This paper examines the effect on the firm's banking cost of the issue of debt securities. We argue over the existence of a positive relationship between the issue of market debt and the reduction of firm's banking cost. This idea relies on three main arguments: i) Banks can delegate to investors the supervision task, a feature that makes bank supervision less costly. ii) The issue of public debt increases firms' bargaining power in front of the banks, as the former can get funds through non-bank financing ch annels. iii) Banks with no prior information on the issuing firm may interpret the issue of debt securities as a positive signal of firm's quality. Additionally, we argue that the previous effects are less important for non-first issue...