We develop a perturbational technique to approximate equilibria of a wide class of discrete-time dynamic stochastic general equilibrium heterogeneous-agent models with complex state spaces, including multi-dimensional distributions of endogenous variables. We show that approximating policy...

We study optimal tax policy in a dynamic private information economy with endogenous private markets. We characterize efficient allocations and competitive equilibria. A standard assumption in the literature is that trades are observable by all agents. We show that in such an environment the...

The paper analyzes an implementation of an optimal disability insurance system as a competitive equilibrium with taxes. The problem is modeled as a dynamic mechanism design problem in which disability is unobservable. We show that an asset-tested disability system in which a disability transfer...

In this paper, we generalize the notion of Pareto-efficiency to make it applicable to environments with endogenous populations. Two efficiency concepts are proposed, P-efficiency and A-efficiency. The two concepts differ in how they treat people who are not born. We show how these concepts...

This paper develops a model of a monetary economy in which individual firms are subject to idiosyncratic productivity shocks as well as general inflation. Sellers can change price only by incurring a real menu cost.' We calibrate this cost and the variance and autocorrelation of the...

In this chapter we study dynamic incentive models in which risk sharing is endogenously limited by the presence of informational or enforcement frictions. We comprehensively overview one of the most important tools for the analysis such problems -- the theory of recursive contracts. Recursive...

We study optimal fiscal and redistributive policies in an open economy without commitment. Due to its redistributive motives, the government's incentive to default on its external debt is affected by inequality. We show that in equilibrium the economy endogenously fluctuates between two regimes....

We propose a new business cycle theory. Firms need to randomize over firing or keeping workers who have performed poorly in the past, in order to give them an ex-ante incentive to exert effort. Firms have an incentive to coordinate the outcome of their randomizations, as coordination allows them...

This paper studies growth and structural transformation of the Chinese economy from 1953 to 2012 through a lens of a two-sector growth model. The main goal of the paper is to provide a systematic analysis of both the pre-1978 reform and post-1978 reform periods in a unified framework. First, we...

We develop a general method to study the effects of non-linear taxation in dynamic settings using variational arguments. We first derive general theoretical formulas that characterize the welfare effects of local tax reforms and, in particular, the optimal tax system, potentially restricted...