We propose a theory of skill mobility across cities. It predicts the well documented city size--wage premium: the wage distribution in large cities first-order stochastically dominates that in small cities. Yet, because this premium is reflected in higher house prices, this does not necessarily...

We analyze the role of optimal income taxation across different local labor markets. Should labor in large cities be taxed differently than in small cities? We find that a planner who needs to raise revenue and is constrained by free mobility of labor across cities does not choose equal taxes...