BEPS Pillar Two: The Global Minimum Tax Explained

A clear guide to BEPS Pillar Two and the 15% global minimum tax: who is in scope, how the GloBE rules work, and what it means for offshore structures.

For decades, multinational groups could route profits through low-tax jurisdictions and bring their overall effective tax rate well below the headline rates of the countries where they really operated. The OECD's response, developed under its Base Erosion and Profit Shifting project, is the most significant change to international tax coordination in a generation.

BEPS Pillar Two introduces a global minimum tax of 15 per cent on the profits of large multinational groups, wherever those profits are booked. The mechanism is technical, but the headline is simple: if a group's profits in a jurisdiction are taxed below 15 per cent, a top-up tax is collected to bring the rate up to that floor.

For owners of cross-border structures, and for anyone relying on low-tax jurisdictions, this changes the calculus. This guide explains who is caught, how the rules operate, and what it means in practice.

Who Is Actually in Scope

The most important point, and the most reassuring for many readers, is that Pillar Two is aimed at large multinational enterprise groups, not at individuals, family investment structures or modest businesses.

The rules apply to groups with consolidated annual revenue at or above EUR 750 million in at least two of the four preceding years, mirroring the threshold already used for country-by-country reporting. Groups below that size are outside the GloBE rules entirely.

Certain entities are excluded even within large groups, including government entities, international organisations, non-profit organisations, pension funds, and certain investment and real estate investment vehicles that sit at the top of a group. The treatment of investment funds and holding structures is nuanced and depends on the precise facts.

So a private family holding company, a single founder's offshore company, or a mid-sized trading group will generally not be in scope. A genuinely global enterprise with revenue above the threshold almost certainly will be, regardless of how its ownership is arranged.

How the GloBE Rules Work

The Global Anti-Base Erosion rules, known as GloBE, work by calculating an effective tax rate for each jurisdiction in which a group operates, then topping up where that rate falls below 15 per cent.

The calculation starts from financial-accounting profit, adjusted under detailed rules, and divides covered taxes by that adjusted income to produce a jurisdictional effective rate. Where the rate is below 15 per cent, a top-up tax equal to the shortfall is imposed on the relevant profits, after deducting a substance-based carve-out.

That substance-based income exclusion is significant. It removes from the top-up base a return calculated on the group's tangible assets and payroll in the jurisdiction. The logic is that the regime targets undertaxed mobile profit, not genuine economic activity, so a business with real people and real assets in a location shelters part of its income from the top-up.

The top-up is then collected through a hierarchy of charging mechanisms. The primary rule is the Income Inclusion Rule, under which the parent entity's jurisdiction collects the top-up on undertaxed foreign profits. A backstop, the Undertaxed Profits Rule, allows other jurisdictions to collect any top-up not picked up by the income inclusion rule. Separately, a jurisdiction may enact a Qualified Domestic Minimum Top-up Tax, which lets the low-tax country itself collect the top-up first, keeping the revenue at home.

Why the QDMTT Changes Offshore Reality

That domestic top-up tax is the quiet revolution for traditional offshore centres. Faced with the prospect of other countries collecting top-up tax on profits booked in their territory, many low-tax and zero-tax jurisdictions have introduced their own qualified domestic minimum top-up taxes.

The practical effect is that a number of classic zero-tax jurisdictions now levy a 15 per cent charge on in-scope multinational groups operating there, simply so that the revenue does not flow abroad. For affected groups, the tax advantage of booking profit in those locations is neutralised at the floor.

This does not abolish offshore structuring. It reshapes its purpose. For large groups, the rationale shifts away from rate arbitrage toward non-tax advantages: legal certainty, neutral treatment of multi-jurisdiction investors, asset protection, regulatory access and operational convenience. For groups below the threshold, the low-rate advantage remains intact.

Timing and Implementation

Pillar Two is not a single global statute but a coordinated model that each country enacts in its own law. Implementation has rolled out in waves, with the European Union, the United Kingdom and many others bringing the income inclusion rule and domestic top-up taxes into effect first, and the undertaxed profits backstop following.

Because adoption is staggered, the precise rules, effective dates and transitional safe harbours vary by jurisdiction. There are transitional simplifications, including a country-by-country reporting safe harbour that can switch off detailed calculations for lower-risk jurisdictions in the early years. The position of the United States, which operates its own minimum-tax regime, remains a distinct and evolving question that affects how US-parented groups interact with the global rules.

The consequence for planning is that there is no single answer; the analysis depends on where a group is parented, where it operates, and which countries have enacted what, as at the relevant year.

What It Means in Practice

For in-scope multinationals, the work is largely compliance and modelling: identifying which jurisdictions fall below the floor, computing the effective tax rate under GloBE principles, claiming the substance carve-out, and filing the GloBE information return. The data demands are considerable and often require new systems.

For privately held groups and individuals below the threshold, the message is one of perspective. Pillar Two does not touch you directly, but it reflects a wider direction of travel: rate-only strategies are losing ground to substance, transparency and genuine economic presence. Structures should be built to withstand that environment, not the one that existed a decade ago.

How HPT Helps

We help clients understand whether they are in scope at all, which spares many the anxiety the headlines provoke, and we model the impact for groups that are. Where structures were built around low headline rates, we reassess them against the post-Pillar-Two reality, prioritising substance, certainty and defensibility. Working alongside specialist tax advisers, we help redesign cross-border arrangements so they remain efficient and resilient.

If you are unsure how the global minimum tax affects your structure, speak to us for a clear assessment.