Pillar Two: Legal Definition and Meaning

Pillar Two is the second component of the OECD/G20 Inclusive Framework';s two-pillar solution to address the tax challenges arising from the digitalisation and globalisation of the economy. It establishes a global minimum effective tax rate of 15% for large multinational enterprise groups with annual consolidated revenues of at least EUR 750 million. Where a constituent entity pays less than 15% effective tax in a given jurisdiction, the framework triggers top-up taxes to bring the overall rate to the minimum threshold. This guide explains the legal definition of Pillar Two, its core rules, how it is implemented in domestic law, and what it means in practice for international business structures.

Pillar Two is formally known as the Global Anti-Base Erosion Rules, commonly abbreviated as GloBE Rules. The OECD published the GloBE Model Rules in late 2021, followed by detailed Commentary and Administrative Guidance. These instruments do not themselves have the force of law; they are model legislation that participating jurisdictions transpose into their domestic legal systems. Once enacted domestically, the rules become binding on in-scope groups operating in that jurisdiction.

The legal architecture rests on a single core principle: if a large multinational group pays an effective tax rate below 15% in any jurisdiction, a top-up tax is collected somewhere in the group';s structure to make up the shortfall. The framework identifies three mechanisms for collecting that top-up tax, each with a defined order of priority. Understanding which mechanism applies in a given situation is the central practical question for tax and legal advisers.

The term "pillar two" therefore refers simultaneously to the OECD model framework, to the domestic legislation enacted in conformity with it, and to the broader policy objective of establishing a global tax floor. In legal documents, contracts and compliance filings, the term is used to describe obligations arising under any of these layers.

The GloBE Rules operate through three distinct charging mechanisms, each with its own legal basis and priority.

The first is the Qualified Domestic Minimum Top-up Tax, commonly called QDMTT. A jurisdiction may enact a domestic top-up tax that applies to its own low-taxed constituent entities before any foreign top-up tax can be levied. A QDMTT that meets the OECD';s qualification criteria takes priority over the other mechanisms. Many jurisdictions have introduced QDMTTs precisely to retain the top-up tax revenue domestically rather than allowing it to flow to a parent jurisdiction.

The second mechanism is the Income Inclusion Rule, or IIR. Under the IIR, the ultimate parent entity of a multinational group is required to pay a top-up tax in its jurisdiction of residence on the low-taxed income of its constituent entities elsewhere. If the ultimate parent jurisdiction has not enacted an IIR, the obligation cascades down to intermediate parent entities in jurisdictions that have enacted the rule. The IIR is the primary top-up mechanism after any applicable QDMTT.

The third mechanism is the Undertaxed Profits Rule, or UTPR. The UTPR operates as a backstop. Where neither a QDMTT nor an IIR has collected the full top-up tax, the UTPR allows other jurisdictions in which the group has constituent entities to collect the residual amount. The UTPR is allocated among those jurisdictions based on a formula that references employees and tangible assets. The UTPR is intended to apply only where the primary mechanisms have failed to collect the full top-up tax.

The effective tax rate, or ETR, under the GloBE Rules is calculated on a jurisdiction-by-jurisdiction basis, not at the level of individual entities. The ETR for a jurisdiction is the ratio of adjusted covered taxes to GloBE income or loss for all constituent entities located in that jurisdiction.

GloBE income is derived from the financial accounting net income or loss of each constituent entity, subject to a defined set of adjustments. These adjustments include, among others, the exclusion of dividends from qualifying participations, the exclusion of gains and losses on equity interests, and adjustments for certain timing differences. The rules also include a Substance-Based Income Exclusion, which carves out a portion of income attributable to payroll costs and the carrying value of tangible assets. This exclusion reduces the amount of income subject to the top-up tax calculation and is intended to avoid penalising genuine economic activity.

Covered taxes are the income taxes reflected in the financial statements of the constituent entities, subject to further adjustments for deferred tax and certain other items. The treatment of deferred tax under the GloBE Rules is technically complex. The rules introduce a concept called the Deferred Tax Liability recapture mechanism, which prevents groups from using deferred tax liabilities to inflate their ETR temporarily and then avoid top-up tax when those liabilities reverse.

A common mistake among finance teams encountering the GloBE Rules for the first time is to assume that the ETR under the GloBE Rules will closely track the ETR reported in the group';s financial statements or country-by-country report. In practice, the GloBE adjustments can produce materially different results, and groups should model their GloBE ETR separately.

The GloBE Model Rules are designed to be implemented as common approach legislation, meaning that jurisdictions are not obliged to adopt them but, if they do, they must conform to the model. This design creates a degree of legal certainty for multinationals: a QDMTT or IIR enacted in conformity with the model will be recognised by other jurisdictions as qualified, triggering the priority rules described above.

In practice, domestic implementation varies in several respects. Some jurisdictions have enacted the IIR and QDMTT together. Others have enacted only the QDMTT, choosing not to impose an IIR on outbound investments. A smaller number have enacted the UTPR as well. The scope of domestic legislation may also differ in how it handles transitional safe harbours, which are temporary simplifications that reduce compliance burdens for groups in the early years of the regime.

The OECD has published a series of Administrative Guidance documents that clarify how specific provisions of the Model Rules should be interpreted. Domestic legislation that was enacted before a particular piece of Administrative Guidance was published may not reflect the latest interpretation. Legal advisers must therefore check both the domestic statute and the current state of OECD guidance when advising on a specific transaction or structure.

For groups with operations in jurisdictions that have not yet enacted GloBE legislation, the analysis does not end. If the group';s ultimate parent is resident in a jurisdiction with an IIR, the parent jurisdiction may still impose top-up tax on low-taxed income arising in the non-implementing jurisdiction. The absence of local GloBE legislation does not create a safe harbour.

If you are assessing how Pillar Two affects your group';s existing structure, we can assist with a preliminary exposure analysis. Contact us at info@vlolawfirm.com.

Not all multinational groups fall within the scope of the GloBE Rules. The primary threshold is annual consolidated revenue of at least EUR 750 million in at least two of the four fiscal years immediately preceding the tested fiscal year. This threshold mirrors the threshold used for country-by-country reporting under the OECD';s BEPS Action 13.

Certain entities are excluded from the definition of constituent entity even where the group as a whole is in scope. Excluded entities include governmental entities, international organisations, non-profit organisations, pension funds, and investment funds that are the ultimate parent entity of a group. Constituent entities that are owned by excluded entities may also benefit from partial exclusions in defined circumstances.

The GloBE Rules include a series of safe harbours that reduce compliance obligations for groups or jurisdictions meeting certain conditions. The most significant is the transitional country-by-country reporting safe harbour, which allows groups to use simplified data from their existing country-by-country report to determine whether a jurisdiction is likely to be below the 15% threshold. Where the safe harbour applies, no detailed GloBE ETR calculation is required for that jurisdiction in the relevant period. This safe harbour is transitional and applies only for a defined initial period of the regime.

A non-obvious requirement that many groups overlook is the need to track which jurisdictions have enacted qualified IIRs and QDMTTs. The qualification status of a jurisdiction';s rules affects the priority of collection and, therefore, where the top-up tax liability ultimately sits within the group. Groups should maintain a live map of implementation status across all jurisdictions in which they have constituent entities.

Scenario one: a holding company in a low-tax jurisdiction. Consider a multinational group with an ultimate parent in a high-tax jurisdiction and an intermediate holding company in a jurisdiction with a low statutory corporate tax rate. The holding company earns passive income - dividends and interest - from subsidiaries. Under the GloBE Rules, the ETR for the holding company';s jurisdiction is calculated on all GloBE income of constituent entities located there. If the ETR falls below 15%, the ultimate parent';s jurisdiction will impose an IIR top-up tax on the shortfall, assuming it has enacted a qualified IIR and no QDMTT applies in the holding company';s jurisdiction. The practical effect is that the tax benefit of routing income through the low-tax holding company is substantially reduced or eliminated.

Scenario two: a manufacturing subsidiary with significant tangible assets. A group operates a manufacturing subsidiary in a jurisdiction with a statutory tax rate of 12%. The subsidiary employs a large workforce and holds substantial tangible assets. Under the Substance-Based Income Exclusion, a portion of the subsidiary';s GloBE income is carved out based on 5% of the carrying value of eligible tangible assets and 5% of eligible payroll costs. If the excluded amount is large relative to total GloBE income, the effective top-up tax obligation may be modest or zero, even though the statutory rate is below 15%. This illustrates that the GloBE ETR and the top-up tax liability depend heavily on the specific asset and payroll profile of each jurisdiction, not merely on the statutory rate.

In practice, founders and finance directors of mid-sized groups approaching the EUR 750 million revenue threshold should begin modelling their GloBE exposure before they cross it. Waiting until the threshold is breached leaves insufficient time to restructure or implement compliant reporting systems.

What is the difference between Pillar One and Pillar Two?

Pillar One and Pillar Two are the two components of the OECD/G20 two-pillar solution, but they address different problems. Pillar One reallocates a portion of the taxing rights over the residual profits of the largest and most profitable multinationals to market jurisdictions where customers are located, regardless of whether the group has a physical presence there. Pillar Two, by contrast, does not reallocate taxing rights; it establishes a minimum effective tax rate floor of 15% and allows jurisdictions to collect top-up taxes where that floor is not met. The two pillars are legally and technically independent. A group may be in scope of Pillar Two without being subject to any Pillar One reallocation, and vice versa. Implementation timelines and domestic legislation for the two pillars have also diverged significantly, with Pillar Two advancing more rapidly.

When does a group need to start complying with Pillar Two, and what are the filing obligations?

Compliance obligations depend on when the jurisdiction in which the group';s ultimate parent or constituent entities are located has enacted GloBE legislation and for which fiscal years it applies. Most early-adopting jurisdictions have enacted rules that apply from fiscal years beginning on or after a specified date in recent years. The primary filing obligation is the GloBE Information Return, a standardised report that groups must file with the tax authority in each jurisdiction where they have a filing obligation. The GloBE Information Return is detailed and requires jurisdiction-by-jurisdiction ETR calculations. Many jurisdictions allow a designated filing entity to file on behalf of the group. Penalties for late or incorrect filing vary by jurisdiction but can be substantial. Groups should identify their filing jurisdictions and establish data collection processes well in advance of the first filing deadline.

Can a group restructure to reduce its Pillar Two exposure?

Restructuring to reduce GloBE top-up tax is legally permissible but technically complex. The most straightforward lever is the Substance-Based Income Exclusion: increasing eligible payroll or tangible assets in a low-tax jurisdiction reduces the GloBE income subject to the top-up calculation. However, such changes must reflect genuine economic substance and not be purely tax-motivated, both because the GloBE Rules themselves are designed to reward substance and because other anti-avoidance rules - including transfer pricing and general anti-avoidance provisions - continue to apply. Restructuring the group';s legal entity structure, for example by moving the ultimate parent to a jurisdiction with a qualified IIR, can affect where top-up tax is collected but does not reduce the total amount owed if the underlying ETR remains below 15%. Legal and tax advisers should model the full GloBE impact of any proposed restructuring before implementation.

Pillar Two is a fundamental shift in the international tax framework, establishing a 15% global minimum effective tax rate for large multinationals through a layered system of domestic and cross-border top-up taxes. Its legal meaning encompasses the OECD GloBE Model Rules, domestic implementing legislation, and the administrative guidance that continues to evolve. Groups in scope face new compliance obligations, ETR modelling requirements, and potential top-up tax liabilities that depend on their specific jurisdictional footprint and asset profile.

VLO Law Firms advises international clients on Pillar Two compliance, exposure analysis, and structuring matters across multiple jurisdictions. We can assist with GloBE ETR modelling, review of domestic implementing legislation, assessment of safe harbour eligibility, and preparation of GloBE Information Returns. To request a consultation, contact: info@vlolawfirm.com