A. Introduction

The Global Minimum Tax, also known as the Global Minimum Corporate Income Tax (GMT), applies to large multinational corporations investing in countries with corporate income tax rates lower than the standard threshold.

The purposes of the Global Minimum Tax are:

• Collect taxes;
• Terminate the race to the bottom in corporate tax rates among countries to attract investment;
• Prevent transfer pricing by multinational corporations.

Therefore, multinational corporations must pay a minimum corporate income tax of 15%, regardless of the geographic location of their headquarters worldwide.

Vietnam promulgated Decree No. 236/NĐ-CP on August 29, 2025, regarding the Global Minimum Tax, which takes effect from October 15, 2025, and applies to the fiscal year 2024 (fiscal year 2024 refers to any fiscal year starting on or after January 1, 2024).

B. Taxpayers

A taxpayer is a constituent entity of a multinational group with annual revenue in the parent company’s consolidated financial statements of at least two out of the four consecutive years preceding the fiscal year in which the tax obligation is determined, equivalent to 750 million EUR or more.

C. Principles of taxation and calculation formula

The Global Minimum Tax applies to two groups of countries: the investing countries group and the recipient countries group. The Vietnamese government has established the following two taxation principles:

1. Taxation principle according to the Qualified Domestic Minimum Top-up Tax (QDMTT): ensures Vietnam collects additional tax on profits generated in Vietnam with a tax rate below 15%.

Tax calculation formula: Qualified Domestic Minimum Top-up CIT = (Top-up tax rate × Top-up taxable profit) + Adjusted top-up tax for the current year (if any).

2. Taxation principle according to the Income Inclusion Rule (IIR): ensures the parent company in Vietnam collects additional tax on subsidiaries abroad with profits taxed below 15%.

Tax calculation formula: Total top-up tax in a country = (Top-up tax rate × Top-up taxable profit) + Adjusted top-up tax for the current year (if any) – Qualified Domestic Minimum Top-up Tax (if any).

D. Who declares and pays the tax

A constituent entity within a multinational group is responsible for declaring and paying taxes in Vietnam. The group must select one constituent entity in Vietnam to notify the tax authorities within 30 days from the end of the fiscal year; if not, the tax authorities have the right to designate one.

The determination of the constituent entity responsible for declaring and paying taxes is stipulated as follows:

• A multinational group has only one entity in Vietnam → that entity submits the tax return and pays the tax.
• A multinational group has more than one entity in Vietnam → the group must provide written notification designating one entity to submit the tax return and pay the tax.

Once determined, the designated entity must register to obtain a tax identification number, then perform the tax declaration and payment.

E. Tax filing deadlines and documentation

• For the Qualified Domestic Minimum Top-up Tax (QDMTT), the latest filing and payment deadline is within 12 months after the end of the fiscal year.
• For the Income Inclusion Rule (IIR), the latest filing and payment deadline is 18 months after the end of the fiscal year for the first applicable year, and 15 months after the end of the fiscal year for subsequent years.

QDMTT tax filing documentation includes:

1. Information declaration form under the Global Minimum Tax Regulation (Form No. 01/TKTT-QDMTT)
2. Supplemental corporate income tax return (Form No. 01/TNDN-QDMTT
3. Explanation note on differences arising from financial accounting standards (Form No. 01/TM)
4. Information declaration form under the Global Minimum Tax Regulation for multinational groups, covering general group information, group structure, and information related to the calculation of effective tax rate and top-up tax of constituent entities in Vietnam, except where the multinational group is not required to file the Global Minimum Tax information declaration in any country (original or copy).
5. Financial data report of each constituent entity used for preparing the consolidated financial statements of the ultimate parent company (original or copy).

IIR tax filing documentation includes

1. Information declaration form under the Global Minimum Tax Regulation (Form No. 01/TKTT-IIR)
2. Supplemental corporate income tax return (Form No. 01/TNDN-IIR)
3. Explanation note on differences arising from financial accounting standards (Form No. 01/TM)
4. Consolidated financial statements of the ultimate parent company (original or copy)
5. Financial data report of each constituent entity used for preparing the consolidated financial statements of the ultimate parent company (original or copy)

F. Recommendations from AS Audit Company

Step 1: Review the parent company, subsidiaries, including intermediate parent companies within the group, to determine if they meet the definition of a “taxpayer,” considering the four most recent fiscal years (2023, 2022, 2021, 2020). If they meet the definition, proceed to the next steps.

Step 2: Nominate the constituent entity responsible for tax declaration and payment, and complete tax identification number registration.

Step 3: Calculate the tax rate and estimate the tax liability.

Step 4: Review regulations on liability reductions during the transition period or initial investment phase in Vietnam.

Step 5: The constituent entity submits the tax filing and pays the tax (if any), while keeping the filing and supporting documents for tax inspection purposes.

AS Auditing Company will continue to provide detailed updates on the application of the Global Minimum Tax in subsequent newsletters.

If further discussion on the above matters is needed, please contact us for consultation.

Compiled by: Võ Phan Sử – Director of AS Audit Company (September 9, 2025)