Abstract There are three prevailing theories of mortgage default: strategic default (driven by negative equity), cash flow default (driven by negative life events), and double-trigger default (where both negative triggers are necessary). It has been difficult to compare these theories in part because negative life events are measured with error. We address this measurement error using a comparison group of borrowers with no strategic-default motive. Our central finding is that only 6% of underwater defaults are caused exclusively by negative equity, an order of magnitude lower than previously thought. We then analyze the remaining defaults. We find that 70% are driven solely by negative life events (i.e., cash flow defaults), while 24% are driven by the interaction between negative life events and negative equity (i.e., double-trigger defaults). Together, the results provide a full decomposition of the theories underlying borrower default and suggest that negative life events play a central role.

We exploit variation in mortgage modifications to disentangle the impact of reducing long-term obligations with no change in short-term payments (“wealth”), and reducing short-term payments with no change in long-term obligations (“liquidity”). Using regression discontinuity and difference-in-differences research designs with administrative data measuring default and consumption, we find that principal reductions that increase wealth without affecting liquidity have no effect, while maturity extensions that increase only liquidity have large effects. This suggests that liquidity drives default and consumption decisions for borrowers in our sample and that distressed debt restructurings can be redesigned with substantial gains to borrowers, lenders, and taxpayers. (JEL E21, G21, G51, R38)

Using de-identified bank account data, we show that spending drops sharply at the large and predictable decrease in income arising from the exhaustion of unemployment insurance (UI) benefits. We use the high-frequency response to a predictable income decline as a new test to distinguish between alternative consumption models. The sensitivity of spending to income we document is inconsistent with rational models of liquidity-constrained households, but is consistent with behavioral models with present-biased or myopic households. Depressed spending after exhaustion also implies that the consumption-smoothing gains from extending UI benefits are four times larger than from raising UI benefit levels. (JEL D14, D91, E21, E24, E70, J65)

We show that the largest increase in unemployment benefits in US history had large spending impacts and small job-finding impacts. This finding has three implications. First, increased benefits were important for explaining aggregate spending dynamics—but not employment dynamics—during the pandemic. Second, benefit expansions allow us to study the MPC of normally low-liquidity households in a high-liquidity state. These households still have high MPCs. This suggests a role for permanent behavioral characteristics, rather than just current liquidity, in driving spending behavior. Third, the mechanisms driving our results imply that temporary benefit supplements are a promising countercyclical tool. (JEL E21, E24, E32, E62, E71, G51, J65)