Delegated Monitoring and Bank Structure in a Finite Economy

When banks act as delegated monitors of borrowing firms in a finite economy, two factors help banks dominate direct lending: portfolio diversification, which increases with bank size, and bank capitalization, which diminishes with size. With free entry into banking, intermediated equilibria are possible even when direct lending cannot overcome autarky. There are usually multiple intermediated equilibria; these may not be Pareto-ranked by bank size, since smaller banks are better captialized and may Pareto-dominate larger banks. Even when one large bank would be most efficient, assigning a monopoly bank charter to coordinate beliefs on the single bank equilibrium may be unattractive: in some cases, a monopoly bank cannot overcome autarky even though free-entry banking can, and in other cases, the monopoly bank reduces production from the direct lending level. Journal of Economic Literature Classification Numbers: G21, L13, O16.