In developing countries, informal firms (those that are not registered with the government) account for about half of all economic activity. We consider three broad views of the role of such firms in economic development. According to the romantic view, these firms would become the engine of...

This paper develops and estimates an equilibrium model where heterogeneous firms can exploit two margins of informality: (i) not register their business, the extensive margin; and (ii) hire workers "off the books", the intensive margin. The model encompasses the main competing frameworks for...