Commissioned by the Swedish Energy Agency, Perspectives and Zurich University of Applied Sciences (ZHAW) studied the volume and origin of Certified Emissions Reductions (CERs) that are still on the market, looking into information in the various national registries and the Clean Development Mechanism (CDM) registry. The study also draws lessons from the Kyoto Protocol on supply and demand in international carbon markets, as well as transparency and accounting (or the lack thereof). This analysis complements earlier studies on which CDM activities are still active and the potential additional supply of CERs in the instance of a renewed carbon price signal.