For many kinds of capital, depreciation rates change systematically with the age of the capital. Consider an example that captures essential aspects of human capital, both regarding its accumulation and its depreciation: a worker obtains knowledge in period 0, then uses this knowledge in...

Optimal taxes for Europe and the U.S. are derived in a realistically calibrated model in which agents buy consumption goods and services and use home capital and labor to produce household services. The optimal tax rate on services is substantially lower than the tax rate on goods. Specifically,...

The welfare effects of intergenerational risk sharing through a pay-as-you-go social security system that is efficiently indexed to wages or interest rates are quantified. Comparing steady states, there are large welfare gains of being born into an economy with efficient risk sharing as compared...

We study the impact of tax and transfer programs on steady-state allocations in a model with search frictions, an operative labor supply margin, and incomplete markets. In a benchmark model that has indivisible labor and incomplete markets but no trading frictions we show that the aggregate...