Pillar Two safe harbours: what changes in 2026
A breakdown of the transitional safe harbour rules and what multinational groups need to reassess before they expire.
Transitional safe harbours have given multinational groups breathing room while they build out full Pillar Two data collection and calculation processes. That runway is starting to narrow, and groups that have leaned heavily on simplified reporting need a plan for what comes after it.
What the transitional rules covered
The transitional safe harbours were designed to reduce compliance burden in the early years of Pillar Two, allowing qualifying jurisdictions to rely on country-by-country reporting data and simplified effective tax rate tests rather than a full GloBE computation. For groups operating across dozens of jurisdictions, this materially reduced the initial lift.
In practice, most groups treated the transitional period as a chance to stand up governance and tooling in parallel with simplified filings, rather than front-loading every jurisdiction's full calculation on day one.
The groups in the strongest position now are the ones that used the transitional window to build real infrastructure, not just to file the minimum.
What to reassess now
As jurisdictions move off transitional relief on their own timelines, the calculation basis shifts from CbCR-derived estimates to full GloBE income and covered taxes computations. That change in basis can move an entity's effective tax rate meaningfully, even where nothing about the underlying business has changed.
Groups should be re-running exposure analysis jurisdiction by jurisdiction, rather than assuming last year's safe harbour result will hold. Entities that comfortably cleared the simplified ETR test can still fall short under a full computation once timing differences, deferred tax adjustments, and permanent differences are brought into scope.
Practical next steps
A useful starting point is a jurisdiction-level gap analysis: which entities are still protected by a safe harbour today, which lose that protection in the next filing cycle, and what data gaps exist for a full computation. From there, prioritise the jurisdictions with both the largest financial exposure and the least calculation readiness.