Common Banking across Heterogenous Regions

We describe the existence of a substantial dispersion of interest margins charged by commercial banks among Chinese provinces and find empirically that the main drivers of interest margins are resource costs. We build a parsimonious dynamic stochastic general equilibrium model featuring both banking and production sectors that we calibrate at both the national and provincial levels. Our model can explain a considerable share of the interest margin charged at the provinicial level, and we find evidence that when Chinese banks adopt a technology imposing the same capital share across provinces, their productivity becomes substantially lower. Since the differences in wages in Chinese provinces are substantial, the adoption of a common technology implies an inefficient industrial structure for the banking industry and a substantial cost for the economy. The adoption of a standardized technology also generates a stronger response of the loan rate to productivity shocks, and thus the capability of banks to smooth regional idiosyncratic productivity shocks hitting firms declines substantially.