Does access to free health insurance affect household labor supply decisions? We address this question by exploiting the 2002 introduction of universal health insurance in Mexico (Seguro Popular, SP) that broke the link between access to health care and job contract. Reducedform estimates show that SP increased informality among less educated families with children by 3.5%. We develop and estimate a household search model that incorporates the value of formal sector amenities relative to pre-reform alternatives, and the value of health insurance. Model estimates show that households value SP by, at most, 1.33 per unit of net cost.

We develop an equilibrium wage-posting model with heterogeneous firms that decide to locate in the formal or the informal sector and workers who search randomly on and off the job. We estimate the model on Brazilian labor force survey data. In equilibrium, firms of equal productivity locate in different sectors, a fact observed in the data. Wages are characterized by compensating differentials. We show that tightening enforcement does not increase unemployment and increases wages, total output, and welfare by enabling better allocation of workers to higher productivity jobs and improving competition in the formal labor market.