© 2017 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. Negative emissions technologies (NETs), especially bioenergy with carbon capture and storage and direct air capture and storage, have been invoked as necessary to achieve the aspirational 1.5°C target of the Paris Agreement. However, currently their costs are estimated to be very high, NETs do not seem to offer co-benefits besides mitigating climate change and there are significant concerns regarding possible negative impacts of their large-scale implementation on sustainable development. Costs can vary significantly due to locational factors such as availability of biomass resources and geological storage capacity. It will be up to progressive industrialized countries to take first steps to mobilize the mitigation potential of NETs. In order to understand whether NETs can prov ide a significant contribution to mitigation, financial incentives are needed that allow implementing the most attractive NET activities at the global scale. We see the market mechanism under Article 6.4 of the Paris Agreement–colloquially called ‘Sustainable Development Mechanism’–as a possible cornerstone of such a policy instrument. While initially NETs will not be competitive on the free market, the mechanism can facilitate bilateral financial transfers for NETs, where mitigation units accrue to the financier. We discuss the functions and design elements that an international policy instrument may need to fulfil to successfully mobilize NETs. This includes in particular robust quantification of removed carbon under international oversight and preventing social and environmental conflicts particularly on land and water use by NETs to ensure long-term acceptability. Key policy insights International policy instruments that mobilize negative emissions technologies are inexistent despite most mitigation pathways relying on large-scale NETs implementation later this century. Feasibility of NETs at large-scale is highly uncertain due to high expected costs and political economy challenges. Practical experience is necessary for better understanding feasibility. For cost-effective global deployment of NETs, a policy instrument would need to mobilize international financial flows and implement safeguards concerning sustainable development impacts. The sustainable development mechanism established in Article 6.4 of the Paris Agreement could be a good basis for this if it includes a robust approach to evaluating sustainable development impacts building on the sustainable development goals.