Pillar Two in Ireland: registration, returns and deadlines

Groups with revenue of €750 million or more pay at least 15% in each country. Who must register with Revenue, what to file, and the 2026 deadlines.

Pillar Two is a global minimum tax agreed through the OECD (Organisation for Economic Co-operation and Development). It was brought into EU law by the Minimum Tax Directive and into Irish law in Part 4A of the Taxes Consolidation Act 1997. It makes sure the profits of large groups are taxed at an effective rate of at least 15% in each jurisdiction where they operate.

Who is in scope

Multinational groups and large domestic groups with consolidated revenue of €750 million or more in at least two of the four previous fiscal years. For Ireland's domestic top-up tax, standalone entities above the threshold are included too. Certain entities, called excluded entities, are outside the rules.

The three taxes

• Domestic top-up tax: collected by Ireland from Irish entities whose effective rate is below 15%, before any other country can. It applies for fiscal years starting on or after 31 December 2023, and Ireland's version has transitional qualified status with the OECD.
• Income Inclusion Rule (IIR) top-up tax: paid by a parent entity on low-taxed profits of group entities abroad. It also applies from fiscal years starting on or after 31 December 2023.
• Undertaxed Profits Rule (UTPR) top-up tax: a backstop where the ultimate parent is in a country without Pillar Two. It generally applies from fiscal years starting on or after 31 December 2024.

Registration

Every in-scope entity in Ireland that falls under any of the three taxes must register through ROS. The deadline is 12 months after the end of its first in-scope fiscal year. For first fiscal years ending in 2024, the deadline was 31 December 2025, later extended to 28 February 2026.

Returns and payment

• the top-up tax return, self-assessment and payment are due within 15 months of the end of the fiscal year. For the first year in scope it is 18 months
• every in-scope entity must also file a Top-up Tax Information Return (TIR) on the same timetable. If the parent or a designated entity files it in another country, the Irish entity files a notification of filer instead
• for groups with a calendar 2024 first year, the first pay, file and TIR deadline was 30 June 2026

Changes in Budget 2027

Following the OECD's Side-by-Side package of January 2026, Budget 2027 amends Ireland's rules to add safe harbours (simpler tests that can mean no top-up tax). They are an extended transitional country-by-country reporting safe harbour and a simplified effective tax rate safe harbour. There is also a substance-based tax incentive safe harbour, an ultimate parent entity safe harbour and the side-by-side safe harbour. It also updates penalty and filing provisions. These take effect when Finance (No. 2) Bill 2026 is enacted.

Work it out

• Corporation tax for your company →

Sources

• Revenue: What are the Pillar Two rules? (15% minimum effective rate for groups with revenue of €750 million or more) (checked 16/10/2026)
• Department of Finance: Budget 2027: Tax Policy Changes (checked 25/10/2026)

General information, not tax advice. HeyPenny is not a tax agent.