The Global Anti-Base Erosion Model Rules – commonly referred to as Pillar Two or GloBE Rules – are part of the OECD/G20 Inclusive Framework’s initiative to ensure large multinational enterprises (MNEs) pay a minimum effective tax rate on their global profits. Over 135 jurisdictions have adopted or signed up to implement these rules to address tax base erosion in today’s globalised economy.  

Pillar Two is anchored in a global minimum tax framework that applies to MNE groups (those with consolidated revenues of €750 million or more in their consolidated financial statements) and includes comprehensive rules for calculating top-up taxes based on applying a minimum tax rate of 15%, as well as Group and local filing requirements. 

If your organisation is part of an MNE group affected by Pillar Two (by revenue thresholds and jurisdictions adopting the rules), you will face obligations to calculate top-up tax, prepare and file a GloBE Information Return, and meet specific local filing requirements. Many jurisdictions began applying the GloBE Rules through their tax legislation to fiscal years starting on 1 January 2024, with 30 June 2026 being a critical deadline for robust compliance processes and reporting readiness.  

Tax teams should prioritise data collection, calculation methodology, and reporting readiness now to meet this deadline with confidence and minimise risk. 

Pillar Two requires:  

• Multijurisdictional data aggregation across group entities.  

• Detailed top-up tax calculations based on local legislation implementing the GloBE Rules. 

• Structured reporting in the XML-based GloBE Information Return, and local jurisdictional filing requirements. 

• Awareness of local deviations or additional local legislation beyond the model rules. 

Together, these demands expand well beyond traditional annual compliance and can quickly overwhelm manual processes without automation and built-in logic that reflects ongoing administrative guidance.

Excel is excellent for preliminary analysis but has significant limitations for Pillar Two:  

• Manual data entry increases risk of errors - especially in complex, multi-jurisdictional calculations.  

• Lack of audit trail and version control makes governance and review difficult.  

• Static templates don’t adapt to evolving OECD Guidance or local requirements.  

• No built-in GloBE logic or tax rule engine to automate core calculations or produce compliant outputs.  

Given the volume of entities, iterations of calculations, and emerging administrative guidance, Excel alone is unlikely to be sufficient for robust, auditable compliance.  

A purpose-built platform such as Tax Systems’ Pillar2 offers a range of advantages over manual approaches: 

• Automated, rule-based calculations that align with the OECD Model Rules and local variations.  

• Support for top-up tax calculations for the application of the GloBE Rules for Income Inclusion Rules (IIR), Domestic Minimum Top-up Tax (DMTT) and Undertaxed Payments (Profits) Regime (UTPR) top-up taxes,  

• GloBE Information Return preparation, and local IIR, DMTT and UTPR filings using a single source of data.  

• Data integration and reuse, eliminating repeated imports, reducing redundancies and providing consistency. 

• Auditability, version control, and clear control frameworks, which are essential during reviews or tax authority queries.  

• Integration with broader tax compliance engines (e.g., TaxSuite), enabling seamless workflow across other international tax obligations.  

This results in greater accuracy, scalability, governance strength, and compliance confidence compared with manual spreadsheets. 

Platforms like Pillar2:  

• Track data lineage from source values to final outputs.  

• Maintain transparent audit trails and calculation logic.  

• Store scenario analyses and version history.  

• Provide documentation support for filings.  

These capabilities support both internal governance needs and external audit or tax authority scrutiny, enhancing control across your compliance lifecycle – something that manual spreadsheets cannot reliably provide.  

Beyond compliance mechanics, Pillar2 offers insight tools (including GenAI-driven tax data insights) that help tax leaders:  

• Understand tax risk exposure and hot spots.  

• Run scenario analysis on different calculation methodologies.  

• Forecast potential top-up tax liabilities under various operational scenarios.   

This strategic intelligence supports decision-making and planning – far beyond Excel’s static capabilities. 

Action steps your team can take today:  

• Audit your entity data and tax reporting infrastructure.  

• Map existing processes to GloBE Rule requirements and jurisdictions where your business operates.  

• Evaluate software platforms capable of automating calculations, controlling data, and supporting structured reporting.  

• Build cross-functional processes with finance, accounting, and IT to streamline data flows.  

• Engage stakeholders early to avoid last-minute scramble.  

Technology that centralises and automates Pillar Two compliance will be critical to delivering results efficiently and defensibly under deadline pressure.