OECD Pillar Two Explained: The Ultimate Guide to Global Minimum Tax

Updated April 2026

OECD Pillar Two introduces a 15% global minimum tax designed to ensure that large multinational enterprises pay a minimum level of tax regardless of where they operate. For decades, companies could shift profits to low-tax jurisdictions. Pillar Two changes that by ensuring that income taxed below 15% is subject to a top-up tax.

What Is OECD Pillar Two?

OECD Pillar Two is part of the broader BEPS 2.0 initiative. Its objective is to reduce tax avoidance by establishing a minimum effective tax rate of 15%.

It applies to:

• Multinational groups
• Annual revenue above €750 million

Why Was Pillar Two Introduced?

The traditional international tax system struggled to keep up with the structure of modern multinational groups.

Key pressures included:

• Digital business models
• Intangible assets
• Cross-border profit shifting

Significant global tax revenue losses were attributed to base erosion and profit shifting. Pillar Two aims to:

• Reduce tax avoidance
• Improve fairness
• Stabilize global tax competition

How the Global Minimum Tax Works

At a high level, the system works as follows:

1. Calculate the Effective Tax Rate (ETR) for each jurisdiction
2. Identify jurisdictions where ETR is below 15%
3. Apply a top-up tax to the difference
4. Allocate that tax using global rules

The Three Core Rules of Pillar Two

1. Income Inclusion Rule (IIR)

The primary rule.

If a subsidiary is taxed below 15%, the parent company’s jurisdiction collects the difference.

2. Undertaxed Profits Rule (UTPR)

The backup rule.

If the IIR is not applied, other jurisdictions step in to collect the tax.

3. Qualified Domestic Minimum Top-up Tax (QDMTT)

The local rule.

Countries can collect the top-up tax domestically before others do.

Effective Tax Rate (ETR)

The Effective Tax Rate determines whether additional tax is required.

If the ETR is below 15%, a top-up tax is triggered.

Example

A subsidiary is taxed at 10% in a jurisdiction where the minimum rate is 15%.

A 5% top-up tax applies.

This tax can be collected by:

• The parent jurisdiction (IIR)
• Other jurisdictions (UTPR)
• The local jurisdiction (QDMTT)

Why Pillar Two Matters

Reduced Incentive for Profit Shifting

Low-tax jurisdictions provide less structural advantage than they did under earlier planning models.

Increased Transparency

Standardized reporting increases visibility across jurisdictions and makes low-tax outcomes more visible.

Shift in Tax Strategy

Tax becomes more of a constraint than a primary planning tool. The challenge moves from pure structuring to execution, data, and operating model design.

Conclusion

OECD Pillar Two establishes a global tax floor. It does not eliminate tax planning, but it fundamentally changes how multinational groups approach tax strategy.