In this communication, we intend to explore the spatial heterogeneity of biodiversity offset policy implementation. While scholars mention the diversity of institutional arrangements across national cases as well as the geographical concentration of biodiversity offsets in some areas more than others, the current literature still fails to provide a strong analysis of the underlying policy processes that explain such heterogeneity. Through the case of biodiversity offset policy implementation under the Endangered Species Act in the USA, we identify two inter-related dimensions that explain the spatial heterogeneity (concentration of 2/3 of conservation banks in California, only 17 other states with conservation banking options). The first one relates to the “regulatory infrastructure” of the US No-Net Loss policy: this notion highlights the idea that among all species listed as endangered, thus theoretically protected through the ESA, only part of them are effectively taken care of at the regional and field level, through dedicated guidelines and templates necessary to translate generic regulations (no-net loss) into practical norms. The investigation reveals how at these levels of policy implementation, local federal offices allocate their time and resources toward some species more than other, based on local expertise, competences and capacity. The second dimension of the analysis relates to the materiality of species. Through the specific case of the American Burying Beetle (ABB), the paper highlights how the physical properties of the species (its biology, its population area) come into play in the implementation process of the mitigation hierarchy. Notably, the size of the population has a direct impact on the economic profitability of conservation banking, which explains why these mitigation tools are only located in Oklahoma, while ABB can be found in six different US states. Analysis of the two dimensions - regulatory infrastructure and ecological materiality - and how they inter-relate can inform ongoing policy debates about the role offsetting can play in strengthening biodiversity governance.