Securitization and optimal retention under moral hazard

Securitization improves liquidity in capital markets by allowing originators to remove issued loans from its balance sheet and use the proceeds for other purposes. Securitization is often suspected of being one of the main reasons for the recent financial crisis. One concern is that securitization leads to moral hazard in lender screening and monitoring. By selling loans to investors and removing them from their books, banks have a lesser incentive to carefully evaluate and monitor borrowers' credit quality to ensure that they can repay their loans. One problem in the literature is that the analysis of securitization is very general and suffers from a lack of specific security design analysis under asymmetric information. We address the moral hazard problem using a principal-agent model where the investor is the principal and the lender is the agent. We show that the optimal contract must contain a retention clause in the presence of moral hazard. The optimal retention is affected by tranching and credit enhancement.