We provide evidence on the costs and profitability of relationship lending by banks. We derive bank-specific measures of loan rate smoothing for small business borrowers in response to exogenous shocks to their credit risk and to interest rates, and then estimate cost and profit functions to examine how smoothing affects bank costs and profits. Our results suggests that, in general, loan rate smoothing in response to a credit risk shock is not part of an optimal long-term contract between a bank and its borrower, while loan rate smoothing in response to an interest-rate shock is.

We amend the standard cost model to account for the role of financial capital in banking. The cost function is conditioned on the level of capital, but we model the demand for financial capital so that it can serve as a cushion against insolvency for potentially risk-averse managers and as a signal of risk for less informed outsiders. Scale economies are then computed without assuming that the bank chooses a level of capitalization that minimizes cost. We find evidence of substantial scale economies and that bank managers are risk averse and use the level of financial capital to signal the level of risk.