For many reasons, examined in this book, the OECD’s Pillar One would not provide for the effective taxation of highly digitalized platform firms, and, by extension, it would not stabilize the international tax system. The author argues that source-based taxation and the arm’s length standard are entirely compatible with the attribution of a portion of highly digitalized platform firms’ taxable income to market jurisdictions. However, new transfer pricing methodologies and a revised definition of ‘control’ for transfer pricing purposes are required to achieve this result.