Efficiency and prices in economies of overlapping generations

In a general economy of overlapping generations, I introduce a notion of uniform ine±ciency, corresponding to the occurrence of a Pareto improvement with a small uniform destruction of resources (Debreu [11]). I provide necessary and su±cient conditions for uniform ine±ciency in terms of competitive equilibrium prices. Minimal assumptions are needed for such a complete characterization; moreover, proofs reduce to simple and short direct arguments. Finally, I verify that uniform ine±ciency is preserved under perturbations of the endowments, a property that has not been established for the canonical notion of ine±ciency. Remarkably, an allocation is unifoOverlapping generations; e±ciency; competitive prices; Cass Criterion; social security

Asset prices, debt constraints and inefficiency

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]) completely characterizes constrained ine±ciency. This criterion involves only observable prices and requires low interest rates in the long-run, exactly as in economies with overlapping generations. In addition, when quantitative limits to liabilities arise from participation constraints, a feasible welfare im- provement, subject to participation, coincides with the introduced notion of constrained ine±ciency.Private debt; solvency constraints; default; Cass Criterion; asset

A Characterization of Inefficiency in Stochastic Overlapping Generations Economies

In this paper, we provide a characterization of interim inefficiency in stochastic economies of overlapping generations under possibly sequentially incomplete markets. With respect to the established body of results in the literature, we remove the hypothesis of two-period horizons, by considering longer, though uniformly bounded, horizons for generations. The characterization exploits a suitably Modified Cass Criterion, grounded on the long-rung behavior of compounded safe interest rates and independent of the length of horizons of generations. Thus, the hypothesis of two-period horizons is purely heuristic in establishing a criterion for inefficiency. In addition, for sequentially incomplete markets, we adopt a suitable notion of unambiguous inefficiency, separating the inefficient intertemporal allocation of resources from incomplete risk-sharing. Unambiguous inefficiency reduces to inefficiency when markets are sequentially complete.

A Note On The Characterization Of Inefficiency In Stochastic Overlapping Generations Economies

In this paper, we provide a characterization of interim ine±ciency in stochastic economies of overlapping generations under possibly sequentially incomplete markets. With respect to the established body of results in the literature, we remove the hypothesis of two-period horizons, by considering longer, though uniformly bounded, horizons for generations. The characteri- zation exploits a suitably Modi¯ed Cass Criterion, grounded on the long-rung behavior of compounded safe interest rates and independent of the length of horizons of generations. Thus, the hypothesis of two-period horizons is purely heuristic in establishing a criterion for ine±ciency. In addition, for sequentially incomplete markets, we adopt a suitable notion of unambiguous ine±ciency, separating the ine±cient intertemporal allocation of resources from incomplete risk-sharing. Unambiguous ine±ciency reduces to ine±ciency when markets are sequentially complete.Stochastic overlapping generations economies; ine±ciency; com-

A characterization of inefficiency in stochastic overlapping generations economies

In this paper, we provide a characterization of interim inefficiency in stochastic economies ofoverlapping generations under possibly sequentially incomplete markets. With respect to the established body of results in the literature, we remove the hypothesis of two-period horizons,by considering longer, though uniformly bounded, horizons for generations. The characterization exploits a suitably Modified Cass Criterion, grounded on the long-run behavior of compounded safe interest rates and independent of the length of horizons of generations. Thus, the hypothesis of two-period horizons is purely heuristic in establishing a criterion for inefficiency. In addition, for sequentially incomplete markets, we adopt a suitable notion of unambiguous inefficiency, separating the inefficient intertemporal allocation of resources from incomplete risk-sharing. Unambiguous inefficiency reduces to inefficiency when markets are sequentially complete.stochastic overlapping generations economies, inefficiency, competitive prices, cass criterion, social security, incomplete markets

Indeterminacy of competitive equilibrium with risk of default

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 [3]). In particular, we show that, for any arbitrary value of social welfare in between autarchy and (constrained) optimality, there exists an equilibrium attaining that value. Our method consists in restoring Welfare Theorems for a weak notion of (constrained) optimality. The latter, inspired by Malinvaud [15], corresponds to the absence of Pareto improving feasible redistributions over nite (though inde nite) horizons.imited commitment; solvency constraints; Malinvaud efficiency Welfare Theorems; indeterminacy; Welfare Theorems; indeterminacy; Welfare Theorems indeterminacy;financial fragility; market collapse

Asset Prices, Debt Constraints and Inefficiency

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 every contingency reached by the economy. A sort of Cass Criterion (Cass [10]) completely characterizes constrained inefficiency. This criterion involves only observable prices and requires low interest rates in the long-run, exactly as in economies with overlapping generations. In addition, when quantitative limits to liabilities arise from participation constraints, a feasible welfare improvement, subject to participation, coincides with the introduced notion of constrained inefficiency.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 every contingency reached by the economy. A sort of Cass Criterion (Cass [10]) completely characterizes constrained inefficiency. This criterion involves only observable prices and requires low interest rates in the long-run, exactly as in economies with overlapping generations. In addition, when quantitative limits to liabilities arise from participation constraints, a feasible welfare improvement, subject to participation, coincides with the introduced notion of constrained inefficiency.Non-Refereed Working Papers / of national relevance onl

Risk and intermediation in a dual financial market economy

We study the competitive equilibria of a simple economy with moral hazard and intermediation costs. Entrepreneurs can simultaneously get credit from two types of competing institutions: ‘financial intermediaries’ and ‘local lenders’. The former are competitive firms issuing deposits and having a comparative advantage in diversifying credit risks. The latter are individuals with a comparative advantage in credit arrangements with a ‘nearby’ entrepreneur. Because of intermediation costs, local lenders are willing to diversify their portfolio by offering some direct lending to nearby entrepreneurs. We show that, in some cases, a fall in intermediation costs, by inducing local lenders to choose a safer portfolio, reduces entrepreneurs’ effort and increases the probability of default. In these cases, taxing intermediaries may be welfare-improving.We study the competitive equilibria of a simple economy with moral hazard and intermediation costs. Entrepreneurs can simultaneously get credit from two types of competing institutions: ‘financial intermediaries’ and ‘local lenders’. The former are competitive firms issuing deposits and having a comparative advantage in diversifying credit risks. The latter are individuals with a comparative advantage in credit arrangements with a ‘nearby’ entrepreneur. Because of intermediation costs, local lenders are willing to diversify their portfolio by offering some direct lending to nearby entrepreneurs. We show that, in some cases, a fall in intermediation costs, by inducing local lenders to choose a safer portfolio, reduces entrepreneurs’ effort and increases the probability of default. In these cases, taxing intermediaries may be welfare-improving.Non-Refereed Working Papers / of national relevance onl

Convex dynamic programming with (bounded) recursive utility

We consider convex dynamic programs with general (bounded) recursive utilities. The Contraction Mapping Theorem fails when the utility aggregator does not obey any discounting property. This failure occurs even with traditional aggregators and certainty equivalent specifications. However, the Bellman operator admits a unique fixed point when an interior policy is feasible. This happens because utility values are unique at interior consumption plans and, when an interior perturbation is feasible, drops in utility values can be avoided