We introduce a new approach to showing existence of equilibrium in models of economies with unbounded short sales. Inspired by the pioneering works of Hart (1974) on asset market models, Grandmont (1977) on temporary economic equilibrium, and of Werner (1987) on general equilibrium exchange...

This paper analyzes how insurance companies allow the issue of market incompleteness to be overcome. A general equilibrium economy is considered in which heterogeneous agents face endowment risks. Markets are incomplete: there are only markets for trading commodities ex-post and hedging price...

“Buy Now, Pay Later” (BNPL) and other forms of consumer credit create a wedge between consumption and payments. We introduce this wedge into a standard consumption-based asset pricing model (CCAPM). In equilibrium, the pricing kernel equals the marginal utility of consumption divided by the...

The classic Arrow-Debreu framework requires a very large number of specific securities to reach Pareto optimality. The present paper shows that financial intermediation can play an important role in maintaining a more parsimonious market framework while still obtaining Pareto optimality. In the...

The Lehman Brothers' bankruptcy triggered the failure of the collateralized debt markets, which was a major contributor of the financial crisis in 2008. Such collateralized debt markets have both collateral price channel and counterparty (borrower and lender) channel of contagion. I propose a...

When modelling the aggregate behavior of a population over long periods of time the standard approach is to consider the system as always being in equilibrium -- using averaging procedures based upon assumptions of rationality, utility-maximization and a high degree of independence amongst the...

Two major trends in the world economy are international migration and environmental degradation. The object of the paper is to analyze the connection between these two trends, which have generally been analyzed in isolation. Here we represent a world economy in which the exploitation of natural...

Recruiting agents, or "programs" costly screen “applicants” in matching processes, and congestion in a market increases with the number of applicants to be screened. To combat this externality that applicants impose on programs, application costs can be used as a Pigouvian tax. Higher costs...

I demonstrate a straightforward but apparently widely unrecognized implication of the standard requirements for perfect competition: an economy in which consumers can choose to learn is generally not perfectly competitive. In particular, if endogenous welfare relevant learning is feasible, the...

In this paper, we consider economies with (possibly endogenous) solvency constraints under uncertainty. Constrained ine±ciency corresponds to a feasible redistribution yielding a welfare improvement beginning from ev- ery contingency reached by the economy. A sort of Cass Criterion (Cass [10])...