In February 2024, the OECD published the final version of the Amount B report. This article examines the extended definitive scope of Amount B, also outlining its evolution across the various drafts of the report over time. The article also analyses (i) the main implications of the new guidance included in the report on the transfer pricing methodologies currently in use, focusing in particular on the so-called “pricing matrix”, and (ii) the legal basis chosen for the adoption of Amount B in comparison with that for the remainder of Pillar One.