Thailand's Pillar Two Global Minimum Tax and What It Means for BOI-Promoted Entities

Thailand began applying a 15% global minimum effective tax rate to large multinational enterprise groups on January 1, 2025, under the Emergency Decree on Top-up Tax B.E. 2567 (2024). The change puts Thailand in line with more than 40 other jurisdictions implementing the OECD's Pillar Two framework, and it creates a genuine tension for any foreign investor weighing a Board of Investment (BOI) promoted manufacturing project against Thailand's underlying 20% corporate tax rate: the incentives that make Thailand attractive on paper can now be partially clawed back if they push a company's effective tax rate below the new global floor.

What Pillar Two Actually Requires

Pillar Two is the OECD's answer to decades of multinational groups routing profits through low-tax jurisdictions. Rather than harmonizing statutory tax rates, it guarantees a minimum effective outcome: any large multinational group must pay at least 15% effective tax on its profits in every jurisdiction where it operates, regardless of what incentives, exemptions, or reduced rates that jurisdiction offers on paper. If a group's effective rate in a given country falls below 15%, a top-up tax closes the gap, collected either by that country itself, by the jurisdiction where the parent company sits, or by other group jurisdictions, depending on which of three mechanisms applies.

Thailand adopted all three of these mechanisms simultaneously rather than phasing them in. The Qualified Domestic Minimum Top-up Tax (QDMTT) lets Thailand itself collect any shortfall on profits earned inside Thailand, before any other country gets the chance to. The Qualified Income Inclusion Rule (IIR) allows a parent company's home jurisdiction to collect top-up tax on a low-taxed Thai subsidiary if Thailand hasn't already done so under its QDMTT. The Qualified Undertaxed Profits Rule (UTPR) acts as a backstop, letting other group entities' jurisdictions collect any remaining shortfall if neither the QDMTT nor the IIR captured it. Adopting all three at once means Thailand is not leaving any gap in the top-up mechanism open for a multinational group to plan around; whichever jurisdiction in the chain has authority to collect the difference, one of them will.

The EUR 750 Million Threshold: Who This Actually Catches

The practical scope of Pillar Two is narrower than the framework's name suggests. It applies only to multinational enterprise groups with consolidated global annual revenue above EUR 750 million (roughly USD 800 million at mid-2026 exchange rates) in at least two of the four preceding fiscal years. For the overwhelming majority of foreign investors setting up a Thai entity, whether a mid-sized pharmaceutical distributor, an independent medical device importer, or a founder-led company formation, this threshold simply does not apply. A standalone Thai subsidiary of a group with global revenue under that figure is entirely outside Pillar Two's reach, and its Thai tax position is governed by ordinary corporate tax rules and whatever BOI incentives it separately qualifies for.

The calculation changes entirely, though, if the client's Thai entity is a subsidiary of a genuinely large global group, the kind of scale seen among major multinational pharmaceutical manufacturers, global medical device companies, or large consumer-health conglomerates with a Thailand manufacturing or distribution footprint. For that investor, the EUR 750 million test is not a theoretical concern; it is a live constraint on how much value a Thailand BOI promotion actually delivers, because the group's global tax function will be modeling Pillar Two exposure across every jurisdiction it operates in, Thailand included.

Where BOI Incentives Collide With the 15% Floor

This is the tension that matters most for a foreign investor evaluating Thailand as a manufacturing location. BOI promotion under the Investment Promotion Act offers real, substantial incentives: corporate income tax holidays running several years, reduced rates once the holiday ends, import duty exemptions on machinery and raw materials, and other benefits designed specifically to pull in the kind of capital-intensive manufacturing investment that pharmaceutical and medical device production represents. Historically, a BOI-promoted company could see its effective Thai tax rate fall well below Thailand's 20% headline corporate rate, sometimes to zero during an active tax holiday period.

Under Pillar Two, an effective rate below 15% for an in-scope multinational group no longer simply stays as a saved cost. It becomes a top-up tax liability instead, collected by Thailand itself under the QDMTT if Thailand chooses to exercise that mechanism (which, having adopted QDMTT alongside IIR and UTPR, it clearly intends to), or by the parent jurisdiction under the IIR if Thailand does not. Either way, the group's consolidated tax bill ends up close to the 15% floor regardless of how generous Thailand's BOI incentive was on paper. The incentive doesn't disappear, but a meaningful share of its intended benefit gets redirected from "tax the company doesn't pay" to "tax someone in the group pays anyway, just not necessarily to Thailand."

The BOI's Response and What It Signals

The BOI has been developing a Qualified Refundable Tax Credit (QRTC) mechanism as a direct policy answer to this exact problem. A QRTC is structured to count as government expenditure rather than a tax reduction under the Pillar Two accounting rules, which means it can preserve real investment value for a promoted company without simply feeding straight into the top-up tax calculation the same way a tax holiday does. The mechanism itself, and how Thailand intends to calibrate it against specific promoted activities, is a separate and still-developing story; the point worth flagging here is simply that Thailand's own investment promotion authority is actively working to keep BOI incentives meaningful under the new global minimum tax regime, rather than treating Pillar Two as a problem outside its remit.

What This Means for a DeeMED Client

For a foreign investor who is the Thai subsidiary of a large multinational pharmaceutical, medical device, or consumer-health group, and who is weighing a BOI-promoted manufacturing project in Thailand as part of building out or relocating regulated production, the headline BOI tax holiday can no longer be taken at face value in isolation. The right move is to get the group's own global tax function modeling the actual net benefit: how much of the BOI incentive survives once Pillar Two's 15% floor and Thailand's QDMTT are factored in, and whether a QRTC-style credit structure, once finalized, changes that math. A BOI approval letter and a Thai FDA or DTAM cannabis license are necessary steps toward operating in Thailand, but for a group large enough to be caught by Pillar Two, they are no longer sufficient on their own to answer whether the investment delivers the tax outcome the headline incentive implies.

DeeMED works with foreign investors structuring the Thai entity itself, choosing between BOI promotion, a Foreign Business License, or a joint-venture structure, and coordinating that entity formation with the Thai FDA or DTAM cannabis license the business exists to hold. If a Pillar Two-scale group is evaluating a Thailand manufacturing footprint, getting the entity structure and license pathway right from the start is a core part of DeeMED's business setup services.