The paper presents a new theory of trade credit in which firms buy inputs on credit from suppliers to restore the benefits of secured bank financing impaired by contract incompleteness. In a setting where investment is endogenous and unobservable to financiers, we show that a bank-secured credit contract is time-inconsistent. Upon being granted credit, the entrepreneur has an incentive to alter the original input combination, jeopardizing the bank’s revenues. Anticipating the entrepreneur’s opportunism, the bank offers an unsecured credit contract, reducing the surplus from the venture. One way for the entrepreneur to commit to the contract terms is to purchase inputs on credit from the supplier. The supplier observes the input investment and acts as a guarantor that inputs will be purchased as contracted, thus facilitating access to secured bank financing. The commitment role of trade credit still holds in a multi-period extension that investigates the impact of bank relationship lending on secured debt and trade credit. Our model provides novel testable predictions on optimal financial contracts in both one-period and repeated lending relationships.

Assuming that firms’ suppliers are better able to extract value from the liquidation of assets in default and have an information advantage over other creditors, the paper derives six predictions on the use of trade credit. (1) Financially unconstrained firms (with unused bank credit lines) take trade credit to exploit the supplier's liquidation advantage. (2) If inputs purchased on account are sufficiently liquid, the reliance on trade credit does not depend on credit rationing. (3) Firms buying goods make more purchases on account than those buying services, while suppliers of services offer more trade credit than those of standardized goods. (4) Suppliers lend inputs to their customers but not cash. (5) Greater reliance on trade credit is associated with more intensive use of tangible inputs. (6) Better creditor protection decreases both the use of trade credit and input tangibility.