DebtStreamness: an ecological approach to credit flows in interfirm networks

Understanding how credit flows through interfirm networks is critical for assessing financial stability and systemic risk. In this study, we introduce DebtStreamness (DS), a metric inspired by trophic levels in ecological food webs, to quantify the position of firms within credit chains. By viewing credit as the primary energy source of the economy, we measure how far credit travels through interfirm relationships before reaching its final borrowers. Applying this framework to Uruguay's interfirm credit and financial institutions-firm networks, using credit registry and survey data from the Central Bank, we find that credit chains are generally short, with a tiered structure in which some firms act as intermediaries, lending to others further along the chain. We also find that local network motifs such as loops can substantially increase a firm's DS, even when its direct borrowing from financial institutions remains the same. Comparing our results with standard economic classifications based on input-output linkages, we find that DS captures distinct financial structures not visible through production data. We further validate our approach using two maximum-entropy network reconstruction methods, demonstrating the robustness of DS in capturing systemic credit structures. These results suggest that DS offers a complementary ecological perspective on systemic credit risk and highlights the role of hidden financial intermediation in firm networks.