Executive summary

The President signed into law, on 19 June 2026, the Act of 29 May 2026 Amending the Tax Code and Certain Other Acts, which features major developments affecting the rules on reporting tax arrangements, also known as Mandatory Disclosure Rules (MDR). According to the justification provided by the Polish legislature, the primary objective of the updated law is to improve relationships between taxpayers and tax authorities, enhance tax authorities' performance and clarify provisions that have raised some concerns in their application.

The new MDR framework comes into force substantially on 1 October 2026, transitional rules included.

Key developments

Tax-arrangement reporting rules are being significantly amended, likely having a considerable impact on all taxpayers carrying out arrangements that may be reportable. The developments set out in the amendment include the following.

Updated rules on the scope of reportable arrangements and new definitions

Obligations regarding VAT and excise duty arrangements are being repealed.

Arrangements relating solely to Poland (i.e., those that do not meet the cross-border test) will no longer be reportable.

The so-called "other specific hallmarks" (non-DAC6) will be deleted.

The separate role of a facilitator (service provider) will no longer apply, and a facilitator's actions will be captured under the definition of a promoter. As a result, entities earlier classified as facilitators in similar circumstances could qualify as promoters and be required to carry out duties applicable for this role.

The definition of a promoter will be restricted to entities linked with the EU.

Some new definitions are being added (e.g. hallmark, facilitation tasks, participant in an arrangement) and certain existing definitions modified.

Updated duties affecting users and promoters

A user (relevant taxpayer) is required to report a tax arrangement if any of the following is true:

1. No promoter is involved.
2. The promoter has not provided the user with a document confirming the tax arrangement number and/or the relevant information on reporting made (Tax Code (TC) Article 86b Section 2 and Section 3).
3. The promoter who has a legal professional privilege has provided the user with a notification in line with TC Article 86b Section 4a.

An update to the MDR report is required if the information about an arrangement available to the promoter and/or user was not provided in an MDR report filed by another entity.

The rules regarding exemption from the requirement to report a tax arrangement if the arrangement was reported have been updated (Article 86e TC).

Promoters will no longer be required to implement a formal internal MDR procedure referred to in TC Article 86l . Related administrative fines will be repealed.

Following the repeal of the definition of a "facilitator," promoters' duties have been updated. Specifically, a promoter may request that the service acquirer confirm in writing that an arrangement does not qualify as a reportable tax arrangement, and if no such confirmation arrives within seven days, the arrangement is considered to be a reportable tax arrangement.

Rules applicable to professions enjoying a legal professional privilege will be restricted to attorneys, legal counsel, tax advisers, patent attorneys or individuals with a qualifying title obtained abroad.

The time period in which a promoter with a legal professional privilege must provide certain information to the service acquirer is being shortened to seven days (from 30 days).

The number of MDR reports will be reduced. Specifically, the requirement to file the MDR-2 (notification of informing the user) report is being repealed.

The exemption from the requirement to report an arrangement will be extended to standardized arrangements for promoters with a legal professional privilege.

Other selected developments

An option will be available to appoint a proxy to sign the MDR-3 form (notification of scheme application, filed by the user).

The provision on the issuance of general guidance under TC Article 86k will be deleted.

Implications

As a result of the developments, entities should revisit their reporting duties, consider realigning internal procedures and reevaluate the roles of the parties involved in arrangements.

In this context, it will be important for organizations get ready to embrace the new framework in advance. The implementation agenda analyzes not only the updated rules but also how they translate into reporting processes and obligations. Affected entities should contact their tax advisors for assistance in reviewing their MDR duties, realigning reporting procedures and identifying potential risks, as well as in assessing the impact of the new legislation on their operations and implementing necessary realignments.

Importantly, despite earlier announcements, the penalties set out in penal fiscal law, which may exceed 46m Polish Zloty (PLN 46m) in 2026, have not been reduced.

Finally, note that applicable taxpayers should conduct an impact assessment at the earliest possible stage (during the weeks to come), as the amended law is scheduled to take effect on 1 October 2026.