This study assesses possible pathways for the CDM transition under Article 6 of the Paris Agreement, describing their practical implications and impacts on the global CDM portfolio and its potential eligibility under the Paris Agreement. The authors present the elements for the transition currently under negotiation and identify four pathways for the CDM transition, testing different levels of stringency for the transition criteria. It is necessary to avoid that of billions of CERs become eligible under Article 6 mechanisms, while at the same time encouraging CDM activity developers to continue their mitigation efforts. The study also assesses administrative requirements, transition procedures for CDM activities and how these could affect investments.