Loan insurance, market liquidity, and lending standards

We examine loan insurance when lenders can screen at origination, learn loan quality over time, and can sell loans in secondary markets. Loan insurance reduces lending standards but improves market liquidity. Lenders with worse screening ability insure, which commits them to not exploiting future private information about loan quality and improves the quality of uninsured loans traded. This externality implies insufficient insurance. A regulator achieves constrained efficiency by (i) guaranteeing a minimum price of uninsured loans to eliminate a welfare-dominated illiquid equilibrium; and (ii) subsidizing loan insurance in the liquid equilibrium. Our results can inform the design of government-sponsored mortgage guarantees.