We test whether lenders’ screening incentives weaken when faced with the possibility of loan sales. We adopt a new measure of lending standards, the processing time for mortgage applications at the loan level, and use the collapse of the nonagency mortgage-backed securities issuance market as a natural experiment. Secondary market liquidity for nonconforming loans decreased significantly at the end of 2007, but the market for securitizing conforming loans did not experience the same breakdown. Following this event, lenders spent significantly more time screening applications for loans larger than the conforming loan limits than for those below the limits. The processing-time gap widened more for banks with lower capital, greater involvement in the originate-to-distribute model, and larger assets.

We consider a macroprudential approach to analyze the optimal lending policy for the central bank, focusing on spillover effects that policy exerts on money markets. Lending against high-quality collateral protects central banks against losses, but can adversely affect liquidity creation in markets since high-quality collateral gets locked up with the central bank rather than circulating in markets. Lending against low-quality collateral creates counterparty risk but can improve liquidity in markets. We illustrate the optimal policy incorporating these trade-offs. Contrary to what is generally accepted, lending against high-quality collateral can have negative effects, whereas it may be optimal to lend against low-quality collateral.