Inequality measures and the issue of negative income

Income distribution studies have a long history in economic and statistical literature. Many results in such research area are provided by the standard inequality measure Gini coefficient, traditionally defined for non-negative incomes. In this paper the issue of negative incomes is faced and a specific reformulation of the Gini coefficient is introduced. More precisely, a new Gini coefficient normalization, held by the Pigou-Dalton transfers principle fulfillment, is presented.