The modern literature on city formation and development, for example the New Economic Geography literature, has studied the agglomeration of agents in size or mass. We investigate agglomeration in sorting or by type of worker, that implies agglomeration in size when worker populations differ by...

This paper analyses in a hidden characteristic set-up the design of the optimal price for a firm which is a monopolist at home but competes abroad against foreign firms. As long as diseconomies of scope are not too strong, the optimal price is identified. The price rule depends on the sign of...

We investigate the role of information frictions in migration. We develop novel moment inequalities to estimate worker preferences while allowing for unobserved worker-specific information sets, migration costs, and location-specific amenities and prices. Using data on internal migration in...