Banking concentration and loan-rate markups in a frictional loan market
构建了一个摩擦性贷款模型，研究银行数量如何影响企业家在谈判中的外部选择，从而解释银行集中度与贷款利率加成之间不稳定的关系，并揭示货币政策通过改变外部选择影响贷款市场势力的新渠道。
We present a model of frictional lending where entrepreneurs choose their outside options (self-finance or waiting to find other lenders) when bargaining with banks. When the number of banks is sufficiently small, the equilibrium features self-finance as entrepreneurs’ dominant outside option; when the number of banks is sufficiently large, waiting becomes the dominant outside option. The model can rationalize the mixed empirical evidence on the relationship between banking concentration and loan-rate markups. It also uncovers new policy-dependent channels through which the concentration-markup relationship need not be stable or positive. Depending on the equilibrium regime, monetary policy can alter entrepreneurs’ outside options and change how banking concentration affects loan market power. Our main insight extends to cases with endogenous entry of banks or entrepreneurs, prudential regulation, and default risk.