Using a novel dataset that combines information on customer-supplier trade relationships with information on firm-bank lending relationships, we show that common banks that lend to firms at both ends of a trade link grow and strengthen such trade relationships. To establish causality, we use bank mergers, which generate exogenous variations in the presence of common banks, and show that common bank relationships between customers and suppliers increase trade relationships by 49.6%. We find that the role of a common bank is greater when it is more informed and when supply chains suffer from larger information and holdup problems. We also document that suppliers with common banks face lower spillover risks from a distressed customer. Overall, our findings show the unique role of banks in driving inter-firm growth and investment by mitigating information and holdup problems, which arguably leads to greater economic growth.

The share of secured debt issued (as a fraction of total corporate debt) declined steadily in the United States over the twentieth century. This stems partly from financial development giving creditors greater confidence that high‐quality borrowers will respect their claims even if creditors do not obtain security upfront. Consequently, such borrowers prefer retaining financial flexibility by not giving security up front. Instead, security is given contingently—when a firm approaches distress. This also explains why, superimposed on the secular decline, the share of secured debt issued is countercyclical.