In this paper, we consider economies with (possibly endogenous) solvency constraints under uncertainty. Constrained inefficiency corresponds to a feasible redistribution yielding a welfare improvement beginning from every contingency reached by the economy. A sort of Cass Criterion (Cass (1972))...

A 'folk theorem' originating, among others, in the work of Stiglitz maintains that competitive equilibria are always or 'generically' inefficient (unless contracts directly specify consumption levels as in Prescott and Townsend, thus bypassing trading in anonymous markets). This paper critically...

We prove indeterminacy of competitive equilibrium in sequential economies, where limited commitment requires the endogenous determination of solvency constraints preventing debt repudiation (Alvarez and Jermann (2000)). In particular, we show that, for any arbitrary value of social welfare in...

Can public insurance through redistributive income taxation improve the allocation of risk in an economy in which private risk sharing is limited? The answer depends crucially on the fundamental friction that limits private risk sharing in the first place. If risk sharing is incomplete because...

This paper develops an analytical framework to study consumption and labour supply in a rich class of heterogeneous-agent economies with partial insurance. The environment allows for trade in non-contingent and state-contingent bonds, for permanent and transitory idiosyncratic productivity...

We develop a method that allows one to compute incomplete-market equilibria routinely for Markovian equilibria (when they exist). The main difficulty to be overcome arises from the set of state variables. There are, of course, exogenous state variables driving the economy but, in an incomplete...

We extend "economic equivalence" results, like the Ricardian equivalence proposition, to the political sphere where policy is chosen sequentially. We derive conditions under which a policy regime (summarizing admissible policy choices in every period) and a state are "politico-economically...

This paper shows how two standard models of consumption risk-sharing - self-insurance through borrowing and saving and limited commitment to insurance contracts - replicate similarly well the standard, second-moment measures of insurance observed in US micro-data. A non-parametric analysis,...

The paper studies the causes of the current financial crisis and considers proposals for mitigation and prevention of future crises. The crisis is was the product of a ‘perfect storm’ bringing together a number of microeconomic and macroeconomic pathologies. Among the microeconomic systemic...

We construct a method to solve models with heterogeneous agents and aggregate uncertainty that is simpler than existing algorithms; the aggregate law of motion is obtained neither by simulation nor by parameterization of the cross-sectional distribution, but by explicitly aggregating the...