Act No. 316/2025 Coll. introduces in particular:

• Alignment with the OECD Model Rules, meaning that the Czech top-up tax will qualify as a so-called Qualified Domestic Minimum Top-up Tax (QDMTT),
• Extension of the deadline for filing the Czech top-up tax return from the current 10 months after the end of the reporting period to 22 months after the end of the reporting period, and
• Extension of the deadline for filing the Czech top-up tax information return from the current 10 months after the end of the reporting period to 15 months, or 18 months in the case of a group’s transition (initial) period.

Although the amendment formally enters into force on the day following its publication – i.e. 3 September 2025 – it will also apply retroactively to top-up tax obligations for reporting periods beginning on or after 31 December 2023.

For example, if your reporting period is the calendar year, the new rules will already apply to the 2024 tax year. The deadlines for related filings for this transition (initial) period are as follows:

• Top-up tax return (Czech and Global top-up tax): 2 November 2026
• Top-up tax information return (Czech and Global top-up tax): 1 July 2026

Finally, please note that the same amendment also brings into effect changes to the Accounting Act, as we have highlighted in our earlier publications.