I characterize the optimal linear commodity taxes when households differ in multiple characteristics, in presence of an optimal non-linear tax schedule on the households' labour incomes. The optimal distortions caused by a linear commodity tax are larger if, conditional on labour income, more...

We analyze the optimal nonlinear income tax schedule when taxpayers earn multiple incomes and differ along many unobserved dimensions. We derive the necessary conditions for the government's optimum using both a tax perturbation and a mechanism design approach, and show that both methods produce...