Thoughts
A structured archive of writing on Pillar Two, tax technology, data, and AI. The goal is not a simple chronological blog, but a growing body of connected work that is easy to navigate by topic.
OECD Pillar Two Explained: The Ultimate Guide to Global Minimum Tax
A broad, practical guide to the 15% global minimum tax, including why it was introduced, how the regime works, and the role of the IIR, UTPR, and QDMTT.
Read the guide →Pillar Two Safe Harbours: Transitional Relief, Tightening Tests, and Why 2026 Matters
Supporting article on transitional simplification, the CbCR safe harbour tests, and why the remaining transition window matters.
Open article →Pillar Two Fundamentals
Core concepts, charging rules, and the basic mechanics of the global minimum tax regime.
- Pillar Guide OECD Pillar Two Explained: The Ultimate Guide to Global Minimum Tax Broad foundation article covering the purpose, mechanics, and core rules.
- Supporting Article Income Inclusion Rule (IIR): How Pillar Two Top-Up Tax Is Collected Focused article on the primary charging rule and how top-up tax is collected at parent level.
- Supporting Article Undertaxed Profits Rule (UTPR): How Residual Pillar Two Top-Up Tax Is Collected Focused article on the backstop rule and how residual top-up tax is allocated across UTPR jurisdictions.
- Supporting Article Qualified Domestic Minimum Top-up Tax (QDMTT): How Jurisdictions Retain Pillar Two Tax Rights Focused article on how jurisdictions collect top-up tax locally before foreign rules apply.
- Supporting Article Top-Up Tax Explained: How the Pillar Two 15% Minimum Is Calculated Focused article on the jurisdictional calculation of the shortfall and resulting top-up tax amount.
- Supporting Article Effective Tax Rate (ETR) Under Pillar Two: How Low-Tax Outcomes Are Measured Focused article on how the jurisdictional ETR is measured and how it triggers top-up tax analysis.
- Supporting Article Substance-Based Income Exclusion (SBIE): Why Not All Profit Is Subject to Pillar Two Focused article on how routine returns linked to payroll and tangible assets reduce the profit exposed to top-up tax.
- Supporting Article Pillar Two Rule Order Explained: How QDMTT, IIR, and UTPR Interact Focused article on how taxing rights are allocated in sequence across QDMTT, IIR, and UTPR.
- Supporting Article Pillar Two Safe Harbours: Transitional Relief, Tightening Tests, and Why 2026 Matters Focused article on transitional simplification, tightening thresholds, and the move toward full GloBE compliance.
AI in Tax
Practical writing on how AI changes documentation, workflow, reasoning, and operating model design in tax work.
- Pillar Guide AI in Tax: A Practical Operating Model View Upcoming anchor article on where AI adds real value in tax and where it creates noise.
- Supporting Article Using AI for Requirement and Design Documentation Upcoming article on turning AI into a structured drafting partner rather than a distraction engine.
Pillar Two Data & Implementation
Data readiness, systems design, reporting architecture, and the implementation questions that determine whether compliance is sustainable.
Standalone Notes
Shorter pieces, observations, and narrower views that support the broader archive without needing full cluster structure.
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April 2026Pillar Two Safe Harbours: Transitional Relief, Tightening Tests, and Why 2026 Matters Supporting article in the Pillar Two Fundamentals cluster.
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April 2026Pillar Two Rule Order Explained: How QDMTT, IIR, and UTPR Interact Supporting article in the Pillar Two Fundamentals cluster.
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April 2026Substance-Based Income Exclusion (SBIE): Why Not All Profit Is Subject to Pillar Two Supporting article in the Pillar Two Fundamentals cluster.
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April 2026Effective Tax Rate (ETR) Under Pillar Two: How Low-Tax Outcomes Are Measured Supporting article in the Pillar Two Fundamentals cluster.
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April 2026Top-Up Tax Explained: How the Pillar Two 15% Minimum Is Calculated Supporting article in the Pillar Two Fundamentals cluster.
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April 2026Qualified Domestic Minimum Top-up Tax (QDMTT): How Jurisdictions Retain Pillar Two Tax Rights Supporting article in the Pillar Two Fundamentals cluster.
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April 2026Undertaxed Profits Rule (UTPR): How Residual Pillar Two Top-Up Tax Is Collected Supporting article in the Pillar Two Fundamentals cluster.
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April 2026Income Inclusion Rule (IIR): How Pillar Two Top-Up Tax Is Collected Supporting article in the Pillar Two Fundamentals cluster.
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April 2026OECD Pillar Two Explained: The Ultimate Guide to Global Minimum Tax Pillar page for the Pillar Two Fundamentals cluster.