The OECD’s efforts towards addressing the tax challenges arising from digitalization recently reached a new significant phase of work. Indeed, the three-tier profit allocation mechanism embedded in the Secretariat Proposal for a “Unified Approach” under Pillar One (published in October 2019) represents a remarkable and potentially disruptive step forward in the discussion surrounding the taxation of the digital economy. The aim of this article is to contribute to such discussion by analysing the three-tier profit allocation mechanism, evaluating its potential impacts and highlighting its strengths and weaknesses.