Belgium clarifies capital-gains withholding and the 30 November transition

The circular explains the mechanism in Income Tax Code 1992 Articles 261, 265/1, 267 and 269. Withholding is 10% for the specified financial instruments and insurance or capitalisation products. Source withholding generally concerns Belgian-resident individuals; excluded categories and entities subject to legal-entities tax have distinct treatment. A group company’s Belgian presence alone does not establish that it is the withholding debtor.^[1][2]

Intermediaries need transaction and customer facts

A Belgian intermediary involved in a covered transaction is responsible subject to statutory exceptions, including proof of prior withholding and specified intermediary-to-intermediary payments. Belgian insurers account for covered benefits they pay. The withholding base does not deduct the individual’s annual exemption or capital losses. Those adjustments may instead be pursued through the individual return. Without adequate evidence of acquisition value or premiums, withholding can apply to the full proceeds or insurance benefit.^[1][2]

Separate the two transitional cohorts

Ordinary source withholding applies from 1 June 2026. For covered income attributed or paid between 1 June and 31 August, the April law permits payment by 30 November rather than within the ordinary 15 days. Circular paragraph 54 requires the return no later than payment and, in any event, by 30 November. Insurance benefits in this transitional period are deemed opted out unless the customer expressly requests withholding. This is an existing statutory transition explained in October, not a fresh extension.^[1][2]

A separate election covered gains from 1 January to 31 May: all account holders or the insurance beneficiary had to request an equivalent payment by 31 August. A validly requested amount is payable by 30 November, with Form 273 filed before payment under circular paragraph 52. The request excludes opt-out for 2026. Financial groups should verify the relevant customer election and withholding debtor and distinguish these cohorts; the circular does not reopen the August election window.^[1][2]