Illegal Immigration and the Shadow Economy

We build a general equilibrium model in which both illegal immigration and the size of the informal sector are endogenously determined and interact in a non-trivial way. We show that policy measures such as tax reduction and detection of informal activities can be used as substitutes for border enforcement, in order to contrast illegal immigration. In our framework, a welfare-maximising Government will never choose to drive illegal immigration to zero, but will set the tax rate to a lower value if it includes illegal immigration in its objective function.