Since their invention in 2007, green bonds have become a key mechanism by which money is channeled into environmentally beneficial projects.However, questions about what, exactly,is “green”about green bonds remain open.This lack of consensus represents one of the major obstacles to continuing to scale green debt. To explore the challenges of ascertaining and communicating potential environmental benefits, this article explores the range of institutions involved in the origination and distribution of green bonds. It does so by conceiving of the connections between these institutions through the communication of risks, both financial and environmental, as the infrastructure of green bonds. The relative complexity of this infrastructure compared to that of “vanilla” debt, owing to the added nodes of environmental risk, is a core challenge. The article includes a visualization of this infrastructure of risk that demonstrates moments in which risk is originated, combined, partitioned,and held.The paper concludes with brief reflections on the utility of conceiving of the green debt value chain as the infrastructure of paired environmental-financial risk.