More than 140 countries have agreed to the Organisation for Economic Co‑operation and Development’s (OECD) Pillar Two, and over 50 countries have already enacted Global Minimum Tax (GMT) into domestic law. The direction of travel is clear.
For Australian‑headquartered groups and inbound multinationals, this shift lands squarely across tax provision, financial reporting, data governance, and audit readiness. It’s no longer just about future compliance. It’s about what you can explain – clearly and consistently – today.
As one tax leader describes it:
“A sea of change to global taxation, resulting in an upheaval in international tax rules not seen for almost 100 years.”
This whitepaper brings together perspectives from global tax, finance, and technology leaders to unpack what GMT really means in practice, and how organisations are responding.
Why Pillar Two is proving so hard to execute
At the centre of GMT is a data problem.
To determine scope, calculate top‑up tax, and complete the GloBE Information Return (GIR), multinational groups must collect 200+ data points by entity and jurisdiction. That data spans finance, tax, HR, legal, and operational systems—often owned by different teams, in different formats, across different countries.
The challenge is amplified by local variation. Countries are implementing Pillar Two at different times, with different combinations of Qualified Domestic Minimum Top‑Up Tax (QDMTT), Income Inclusion Rule (IIR), and Undertaxed Profits Rule (UTPR), plus elections, deviations, and transitional safe harbours. Calculations must follow a strict sequence, and often need to be rerun throughout the year.
As Melvin Song, Head of Tax at CapitaLand Investments, explains:
“This absence of a standardised or automated system presents a significant challenge in transitioning from a pre‑Pillar Two world to a post‑Pillar Two world, where tax provisioning is crucial for calculating the Effective Tax Rate (ETR).”
What this means for Australian tax teams
- Pillar Two impacts tax provision and IAS 12 disclosures, not just returns.
- Boards and auditors will expect clear explanations of effective tax rate (ETR) movements.
- Data gaps and manual workarounds increase ATO, audit, and reputational risk.
- Consistency across jurisdictions matters—especially when figures roll up to Australia.
The compliance impact goes well beyond the tax return
Global Minimum Tax affects far more than annual filings.
Australian tax teams must now factor Pillar Two into:
- Quarterly and annual tax provision
- Financial statement disclosures
- Audit queries and documentation
- Board and executive reporting
The GIR alone is a 20+ page return, requiring significantly more information than Country‑by‑Country Reporting (CbCR).
As Arijit Ganguly, Senior VP & Group Head – Taxation at Mphasis, notes:
“It requires an extensive amount of information, far exceeding what is needed for reports such as Country‑by‑Country (CBCR).”
For many Australian groups, the first real pressure point won’t be the return deadline. It will be explaining Pillar Two outcomes in the tax provision – and standing behind those numbers.
Why technology is no longer optional
Manual approaches don’t scale to the complexity, volume, or frequency of GMT calculations. Yet many tax functions are still playing catch‑up.
According to Thomson Reuters research in 2025, 58% of tax departments are under-resourced, and 59% lack confidence they can upgrade tax tech in the next two years.
In practice, that often means spreadsheets, manual reconciliations, and limited visibility when questions arise.
Tax leaders are blunt about the risk. According to Vinoy Krishna, Head of Global Tax, Tata Communications, “Without systematic automation, this change may not be possible”.
What leading teams are focusing on now
- Centralised, audit‑ready data for Pillar Two and tax provision
- Country‑specific rule tracking and calculation sequencing
- Automation that supports quarterly close timelines
- Clear outputs that stand up to auditor and regulator scrutiny
What you’ll gain from this whitepaper
Shifting Dynamics in Global Taxation draws on interviews with senior tax leaders and research from Thomson Reuters, Orbitax, and the OECD to explore:
- The real‑world challenges of Pillar Two implementation
- Why data, process, and technology decisions matter more than ever
- How leading organisations are planning for compliance and disclosure
- Practical lessons for reducing risk and disruption
If GMT applies to your organisation, this isn’t a future problem. It’s already shaping decisions.
Download the whitepaper to understand what Pillar Two means for your data, your calculations, and your reporting – and how tax leaders are preparing now.
