Nonconforming Preferences: Jumbo Mortgage Lending and Large Bank Stress Tests

We document a substantial shift toward nonconforming (“jumbo”) mortgage lending by banks subject to Comprehensive Capital Analysis and Review (CCAR) stress tests. Using two measures of this jumbo shift and difference‐in‐difference analysis, we show that jumbos as a share of all mortgage originations by CCAR banks rose and that their originations were less “bunched” just below the conforming loan limit. We explore several potential mechanisms that might explain CCAR banks' increased preference for jumbo with varying degrees of support. Our evidence is most consistent with the hypothesis that CCAR banks were attracted to the relatively lower credit risk of jumbo mortgages.