A Model of economic mobility and the distribution of wealth

This paper introduces new techniques to obtain a closed-form rank-by-rank characterization of the equilibrium distribution of wealth in a model in which finitely lived households face uninsurable idiosyncratic investment risk. A central result is that the extent of inequality is determined entirely by two factors. The first factor, household exposure to idiosyncratic investment risk, increases inequality. The second factor, cross-sectional mean reversion of household wealth, decreases inequality. We show that economic mobility is decreasing in inequality and increasing in mean reversion, a result that is consistent with recent empirical observations about the geographic variation in mobility that exists both domestically and internationally. Our approach allows us to examine the implications of increased market completeness in the form of a risk-sharing subgroup of households. We show that a risk-sharing subgroup rises or falls in the equilibrium wealth distribution depending on the level of inequality, and that its presence raises welfare and the rate of wealth accumulation for all households in the economy.