In this paper, we propose a new measure of horizontal equity that overcomes many of the shortcomings of previous proposed measures. Our starting point is the observation that a well-behaved social welfare function need not evaluate global' (vertical equity) differences in after-tax income using...

In his influential book, Capital in the 21st Century, Thomas Piketty argues forcefully that rising wealth and wealth inequality is an inherent characteristic of capitalist economies and calls for strong policy responses, in particular a substantial wealth tax implemented globally. This paper...