The present study is a contribution to the linking discussion of emissions trading systems. Between 2012 and 2016, the comparability of monitoring, reporting and verification (MRV) of established emissions trading systems, carbon tax systems and pure monitoring systems was analysed, inter alia based on the California Cap-and-Trade Program, Target Management System / Korea ETS, Shanghai-ETS, Carbon Pricing Mechanism Australia and the European Emissions Trading System. The approaches formulated for evaluating MRV systems are based on the general reporting principles of transparency, consistency, comparability, completeness and accuracy in order to maintain the robustness and integrity of the data in a common market.