circular 2026/C/74 on 22 July 2026, explaining the personal income tax treatment of capital gains on financial assets under the legislation enacted on 6 April 2026. Corporate entities and withholding tax are addressed separately.
