Health insurance plays a major role in mitigating the financial losses of households due to unexpected sickness. However, health insurance coverage is generally suboptimal due to market failures such as information asymmetry. To alleviate this under-insurance problem, many governments have attempted to expand health insurance coverage. Due to the financial burden of expanding health insurance coverage, it is of great interest to both researchers and policymakers to understand the welfare impacts of gaining access to health insurance coverage.Although a direct approach to conducting such welfare analysis is through counterfactual policy simulations using structurally estimated parameters, this approach imposes strong modeling assumptions and is computationally challenging. 1 To overcome these limitations, researchers have used a reduced-form approach combined with subjective well-being (SWB) data to evaluate the welfare impacts of several public policies (Deaton, 2018;Gruber & Mullainathan, 2005;Ludwig et al., 2012;Oishi & Diener, 2014) by presuming that SWB data can proxy for an individual's (experienced) utility (Kahneman & Sugden, 2005).In this study, we attempt to provide causal evidence on the effect of health insurance coverage on SWB by analyzing large-scale healthcare reforms in the United States. Federal and state governments in the United States have implemented several reforms to expand health insurance coverage among the uninsured over the past 2 decades. Many studies have evaluated the effects of these healthcare reforms on outcomes such as health, healthcare utilization, household finances,