A comparison of national saving rates in the UK, US and Italy

We develop the approach of Gokhale, Kotlikoff and Sabelhaus [1996. Understanding the postwar decline in US saving: A cohort analysis. Brookings Papers on Economic Activity 0, 315-390], based on the life-cycle model of savings, to decompose the differences in the national saving rates between the UK, US and Italy. Our work suggests that the US saving rate is lower principally because Americans on average retire later. In contrast, the Italian saving rate is higher predominantly because Italians are credit constrained, particularly when young. We also found that demography and the different tax and benefit systems are able to explain little of the cross-sectional differences in saving rates. The study accounts for the possible importance of inter-generational private transfers in determining saving rates.     

Exploitation and time

This paper analyses exploitation and class formation in a dynamic context. An intertemporal model of a subsistence economy is set up and, among other results, it is proved that, in an interior equilibrium, Differential Ownership of (Scarce) Productive Assets is an inherent feature of a capitalist economy, while exploitation tends to disappear in the long run. Asset inequality is therefore proved to be a normatively secondary (though causally primary) wrong. It is also argued that these results raise several doubts about the possibility of providing robust micro-foundations to Marxian concepts by means of Walrasian general equilibrium models.     

Effective property rights, conflict and growth

This paper shows how the interaction between conflict and growth can give rise to a nonmonotone relationship between property rights and social welfare. This interaction is illustrated in a model of endogenous growth in which equilibrium diversion of resources is the cost of securing effective property rights. A symmetric equilibrium allocation associated with more secure property rights and faster growth can be Pareto dominated by one associated with poorer property rights and slower growth. Faster growth can exacerbate the problem of diversion whenever property rights are sufficiently poor. These results call for caution before a society decides to pursue economic growth independently of the institutional structure of property rights. Furthermore, if this structure is inappropriate piecemeal reform might not be in the interest of society, and a substantial reform might be necessary if it is to be welfare-improving.     

Mixed bundling auctions

We study multi-object auctions where agents have private and additive valuations for heterogeneous objects. We focus on the revenue properties of a class of dominant strategy mechanisms where a weight is assigned to each partition of objects. The weights influence the probability with which partitions are chosen in the mechanism. This class contains efficient auctions, pure bundling auctions, mixed bundling auctions, auctions with reserve prices and auctions with pre-packaged bundles. For any number of objects and bidders, both the pure bundling auction and separate, efficient auctions for the single objects are revenue-inferior to an auction that involves mixed bundling.     

Ambiguous events and maxmin expected utility

We study the properties associated to various definitions of ambiguity [L.G. Epstein, J. Zhang, Subjective probabilities on subjectively unambiguous events, Econometrica 69 (2001) 265-306; P. Ghirardato et al., Differentiating ambiguity and ambiguity attitude, J. Econ. Theory 118 (2004) 133-173; K. Nehring, Capacities and probabilistic beliefs: a precarious coexistence, Math. Soc. Sci. 38 (1999) 197-213; J. Zhang, Subjective, ambiguity, expected utility and Choquet expected utility, Econ. Theory 20 (2002) 159-181] in the context of Maximin Expected Utility (MEU). We show that each definition of unambiguous events produces certain restrictions on the set of priors, and completely characterize each definition in terms of the properties it imposes on the MEU functional. We apply our results to two open problems. First, in the context of MEU, we show the existence of a fundamental incompatibility between the axiom of “Small unambiguous event continuity” (Epstein and Zhang, 2001) and the notions of unambiguous event due to Zhang (2002) and Epstein and Zhang (2001). Second, we show that, in the context of MEU, the classes of unambiguous events according to either Zhang (2002) or Epstein and Zhang (2001) are always λ-systems. Finally, we reconsider the various definitions in light of our findings, and identify some new objects (Z-filters and EZ-filters) corresponding to properties which, while neglected in the current literature, seem relevant to us.     

Optimal search auctions

We study the design of profit maximizing single unit auctions under the assumption that the seller needs to incur costs to contact prospective bidders and inform them about the auction. With independent bidders’ types and possibly interdependent valuations, the seller's problem can be reduced to a search problem in which the surplus is measured in terms of virtual utilities minus search costs. Compared to the socially efficient mechanism, the optimal mechanism features fewer participants, longer search conditional on the same set of participants, and inefficient sequence of entry.     

Coordination and delay in global games

What is the effect of offering agents an option to delay their choices in a global coordination game? We address this question by considering a canonical binary action global game, and allowing players to delay their irreversible decisions. Those that delay have access to accurate private information at the second stage, but receive lower payoffs. We show that, as noise vanishes, as long as the benefit to taking the risky action early is greater than the benefit of taking the risky action late, the introduction of the option to delay reduces the incidence of coordination failure in equilibrium relative to the standard case where all agents must choose their actions at the same time. We outline the welfare implications of this finding, and probe the robustness of our results from a variety of angles.     

The type-agent core for exchange economies with asymmetric information

The type-agent core is a new solution concept for exchange economies with asymmetric information. It coincides with the set of subgame-perfect equilibrium outcomes of a simple competitive screening game. Uninformed intermediaries help the agents to cooperate in an attempt to make some profit. The paper extends the work of Perez-Castrillo [Cooperative outcomes through non-cooperative games, Games Econ. Behav. 7 (1994) 428-440] to exchange economies with non-transferable utility and asymmetric information. The type-agent core is a subset of Wilson's coarse core [Wilson, Information, efficiency, and the core of an economy, Econometrica 46 (1978) 807-816]. It is never empty, even though it may be a strict subset of Wilson's fine core. In addition, it converges towards the set of constrained market equilibria as the economy is replicated.     

The swing voter's curse with adversarial preferences

We analyze voting behavior in a large electorate in which voters have adversarial state-contingent preferences with incomplete information about the state of the world. We show that one type of voter can suffer from the swing voter's curse à la Feddersen and Pesendorfer [The swing voter's curse, Amer. Econ. Rev. 86 (1996) 408-424], and go on to characterize the symmetric Nash equilibria of this model under different parameter values. We prove that unlike settings with nonadversarial preferences, there are equilibria in which in one state of the world, a minority-preferred candidate almost surely wins the election and thus the election may fail to correctly aggregate information. Indeed, we show that the fraction of the electorate dissatisfied with the result can be as large as .     

Wage inequality, technology, and trade

The recent widening of wage inequality has been attributed by some to skill-biased-technical-change and by others to trade liberalization. This paper examines the two explanations within a unified model and also presents a new modeling of skill-biased-technical-change, where skilled workers replace unskilled ones. As a result technology adoption is endogenous and does not occur in all countries. Hence, wages for both types of workers, trade patterns and also factor productivities in all countries are endogenously determined. The model sheds light on the relationship between technology and trade, on the reasons for global productivity differences and on the causes for the recent rise in wage inequality.