We study optimal redistribution and insurance in a life-cycle economy with private idiosyncratic shocks. We characterize Pareto optima, show the forces determining optimal labor distortions, and derive closed form expressions for their limiting behavior. The labor distortions for high-productivity shocks are determined by the labor elasticity and the higher moments of the shock process; the labor distortions for low-productivity shocks are determined by the autocorrelation of the shock process, redistributive objectives, and past distortions. In a model calibrated using newly available estimates of idiosyncratic shocks, the labor distortions are U-shaped and the savings distortions generally increase in current earnings.(JEL D82, D91, H21, H23, I38, J22, J24)We study a life-cycle economy with individuals who are ex ante heterogeneous in their abilities and experience idiosyncratic shocks to their skills over time. We derive a novel decomposition that allows us to isolate key economic forces determining the optimal labor distortions in life-cycle economies with unobservable idiosyncratic shocks and to provide their characterization. We also compute the optimal labor and savings distortions in a model calibrated to match moments of the labor earnings process from a newly available high-quality US administrative data. The data allow us to estimate the higher moments of the stochastic process for skills, such as kurtosis, which emerge from our analysis as key parameters determining the properties of the optimum.Most of our analysis focuses on characterizing the properties of the optimal labor distortions, or wedges, between marginal utilities of consumption and leisure. We show that the labor distortion in a given period is driven by two components: an intratemporal component that provides insurance against new shocks in that period, and an intertemporal component that relaxes incentive constraints and reduces the

We analytically and quantitatively examine a prominent justi…cation for capital income taxation: goods preferred by those with high ability ought to be taxed. We study an environment where commodity taxes are allowed to be nonlinear functions of income and consumption and …nd that, when ability is positively related to a preference for a good, optimal marginal commodity taxes on this good may be regressive: i.e., declining with income. We derive an analytical expression for optimal commodity taxation, allowing us to study the forces for and against regressivity. We then parameterize the model to evidence on the relationship between skills and preferences and examine the quantitative case for taxes on future consumption (saving). The relationship between skill and time preference delivers quantitatively small, generally regressive capital income taxes and would justify only a fraction of the prevailing level of capital income taxation.

We study optimal labor and savings distortions in a lifecycle model with idiosyncratic shocks. We show a tight connection between its recursive formulation and a static Mirrlees model with two goods, which allows us to derive elasticity-based expressions for the dynamic optimal distortions. We derive a generalization of a savings distortion for non-separable preferences and show that, under certain conditions, the labor wedge tends to zero for sufficiently high skills. We estimate skill distributions using individual data on the U.S. taxes and labor incomes. Computed optimal distortions decrease for sufficiently high incomes and increase with age.

We examine a prominent justification for capital income taxation: goods preferred by those with high ability ought to be taxed. In an environment where commodity taxes are allowed to be nonlinear functions of income and consumption, we derive an analytical expression that reveals the forces determining optimal commodity taxation. We then calibrate the model to evidence on the relationship between skills and preferences and extensively examine the quantitative case for taxes on future consumption (saving). In our baseline case of a unit intertemporal elasticity, optimal capital income tax rates are 2% on average and 4.5% on high earners. We find that the intertemporal elasticity of substitution has a substantial effect on optimal capital taxation. If the intertemporal elasticity is one-third, optimal capital income tax rates rise to 15% on average and 23% on high earners; if the intertemporal elasticity is two, optimal rates fall to 0.6% on average and 1.6% on high earners. Nevertheless, in all cases that we consider the welfare gains of using optimal capital taxes are small.

We analyze optimal pension systems relying on simple policy instruments in a lifecycle environment which admits endogenous decisions of how much to work as well as when to retire. The optimality in this context means the highest welfare that can be achieved within a restricted set of instruments, while keeping the total cost of the pension system unchanged. The policy instruments we consider are the optimized retirement benefit functions modeled after a stylized version of the current US Social Security.