The end of the first commitment period of the Kyoto Protocol (2008–2012) marks a turning point in the history of the clean development mechanism (CDM). This junction warrants posing the question: Did the CDM fulfil its initial design objectives and were there any other benefits? This second benefits report on the CDM aims to answer this question. It updates the previous report (2011) adding several new elements on the overall impact of the CDM. It analyses approximately 4,000 registered CDM projects (excluding programmes of activities) according to four topics: sustainable development, technology transfer, finance and regional distribution. It also includes revised estimates of finance and costs for various types of projects, new estimates of savings and revenue due to the use of certified emission reductions (CERs), examines differences between CDM and non-CDM projects and provides opportunities for improvement in the regional distribution of the CDM.