A Positive Model of Overlapping Income Taxation in a Federation of States

This paper develops a positive theory of overlapping income taxation in a federation of states. Its main motivation comes from the observation that in the U.S. states income tax rates are significantly lower than the federal income tax rate. The analysis shows that in a federal system total productivity dispersion between the states determines the federal tax rate. In fact, there exists a positive relation between the level of productivity dispersion and the federal tax rate, even if the income of the decisive voter is above the mean income. When the individuals’ income is endogenous, the higher the implemented federal tax rate is, the lower the resulting state tax rate will be, even if the decisive voter at the state level has zero pre-tax income. Empirical evidence obtained from a panel data set on tax schedules at the state level supports the main hypothesis of the paper. Most notably, the data points to the existence of a significant trade-off between the states tax rates and the federal tax rate, explained through productivity dispersion