OECD Pillar Two: Final Implementation Guidance

The OECD released its consolidated administrative guidance on the Global Anti-Base Erosion (GloBE) rules in early 2026, addressing several contested interpretive questions that had created uncertainty for multinational groups attempting to implement compliant systems. The guidance clarifies the treatment of deferred tax assets arising from carry-forward losses under the GloBE computation, confirming that such assets are recoverable only to the extent they are expected to reverse within five years — a position that will materially affect the effective tax rate calculations of groups with historical loss positions in low-tax jurisdictions.

The Undertaxed Profits Rule (UTPR) allocation mechanism has been further refined, with the final guidance introducing a safe harbour for groups whose constituent entities in a jurisdiction have a combined GloBE ETR above 20% on a three-year average basis. This administrative simplification significantly reduces the compliance burden for groups operating in stable, moderate-tax environments, and will allow many multinationals to exclude entire jurisdictions from detailed GloBE calculations during the transitional period through 2026. Groups should model whether their jurisdictions qualify before investing in full data infrastructure.

From a planning perspective, the guidance's treatment of substance-based income exclusions warrants careful review. The payroll and tangible asset carve-outs have been recalibrated with updated phase-down percentages, reducing the exclusion to 7.8% of payroll costs and 5.0% of net book value of tangible assets from fiscal year 2026 onwards. Groups that have structured operations to maximise substance exclusions should remodel their GloBE ETR projections to reflect these reductions and assess whether existing low-tax jurisdictions retain their incentive economics once the recalibrated carve-outs are applied.

Compliance teams should also note the updated GloBE Information Return filing timeline. The final guidance confirms that returns for fiscal year 2025 must be filed by 31 March 2026 in designated filing jurisdictions, with a 15-month transition extension available for first-year filers. INNOVATIVE NATIONAL TAX & UPKEEP INTERNATIONAL TALLY PTY LTD's Global Tax Practice is advising clients to begin data collection and system readiness assessments immediately, given the complexity of sourcing jurisdiction-level financial data from ERP systems not originally designed for GloBE reporting. Early engagement with technology vendors and internal finance teams is critical to meeting these deadlines.