This report provides: an overview of possible options for differentiation in the CDM between different project types and between host countries; a qualitative assessment of the practical feasibility of a number of selected options, with a focus on possible criteria for differentiation and institutional and governance implications; and an assessment of possible impacts on the supply of CDM credits in the carbon market, including the impact on the total supply of credits after 2012 as well as from specific technologies and regions, and possible impacts on carbon prices.