Pillar Two and the Hong Kong minimum top-up tax guide

The commercial question is not whether the OECD GloBE rules (the Global Anti-Base Erosion rules, the international Pillar Two standard) apply to your group. For any multinational enterprise with consolidated annual revenue at or above EUR 750 million, they almost certainly do. The question is whether your Hong Kong entities are positioned to absorb the top-up tax efficiently, or whether a structural gap is quietly building a liability that will crystallise at the next filing cycle.

Hong Kong enacted its own domestic minimum top-up tax and an income inclusion rule (IIR, a top-up mechanism applied at the parent level) effective for fiscal years beginning on or after 1 January 2025. In-scope groups must now map each Hong Kong constituent entity against the GloBE effective tax rate test, assess the interaction with Hong Kong's territorial profits tax system, and determine whether the foreign-sourced income exemption regime creates an exposure rather than a relief.

This guide sets out the practical sequence for in-house counsel and CFOs working through that exercise for the first time, or revisiting a position formed before the Hong Kong rules took effect.

What is the decision the reader actually faces?

A group within scope of Pillar Two faces, at minimum, three interlocking questions about its Hong Kong operations. First: does each Hong Kong constituent entity carry sufficient substance (employees, premises, active functions) to sustain the substance-based income exclusion that GloBE permits? Second: does the territorial profits tax rate, taking into account the two-tier structure and any deductions or exclusions, produce an effective tax rate that meets or exceeds the GloBE minimum rate of 15%? Third: where is the top-up tax (the charge to bring the effective rate to 15%) collected – at the Hong Kong level under the domestic minimum top-up tax, or at the parent level under a foreign IIR?

The answers determine the group's compliance obligations, its exposure, and the order in which steps must be taken. In our cross-border tax practice, we see groups that have answered question one and question three but left question two unaddressed. That gap produces an unexpected domestic top-up charge at the first filing cycle.

The options on the table are not simply "comply" or "restructure". They include: relying on the Hong Kong domestic minimum top-up tax as a qualified domestic minimum top-up tax (QDMTT, a domestic mechanism that pre-empts a foreign IIR by collecting top-up tax locally before the parent jurisdiction can); reviewing substance and deductible amounts to improve the blended effective rate; and in some cases revisiting the classification of income flows between the Hong Kong entity and the wider group. Each option has a different sequencing logic and a different risk profile.

Step 1: Map the constituent entities and confirm scope

The first gate is a factual one. Identify every entity in Hong Kong that forms part of the consolidated group for GloBE purposes. This means Hong Kong-incorporated companies, branches, and any entity treated as fiscally transparent whose income is allocated upward to a Hong Kong constituent entity. The mapping exercise must be completed before any effective-rate calculation is attempted.

The scope test turns on whether the group's consolidated annual revenue met the EUR 750 million threshold in at least two of the four fiscal years immediately preceding the fiscal year in question. A group that crossed the threshold in a prior period and then fell below it may still be in scope for a transitional period. Groups near the threshold should verify their position each year.

The governing instrument in Hong Kong is the Inland Revenue Ordinance, as amended to incorporate the minimum top-up tax and IIR provisions. The regime operates alongside the existing profits tax framework; it does not replace it. Counsel on our desk regularly advises on the interaction between the two systems, which is not always intuitive for groups whose global tax team has built its GloBE model on a different jurisdiction's domestic implementation.

Step 2: Calculate the Hong Kong effective tax rate under the GloBE rules

Once the constituent entities are mapped, the next gate is the effective tax rate calculation for Hong Kong as a whole. GloBE applies on a jurisdictional blending basis, meaning all Hong Kong constituent entities are blended into a single effective rate figure for the jurisdiction. This is a departure from entity-by-entity profits tax thinking and it changes the logic of the analysis.

The starting point is the adjusted profits of the Hong Kong constituent entities – a figure derived from the financial accounts, not the tax return, and then subject to a series of GloBE adjustments. These include adding back deferred tax adjustments, excluding certain international shipping income, and adjusting for push-down accounting effects. The figure does not simply equal the profits tax computation.

The effective tax rate is then compared against the 15% GloBE minimum. For most Hong Kong operating entities, the standard profits tax rate of 16.5% on assessable profits above HK$2 million – and 8.25% on the first HK$2 million – suggests a headline rate above the GloBE floor. But headline is not effective. Where significant portions of income are excluded from the Hong Kong tax base under the foreign-sourced income exemption regime, or where timing differences reduce the current-year covered tax charge, the blended effective rate for the jurisdiction can fall below 15%.

The foreign-sourced income exemption (FSIE) regime has been in force since 1 January 2023. It exempts certain categories of passive income – dividends, interest, gains on disposal of equity interests, and royalties – from Hong Kong profits tax, subject to economic-substance conditions. For groups that rely on this exemption, the exempted income does not contribute to covered taxes, which directly suppresses the effective rate. This is the structural complexity that catches groups unprepared: a regime designed as a relief creates a GloBE exposure.

For a structured read on how Hong Kong's territorial and source rules interact with cross-border income flows, our analysis of the Hong Kong source and territorial position for foreign groups addresses the interaction in detail.

Step 3: Apply the substance-based income exclusion

Where the effective rate calculation shows a potential top-up liability, the next step is to assess the substance-based income exclusion available under GloBE. This exclusion reduces the excess profits subject to top-up tax by reference to the payroll costs and net carrying value of tangible assets located in the Hong Kong jurisdiction. The higher the substance, the lower the top-up exposure.

The exclusion is available to every in-scope group. It does not require a separate election. But the inputs – payroll costs of eligible employees and qualifying tangible asset values – must be computed accurately and documented. Groups that operate shared-service arrangements, secondment structures, or sub-contracted functions across the group may find that some payroll costs are not attributable to Hong Kong constituent entities in the way the GloBE computation requires.

This is where a common structural mistake occurs. In our cross-border practice, we see groups that have placed meaningful functions in Hong Kong – regional headquarters, treasury centres, intellectual property management units – but have documented those functions in contracts and intercompany arrangements that attribute the economic benefit upward to a non-HK parent. The substance is physically in Hong Kong; the documentation places it elsewhere. The GloBE rules follow the documentation as well as the economic reality. The discrepancy creates both a top-up exposure and a transfer-pricing risk.

Correcting that discrepancy before the first GloBE filing cycle is materially more straightforward than doing so under inquiry. The gate at this step is: can the group produce, from its existing records, a defensible computation of eligible payroll costs and tangible asset values for each Hong Kong constituent entity? If not, the documentation work is the priority.

How does the Hong Kong domestic minimum top-up tax interact with a foreign IIR?

If, after the substance-based income exclusion, a top-up liability remains, the next question is who collects it. Hong Kong has enacted a domestic minimum top-up tax that is intended to qualify as a QDMTT under the OECD's international framework. A QDMTT has a specific legal consequence: the top-up tax is charged and collected in Hong Kong first. The parent jurisdiction's IIR – whether in the EU, the United Kingdom, or another jurisdiction that has implemented GloBE – must credit the QDMTT collected, so that the same profits are not taxed twice to the GloBE minimum.

The QDMTT mechanism is therefore not a cost; it is a sequencing decision. The group pays top-up tax in Hong Kong rather than in the parent jurisdiction. For many groups, this is commercially preferable: the funds remain in the jurisdiction where the profits arose, the compliance is handled locally, and the parent-level IIR is satisfied. But the QDMTT qualification is a legal determination, not an automatic outcome. Groups should verify whether Hong Kong's domestic minimum top-up tax has been peer-reviewed and listed as a QDMTT under the relevant OECD guidance applicable at the time of filing.

Where a group has entities in jurisdictions that have not enacted a QDMTT – or where the domestic minimum top-up tax does not qualify – the parent's IIR applies to those jurisdictions. The ordering logic is: QDMTT first, then IIR, then the undertaxed profits rule (UTPR, a backstop charge applied by other group jurisdictions) if neither of the above captures the liability. For groups with a complex entity map spanning Hong Kong, BVI, Cayman, and the Mainland, the UTPR exposure in non-GloBE jurisdictions is a real consideration. Our briefing on treaty access between Hong Kong and the BVI addresses a related structural question that arises in this context.

Step 4: Identify the safe harbours and transitional reliefs

The OECD and the Hong Kong domestic rules include a set of safe harbours – simplification provisions that allow a group to avoid a full GloBE computation for a jurisdiction if it meets a prescribed test. The transitional country-by-country reporting safe harbour (CbCR safe harbour) is the most widely used. It allows a group to treat the top-up tax for a jurisdiction as zero if the jurisdiction passes one of three simplified tests drawn from the group's existing CbCR report: a de minimis revenue and profit test, a simplified effective tax rate test, or a routine-profits test.

The CbCR safe harbour is transitional: it applies for fiscal years beginning on or after 1 January 2025 for a defined transitional period. Groups should not assume it will remain available indefinitely. A group that relies on the safe harbour for its first compliance cycles without building the underlying GloBE computation capability is accumulating a future risk.

The permanent substance-based safe harbour is a separate mechanism for the substance-based income exclusion described at Step 3. It is not time-limited in the same way. Groups should assess which safe harbours apply to each jurisdiction in their entity map and sequence the compliance exercise accordingly.

What foreign counsel sometimes get wrong at this step is treating the transitional CbCR safe harbour as a final answer. It is a short-term procedural relief, not a structural solution. A group that clears the simplified effective tax rate test under the safe harbour because its CbCR shows a rate above 15% may find, on a full GloBE computation, that the blended rate is below 15% once the GloBE adjustments are applied. The two calculations are not the same.

Step 5: Build the compliance and reporting structure

Once the effective rate, substance exclusion, and applicable safe harbours are determined, the group must put in place the reporting infrastructure. GloBE requires the filing of a GloBE information return (GIR) in the jurisdiction where the ultimate parent entity is resident, and in some cases in the constituent entity jurisdiction as well. Hong Kong's domestic regime will require a return aligned with the GIR standard.

The practical challenge at this step is data. The GloBE computation requires financial data that is not always maintained in the form required – jurisdictional blending, GloBE adjustments to financial accounts, entity-by-entity breakdowns of deferred tax positions, and substance data for the payroll and tangible-asset computation. Groups that rely on a single ERP system may find that the system does not extract data in the required jurisdictional format without customisation.

We regularly advise on how to sequence the data-readiness exercise alongside the legal analysis. The legal question and the systems question must be solved in parallel, not sequentially. A group that waits for the legal analysis to be complete before assessing its data readiness will miss the filing cycle.

The gate at this step is: has the group designated a responsible entity for the GIR filing? In a group with a non-Hong Kong ultimate parent, the filing obligation typically sits with the ultimate parent entity, but the Hong Kong entities may also have local reporting obligations. The chain of responsibility must be documented before the first filing cycle closes.

Decision checklist: positioning your Hong Kong entities under Pillar Two

The following checklist consolidates the gates from each step. It is a diagnostic tool, not a compliance certificate. Work through it before engaging external advisers so that the engagement is focused on the live issues rather than the scoping exercise.

Has the group confirmed that its consolidated revenue met the EUR 750 million threshold in at least two of the four preceding fiscal years?
Are all Hong Kong constituent entities mapped, including branches and transparent entities?
Has the group computed the Hong Kong blended effective tax rate under GloBE (not profits tax) for the first in-scope fiscal year?
Has the impact of the FSIE regime on covered taxes been assessed specifically?
Can the group produce, from existing records, eligible payroll costs and qualifying tangible asset values for each Hong Kong constituent entity?
Is the intercompany and contractual documentation consistent with the economic substance that is physically present in Hong Kong?
Has the QDMTT qualification of Hong Kong's domestic minimum top-up tax been verified for the relevant fiscal year?
Has the group determined which safe harbours apply to Hong Kong and to which other jurisdictions in the entity map?
Is the data infrastructure in place to produce a GloBE information return on the required timetable?
Has the filing obligation and the responsible entity been formally allocated within the group?

A "no" or "unknown" answer at any line is a live issue. In our experience, groups that address these questions in the order above – entity mapping before effective-rate calculation, effective-rate calculation before safe harbour assessment, safe harbour assessment before data-readiness – complete the exercise more efficiently and with fewer retroactive corrections.

The sequence described above draws on the legal and tax position in Hong Kong and on the international GloBE framework. Our Tax Positions practice covers the full range of cross-border tax analysis for groups operating through Hong Kong, including the territorial source rules, treaty access, and the interaction of Hong Kong profits tax with offshore holding structures.

The sequence above applies to the standard configuration. Your matter depends on the specific entity map, the income flows actually booked in Hong Kong, and the parent-jurisdiction IIR – all of which require a document-based review. These are the variables that determine whether the Hong Kong QDMTT pre-empts an offshore top-up charge.

If an earlier GloBE assessment produced a result that now looks inconsistent with the domestic rules or the OECD guidance, a second read can identify the analytical gap and the steps still available before the next filing cycle.

Related practices

Holding Structures – offshore and Hong Kong holding vehicles above in-scope operating entities
Corporate Counsel – entity governance and documentation in a Pillar Two compliance context

Frequently asked questions

What does the route look like for Pillar Two and the Hong Kong minimum top-up tax for a large group?

The route moves through five gates in order: confirm scope and map constituent entities; calculate the Hong Kong blended effective tax rate under GloBE rules (not the profits tax rate); assess the substance-based income exclusion for eligible payroll and tangible assets; determine whether the Hong Kong domestic minimum top-up tax qualifies as a QDMTT to pre-empt a foreign IIR; and build the GloBE information return infrastructure. Each gate must be cleared before the next is meaningful. Groups that attempt the effective-rate calculation before the entity map is complete, or that rely on the transitional CbCR safe harbour without building the underlying computation, carry a residual risk that compounds at the first filing cycle.

Which jurisdiction's law applies to Pillar Two and the Hong Kong minimum top-up tax for a large group?

Multiple legal systems operate simultaneously. The international GloBE standard is an OECD framework, not a treaty, and has no direct legal effect; it takes effect through domestic legislation in each jurisdiction. In Hong Kong, the governing instrument is the Inland Revenue Ordinance, as amended to introduce the minimum top-up tax and income inclusion rule for fiscal years beginning on or after 1 January 2025. The parent jurisdiction's IIR – in the EU, the United Kingdom, or another implementing state – applies to the ultimate parent entity. The interaction between the two domestic regimes, and the QDMTT mechanism that sequences their application, is the central legal question for groups with Hong Kong constituent entities and a non-Hong Kong ultimate parent.

Do I need a Hong Kong adviser for Pillar Two and the Hong Kong minimum top-up tax for a large group?

A group that relies exclusively on its global tax team or its parent-jurisdiction advisers to assess the Hong Kong position risks missing the specific interaction between the FSIE regime and the GloBE effective-rate calculation – a domestic nuance that routinely produces an unexpected result. Hong Kong's territorial system, the two-tier profits tax structure, and the FSIE substance conditions all feed into the GloBE effective rate in ways that require a Hong Kong-specific read. Cross-border counsel familiar with both the domestic rules and the international GloBE framework is the appropriate starting point, working alongside the group's existing global tax advisers on the overall filing strategy.

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This publication is general information and does not constitute legal advice. For advice on your situation, contact info@lockhartyip.com.

Pillar Two and the Hong Kong minimum top-up tax for a large group: a step-by-step guide