What the Cabinet Approved on 16 June 2026
The Cabinet endorsed two connected instruments under the OECD’s Global Anti-Base Erosion (GloBE) Rules, the framework behind the 15 percent Global Minimum Tax agreed by more than 135 jurisdictions. Together, they give Thailand the legal ability to enforce the top-up tax and to exchange the data needed to calculate it. Domestically, the extended e-tax incentives reward companies that build this digital reporting capability early.
1. Amending Annex A of the Multilateral Convention (MAC)
The Multilateral Convention on Mutual Administrative Assistance in Tax Matters is a treaty jointly developed by the OECD and the Council of Europe, now covering over 140 jurisdictions. Its Annex A lists the taxes each country brings within the treaty. By amending Annex A to include the Qualified Domestic Minimum Top-up Tax (QDMTT) and the Income Inclusion Rule (IIR), Thailand extends its administrative-cooperation treaty to cover the new top-up taxes. As a result, the Revenue Department can request information, run simultaneous examinations, and coordinate enforcement with treaty partners on these specific taxes.
2. Joining the MCAA GIR for GloBE Information Returns
The second measure is participation in the Multilateral Competent Authority Agreement on the Exchange of GloBE Information Returns (MCAA GIR). Under the GloBE Rules, the ultimate parent of a large multinational group must file a GloBE Information Return that reports global income, taxes paid, and effective tax rates by jurisdiction. The MCAA GIR lets tax authorities exchange these returns automatically, without negotiating separate bilateral deals. Consequently, Thailand gains the data infrastructure it needs to assess and collect top-up taxes on in-scope groups.
Why Thailand International Tax Cooperation Matters Now
For years, Thailand served as a regional holding and treasury hub, helped by a broad tax-treaty network and targeted incentive regimes. That model now faces real scrutiny. Because the MCAA GIR reveals where Thai entities sit within a global group and how much tax they actually pay, authorities abroad can quickly spot under-taxed profits.
Moreover, this step confirms Thailand’s direction of travel. The country is a member of the OECD/G20 Inclusive Framework on BEPS and has begun OECD accession talks. Therefore, aggressive structuring that relies on low effective tax rates carries growing risk, while transparent, substance-based operations remain on solid ground.
The Global Minimum Tax Background
The GloBE Rules form Pillar Two of the OECD’s BEPS 2.0 initiative. They set a global floor of a 15 percent effective tax rate for multinational groups with annual consolidated revenue of EUR 750 million or more. A jurisdiction can enforce this floor through three connected mechanisms, summarised below.
| Mechanism | How it works |
|---|---|
| QDMTT — Qualified Domestic Minimum Top-up Tax | Lets Thailand collect top-up tax on locally low-taxed profits first, before other countries can. |
| IIR — Income Inclusion Rule | Requires a Thai parent to pay top-up tax on the low-taxed income of its foreign subsidiaries. |
| UTPR — Undertaxed Profits Rule | Acts as a backstop where neither a QDMTT nor an IIR has already applied. |
Thailand continues to develop domestic legislation to implement these rules. The 16 June 2026 approval supplies the international treaty and exchange framework that this domestic law needs in order to function.
What This Means for Multinationals in Thailand
The practical impact falls on several groups. First, large multinational groups with Thai constituent entities must recognise that Thailand will soon see their GloBE Information Returns filed elsewhere. In addition, once Thailand’s domestic top-up tax is enacted, profits taxed below 15 percent may attract additional tax here.
Crucially, groups that rely on Thai incentives should recalculate their position. Board of Investment tax holidays, regional headquarters benefits, and International Business Center regimes can push statutory rates well below 15 percent. Under the GloBE methodology, however, the effective tax rate is measured differently, so a generous incentive may now trigger a top-up charge elsewhere in the group. Holding and treasury structures routed through Thailand deserve the same fresh review.
Preparing for Thailand International Tax Cooperation
Given the pace of Thailand international tax cooperation, in-scope groups should act now rather than wait for the final domestic law. A practical readiness plan usually covers the following.
- Scope check. Confirm whether the group meets the EUR 750 million revenue threshold and identify every Thai constituent entity.
- Effective tax rate modelling. Recalculate the jurisdictional effective tax rate under GloBE rules, factoring in BOI, RHQ, and other incentives.
- Data readiness. Build the systems needed to produce a GloBE Information Return, since much of that data will be exchanged automatically.
- Structure review. Reassess holding, treasury, and IP arrangements that depend on low Thai effective rates.
- Incentive strategy. Weigh whether existing incentives still add value, or whether a top-up tax elsewhere simply absorbs the benefit.
Because these questions span treaty law, corporate structuring, and tax accounting, most groups benefit from coordinated professional advice. Early planning protects both compliance and commercial value.
Frequently Asked Questions
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Preparing for Thailand’s Global Minimum Tax?
Lex Bangkok advises multinationals, regional headquarters, and international investors on GloBE readiness, effective tax rate modelling, and restructuring under Thailand’s evolving tax-cooperation framework. We turn complex Pillar Two rules into a clear, compliant, and commercially sound plan.
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