This paper examines the effects of deposit insurance in a quantitative macroeconomic model that incorporates the risk of deposit runs faced by banks. During systemic panic episodes, alert uninsured depositors tend to withdraw their funds from banks they perceive as vulnerable. While deposit insurance reduces banks’ susceptibility to such runs, it may also weaken their risk management incentives, resulting in a U shaped relationship between insurance coverage and the risk of bank failure. The model suggests that the welfare-maximizing level of deposit insurance coverage for the U.S. in 2008 closely aligns with the observed level. A moderate increase in coverage may be optimal in contexts of heightened depositor alertness—driven by technological or demographic factors—, greater fiscal capacity or stronger capital requirements.