The Impact of Social Insurance on Household Debt

This paper investigates how the expansion of social insurance affects households’ accumulation of debt. Insurance can reduce reliance on debt by lessening the financial impact of adverse events such as illness and job loss. But it can also weaken the motive to self-insure through savings, and households’ improved financial resilience can increase access to credit. Using data on 10 million people and a quasi-experimental research design, we estimate the causal effect of expanded insurance on household debt, exploiting ZIP-level heterogeneity in exposure to the staggered expansions of one of the largest US social insurance programs: Medicaid. We find that a 1 percentage point increase in a ZIP code’s Medicaid-eligible population increases credit card borrowing by 0.38%. Decomposing this effect in a model of household borrowing, we show that increased credit supply in response to households’ improved financial resilience drives the rise in borrowing and contributes 30% of the net welfare gains of expanding Medicaid.