In February 2025, the Enlarged Chamber of the Supreme Administrative Court commented on one of the most fundamental procedural issues of tax law – the nature of the tax assessment deadline. The decision is of fundamental importance for all taxpayers who face tax audits conducted on the edge of legal deadlines.

The judgment brings a significant strengthening of legal certainty and at the same time changes the current practice of the tax administration, which in some cases tried to assess additional tax even after the expiry of the limitation period.

Background to the dispute

According to Section 148 of Act No. 280/2009 Coll., the Tax Code, the tax can only be determined within a period of three years and may be extended depending on the procedural acts of the tax administrator. In the past, however, there has been an interpretation according to which it was possible to assess the tax even after the expiry of this period in the case of a serious breach of obligations or circumvention of the law.

This approach has long been criticized as contrary to the principle of legal certainty and the protection of the legitimate expectations of taxpayers.

Conclusions of the Enlarged Chamber of the SAC

The Enlarged Chamber of the SAC in the case No. 1 Afs 231/2022 unequivocally concluded that:

• the time limit for tax assessment is preclusive, not merely ordinary,

• after its expiry, the tax cannot be determined or assessed additionally,

• There are no exceptions that would allow the time limit to be broken by reference to the purpose of the law or to combat abuse of law.

The court emphasized that a contrary interpretation would lead to an unacceptable weakening of legal certainty and to a de facto denial of the meaning of the statutory time limit.

Practical impacts for taxpayers

The decision has a direct impact on ongoing and future tax proceedings:

• taxpayers can effectively object to the limitation of the time limit,

• the tax administrator must carefully monitor the running of deadlines and procedural steps,

• In the event of a delayed additional assessment, the tax proceedings are illegal.

Procedural defences based on the control of time limits and the correct evaluation of interrupting and prolonging acts are gaining increased importance.

Recommendations for practice

Taxpayers can be recommended to:

• systematically monitor the running of deadlines for all tax proceedings,

• archive decisions and actions of the tax administrator that may affect the running of the time limit,

• in the event of a dispute, actively oppose the prescription and rely on the decision of the Extended Chamber.

Conclusion

The decision of the Enlarged Chamber of the SAC of February 2025 represents one of the most important case law of recent years in the field of tax procedure. It strengthens the legal certainty of companies and at the same time places higher demands on the procedural discipline of the financial administration.