The transition of CERs issued under the CDM for use by Parties towards their NDCs is a key outstanding issue for Article 6 negotiations at the UNFCCC. To inform the ongoing negotiations, we set out estimates of the potential CER supply by two groups of modelling teams, from research institutes in Japan and Germany. This paper presents an updated analysis of the potential supply of CERs issued for emission reductions occurring in the second commitment period of the Kyoto Protocol between 1 January 2013 and 31 December 2020 based on a selection of possible restrictions for their transition.