The method used to calculate the 15% minimum effective corporate tax rate under BEPS Pillar 2 is being called into question in the US because of the knock-on effects of using financial accounting in the tax base. The concerns, raised by a group of US academics as the Biden administration attempts to bring US domestic law in line with BEPS rules, underscores the challenging environment lying ahead for the BEPS project that, last month, locked Ireland in as one of the world’s lowest corporation tax jurisdictions.