This paper analyzes the optimal income tax treatment of couples. Each couple is modelled as a single rational economic agent supplying labor along two dimensions: primary and secondary earnings. We consider fully general joint income tax systems. Separate taxation is never optimal if social...

This paper explores the optimal income tax treatment of couples. Each couple is modelled as a single agent supplying labor along two dimensions: primary-earner and secondary-earner labor supply. We consider fully general nonlinear income tax schedules which creates a multi-dimensional screening...