Calculating the estimated tax under Pillar One is only half the story, given Pillar One cannot be viewed in isolation.

After calculating the Pillar One reallocation and estimated corporate income tax, the Pillar Two impact can also be considered, given Pillar One feeds directly into Pillar Two. 

When both Pillar One and Pillar Two are implemented, Pillar One will apply before Pillar Two, and any Pillar One tax liability will be considered when calculating the effective tax rate for Pillar Two purposes. This will then impact on the top-up tax calculation for any low-taxed jurisdictions. 

The modelling tool allows some additional jurisdictional financial details to be added in for Pillar Two purposes,  and it then calculates the consolidated position taking account of both Pillar One and Pillar Two, to estimate the final top-up tax liability under Pillar Two.