Inequality Is Bad For Income Growth Of the Poor (But Not For That of the Rich):

The average state-level Gini coefficient in the US over the entire 50-year period is 0.43, with a standard deviation of 0.04. Now if a state’s level of inequality were reduced by four Gini points (about one standard deviation of the average) keeping everything else equal, the rate of growth of the very poor (people at the fifth or tenth percentile of income distribution) would increase by 0.9% per capita per annum (pc pa) on average. Since the incomes of the very poor on average grew by 0.8% pc pa, such a reduction in inequality wouldmore than double their growth rate on average. At the other end of the spectrum, the same decrease in inequality would reduce the growth rate of the rich (the top 5%) by 0.3% per capita annually. The rich’s average growth rate over the past half-century was 2% pc pa, so their growth would be cut by about one seventh.

Worth a read.