The OECD/G20 Base Erosion and Profit Shifting (BEPS) Project deliverables include, among other recommendations, changes to the OECD Model. In order to fulfil the desire of OECD and G20 leaders to dramatically increase the pace in reforming international tax law, the OECD is introducing with the multilateral instrument an innovative tool which should allow rapid implementation of agreed treaty-related measures. The authors address the origin of and work related to this multilateral instrument, its potential contents and the outstanding issues.