Should an employer that committed social security fraud still be entitled to social security contribution reductions when regularizing undeclared workers?

Until 30 June 2026, the answer under Belgian social security law could, in certain circumstances, be yes.

An employer who failed to declare workers to the National Social Security Office (NSSO) and was subsequently caught had to regularize the situation. When the social security contributions were recalculated, however, the employer could still benefit from the ordinary social security contribution reductions to which it was legally entitled.

As of 1 July 2026, this has changed. A new specific sanction has been introduced into the Belgian Social Criminal Code: the loss of the benefit of social security contribution reductions.

What does this mean in practice?

Where a court imposes this additional sanction (which remains optional rather than mandatory), the NSSO will no longer apply the contribution reductions to which the employer would otherwise have been entitled when recalculating the contributions due following a regularization.

This represents a significant shift. Under the previous framework, contribution reductions generally had to be taken into account when contributions were recalculated following a regularization. Going forward, courts may deprive employers of those reductions as an additional sanction.

The rationale behind the reform is straightforward: where social security fraud has resulted in a loss of social security contributions for the public authorities, courts now have an additional tool to ensure that employers do not retain an economic advantage through contribution reductions that would otherwise apply.

The introduction of this sanction further strengthens the enforcement toolbox available to the Belgian authorities and increases the financial consequences of non-compliance with social security legislation.