NTS has outlined filing rules, reporting obligations, and deadlines for the Global Minimum Tax regime, including GIR and Top-up Tax Returns, applicable from fiscal years beginning 1 January 2024.
Korea (Rep.)’s National Tax Service (NTS) issued a release on 28 April 2026 setting out Global Minimum Tax filing requirements, including reporting obligations, filing procedures and deadlines for multinational enterprise (MNE) groups.
The global minimum tax is part of the international tax reform aimed at ensuring MNE groups pay an effective minimum tax rate of 15% in every jurisdiction where they operate. South Korea implemented the regime through the “Adjustment of International Taxes Act” in December 2022, effective starting fiscal years beginning on or after 1 January 2024.
Scope and applicability
The rules apply to constituent entities of MNE groups with consolidated annual revenues of at least EUR 750 million in at least two of the four preceding fiscal years. This includes domestic companies and branches of MNE groups, regardless of whether the ultimate parent entity is located in Korea or abroad.
Certain entities are excluded, including government bodies, international organisations, non-profit organisations, pension funds, and specified investment and real estate funds. However, their revenues are still counted when determining whether the EUR 750 million threshold is met.
Top-up tax mechanism
Where the effective tax rate in a jurisdiction falls below 15%, a top-up tax is applied in a set order:
- Qualified Domestic Minimum Top-up Tax (QDMTT): Levied first by the jurisdiction where the low-taxed entity is located.
- Income Inclusion Rule (IIR): Applied where QDMTT does not collect the full top-up tax; for fiscal year 2024, Korea applies this rule.
- Undertaxed Profits Rule (UTPR): Acts as a backstop for remaining unpaid top-up tax, applying in Korea from fiscal years beginning on or after 1 January 2025.
Filing and payment
For the 2024 fiscal year, reporting and payment obligations began on 1 May 2026. For groups with a fiscal year ending 31 December 2024, the deadline is 30 June 2026, or 18 months after the fiscal year-end, whichever is later.
Filings must be submitted through the National Tax Service HomeTax portal. Required submissions include:
- Global Information Return (GIR): Mandatory electronic filing, unless filed by a designated domestic entity or an overseas entity in a jurisdiction with an information-sharing agreement.
- Overseas Constituent Entity Information Return: Required if the GIR is filed by an overseas entity.
- Top-up Tax Return: Required where additional tax is payable.
Penalties and relief
Non-compliance or false reporting may result in penalties of up to KRW 100 million. However, during the transition period (fiscal years 2024–2027), penalties may be waived where taxpayers demonstrate genuine compliance efforts. For fiscal year 2024, non-reporting and under-reporting surcharges are waived, while late payment surcharges are reduced by 50%.
Administrative support
The NTS has introduced supporting measures including a dedicated global minimum tax portal, reporting checklists, and HomeTax data tools using country-by-country reporting information to assist in calculating effective tax rates.
