Tax regularisation procedure to end on 31 December 2023: what is next?

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On 31 December 2023, Belgium will end the Unique Liberation Declaration quater (ULD quater) procedure, the latest of a series of temporary regularisation procedures in recent years that allow Belgian resident taxpayers who have not declared certain income to regularise their tax situation. As this deadline approaches, questions are being asked about the prospects for taxpayers wishing to regularise their assets after this date.

Situation until 31 December 2023

ULD quater allows taxpayers to voluntarily regularise their tax-barred assets in exchange for payment of a flat-rate tax of 40% on the assets whose lawful origin they are unable to demonstrate by means of written evidence. Income not subject to the statute of limitations is subject to the payment of "normal" tax increased by 25 points (e.g. dividends that were normally taxable at a rate of 30% can be regularised at a rate of 55%).

ULD quater grants immunity from criminal prosecution, particularly for money laundering offences. In this respect, the certificate of regularisation issued at the end of the procedure was the Holy Grail for many Belgian banks, allowing them to accept the repatriation of assets whose legal origin was not perfectly traceable. In fact, these banks were the main instigators of ULD quater, often pushing their clients to obtain the certificates before accepting any "repatriation" of funds from abroad. This even applies to cases where the taxpayer is beyond reproach, but simply cannot provide written proof of the origin of assets, which may be extremely old.

ULD 4 complete declaration required by 31 December 2023

The tax authorities’s FAQs on ULD quater were updated in July 2023 with the clarification that it will not be possible to file a provisional "pro forma" and "materially incomplete" declaration in 2023 with the view of completing it in 2024. Note that reasonably complete declarations that are submitted in 2023 and updated with minor additions in 2024 should be considered admissible.

Caution, however, is called for, particularly since the FAQ provides no information on the situation after 31 December 2023.

What will happen after 31 December?

The 31 December 2023 deadline raises a number of questions concerning the fate of taxpayers who have not regularised their situation by this date.

Spontaneous procedure with the Prosecutor's office

Questioned in July 2023 about the government's intentions, the Belgian Minister of Finance indicated that from 2024, taxpayers wishing to regularise tax-barred assets would have to declare this to the Prosecutor who would initiate an extended transaction procedure. The Minister of Justice would then be responsible for handling the case.

Further clarification on this, however, is necessary, particularly on the question of whether the tax authorities will actually stop processing regularisation requests beginning 2024 and systematically refer taxpayers to the Prosecutor's office.

Some questions remain, particularly since the Prosecutor remains free to decide whether to prosecute or propose a transaction. The legal certainty offered by this solution is undoubtedly open to criticism.

New "permanent approach" from the tax authorities

Legal certainty is even more doubtful given that the government is currently discussing the introduction of a new "permanent administrative approach" to the regularisation of tax-barred assets.  

This "new approach" would allow the tax authorities to tax up to 45% of tax-barred assets that are spontaneously regularised, in exchange, it seems, for immunity from criminal prosecution.

Inspection Spéciale des Impôts / Bijzondere Belastinginspectie

Another option, which existed between ULD ter (a previous procedure) and ULD quater, is the revival of the spontaneous declaration of income to the Inspection Spéciale des Impôts / Bijzondere Belastinginspectie service, at least for income that is not time-barred. This, however, raises questions about the criminal immunity such a procedure might confer, and the possibility of regularising time-barred capital.


In view of the uncertainty surrounding the situation from 2024 onwards, and the fact that the "new approach" being discussed by the government looks to be even more unfavourable than ULD quater, those wishing to regularise their assets, particularly in the case of repatriation, have a short time to submit their complete regularisation declaration and benefit from criminal immunity.

For strategies regarding the end of ULD quater and advice on Belgian tax law, contact your CMS client partner or these local CMS experts: