Informal finance: A theory of moneylenders

I present a model that analyzes the coexistence of formal and informal finance in underdeveloped credit markets. Formal banks have access to unlimited funds but are unable to control the use of credit. Informal lenders can prevent non-diligent behavior but often lack the needed capital. The theory implies that formal and informal credit can be either complements or substitutes. The model also explains why weak legal institutions increase the prevalence of informal finance in some markets and reduce it in others, why financial market segmentation persists, and why informal interest rates can be highly variable within the same sub-economy.