Endogenous property rights regimes, common-pool resources and trade

A model is developed where opening to trade affects a dynamic common-pool resource stock and welfare through a community's voting decision to institute a property rights regime regulating the stock. The model finds that resource stock levels can decline even when a Markov perfect equilibrium path for labor and property rights regimes are chosen to maximize welfare. Thus, opening to trade can be welfare maximizing even when resource stock declines. Experimental results show that under certain conditions, subjects briefly follow a Markov perfect equilibrium path for property rights regime choice but labor allocations are myopically chosen indicating that some resource dynamics may be considered by subjects.     

Anonymity and individual risk

Adverse selection economies with private information are generally studied under the assumption that contracts are exclusive. That is, retrading is prohibited. An alternative market mechanism, the anonymous mechanism, is studied here. Risk averse agents trade contingent claims directly and side markets are in equilibrium. The result is the anonymous equilibrium. The anonymous equilibrium results in a set of endogenous transfers and subsidies.     

The dynamics of efficient asset trading with heterogeneous beliefs

This paper analyzes the dynamic properties of portfolios that sustain dynamically complete markets equilibrium when agents have heterogeneous priors. We argue that the conventional wisdom that belief heterogeneity generates continuous trade and significant fluctuations in individual portfolios may be correct but it needs some qualifications. We consider an infinite horizon stochastic endowment economy populated by many Bayesian agents with heterogeneous priors over the stochastic process of the states of nature. Our approach hinges on studying the portfolios that decentralize Pareto optimal allocations. Since these allocations are typically history dependent, we propose a methodology to provide a complete recursive characterization when agents believe that the process of states of nature is i.i.d. but disagree about the probability of the states. We show that even though heterogeneous priors within that class can indeed generate genuine changes in the portfolios of any dynamically complete markets equilibrium, these changes vanish with probability one if the true process consists of i.i.d. draws from a common distribution and the support of some agent's prior belief contains the true distribution. Finally, we provide examples in which asset trading does not vanish because either (i) no agent learns the true conditional probability of the states or (ii) some agent does not know the true process generating the data is i.i.d.     

Privatization and the Political Economy of Strategic Trade Policy

This article considers the interdependence between international financial markets, privatization, and strategic trade policies. We describe an economy where portfolio allocations are chosen by risk-averse agents who rationally forecast future trade policies. Assuming a government responsive to the policy preferences of voters, we show that ownership structure affects trade policy through the incentives for lobbying by private agents. Portfolios and trade policy are thus jointly determined in political-economic equilibrium. Privatization of state-owned industry exerts an important influence over the trade policies chosen by domestic and foreign governments by expanding the scope for individual diversification.     

State prices,liquidity, and default

We show, in a monetary exchange economy, that asset prices in a complete markets general equilibrium are a function of the supply of liquidity by the Central Bank, through its effect on default and interest rates. Two agents trade goods and nominal assets to smooth consumption across periods and future states, in the presence of cash-in-advance financing costs that have effects on real allocations. We show that higher spot interest rates reduce trade and as a result increase state prices. Hence, states of nature with higher interest rates are also states of nature with higher risk-neutral probabilities. This result, which cannot be found in a Lucas-type representative agent model, implies that the yield curve is upward sloping in equilibrium, even when short-term interest rates are fairly stable and the variance of the (macroeconomic) stochastic discount factor is 0. The risk-premium in the term structure is, therefore, a monetary-cost risk premium.     

A coalition proof equilibrium for a private information credit economy

Summary This paper examines an economy in which agents with private information about their own productive capabilities seek to raise capital to fund their investment projects. We employ an equilibrium concept which is closely related to Coalition Proof Nash Equilibrium. In equilibrium, all agents who succeed in raising capital (entrepreneurs) are pooled; they all receive the same contract or consumption schedule. Entrepreneurs, however, are separated from those who fail to raise capital. This separation results in productive efficiency for the economy. If the economy has no viable alternative investment opportunity (other than agents' projects) then equilibrium allocations can be supported by a (non-intermediated) securities market. If there is a viable alternative, the equilibrium allocations cannot be supported by a securities market equilibrium. We interpret this case as suggesting the emergence of financial intermedary coalitions.     

Optimal social security tax with myopic agents

Myopic agents lack the foresight to save for their own old age. It is generally believed that correcting myopia is a rationale for a pay-as-you-go (PAYG) pension system. This view has been supported by existing literature showing that the optimal PAYG social security tax should increase when people are more myopic. In this paper we obtain new results opposed to the traditional view. By establishing a very standard general equilibrium OLG model with myopic agents and endogenized marginal product of capital, we show that the optimal social security tax should be lower when people are more myopic. Our numerical analysis also shows that the welfare cost of the social security tax increases with people's degree of myopia. These results suggest that correcting myopia is not a clear rationale for the PAYG social security.     

Serial dictatorship and Pareto optimality

In a deterministic allocation problem in which each agent is entitled to receive exactly one object, an allocation is Pareto optimal if and only if it is the outcome of a serial dictatorship. We extend the definition of serial dictatorship to settings in which some agents may be entitled to receive more than one object, and study the efficiency and uniqueness properties of the equilibrium allocations. We prove that subgame perfect equilibrium allocations of serial dictatorship games are not necessarily Pareto optimal; and generally not all Pareto optima can be implemented as subgame perfect equilibrium allocations of serial dictatorship games, except in the 2-agent separable preference case. Moreover, serial dictatorship games do not necessarily have unique subgame perfect equilibrium allocations, except in the 2-agent case, hence their outcomes are indeterminate and manipulable.     

Match choice and Ghettoization in evolutionary games

I study how having a choice about who to play affects the conventions that arise in a population playing a 2×2 common interest game. Match choice allows agents playing “fragile but efficient” strategies to isolate themselves, raising their returns but making it harder for outsiders to duplicate their success. When agents are myopic, the second effect dominates: long run play can shift toward either the risk-dominant equilibrium (with common interests in matching) or toward the inefficient equilibrium (with opposing interests in matching). In contrast, when agents are patient, supra-Nash payoffs can be sustained.     

Auctions of Heterogeneous Objects

Simultaneous sealed bid auctions of heterogeneous objects are analyzed. Each bidder's reservation value for an object depends upon the other objects he obtains. Bidders' reservation values are common knowledge. In simultaneous first-price auctions, the set of Walrasian equilibrium allocations contains the set of pure strategy Nash equilibrium allocations which in turn contains the set of strict Walrasian equilibrium allocations. Hence, pure strategy Nash equilibria (when they exist) are efficient. Mixed strategy Nash equilibria may be inefficient. In simultaneous second-price auctions, any efficient allocation can be implemented as a pure strategy Nash equilibrium outcome if a Walrasian equilibrium exists.Journal of Economic LiteratureClassification Numbers: D44, D51.     

Optimal monetary and fiscal policies in a search theoretic model of monetary exchange

Search models of monetary exchange commonly assume that terms of trade in anonymous markets are determined via Nash bargaining, which generally causes monetary equilibrium to be inefficient. Bargaining frictions add to the classical intertemporal distortion present in most monetary models, whereby agents work today to obtain cash that can be used only in future transactions. In this paper, we study the properties of optimal fiscal and monetary policy within the framework of Lagos and Wright (2005). We show that fiscal policy can be implemented to alleviate underproduction while money is still essential. If lump sum monetary transfers are available, a production subsidy can restore the efficiency of monetary equilibria. The Friedman rule belongs to the optimal policy set, but higher inflation rates are also possible. When lump-sum monetary transfers are not available, equilibrium allocations are generally not first-best. Nevertheless, fiscal policy still results in substantial welfare gains. Money can be extracted from circulation via a sales tax on decentralized market activities, and the Friedman rule is only optimal if the buyer has relatively low bargaining power.     

Competitive equilibria with limited enforcement

We show how to decentralize constrained efficient allocations that arise from enforcement constraints between sovereign nations. In a pure exchange economy these allocations can be decentralized with private agents acting competitively and taking as given government default decisions on foreign debt. In an economy with capital these allocations can be decentralized if the government can tax capital income as well as default on foreign debt. The tax on capital income is needed to make private agents internalize a subtle externality. The decisions of the government can arise as an equilibrium of a dynamic game between governments.     

When Borch's Theorem Does Not Apply: Some Key Implications of Market Incompleteness,with Policy Relevance Today

Markets are incomplete when the assets available to the agents do not span the space of future contingencies. In that case, competitive equilibria on the markets for assets and commodities fail (generically) to be constrained efficient. Pareto‐superior allocations can be implemented through price/wage rigidities and quantity constraints. However, nominal rigidities are conducive to multiple equilibria, implying endogenous macroeconomic uncertainties that compound the primitive (exogenous) uncertainties. This paper defines a temporary general equilibrium for which there exists a set of equilibria defining an inflation – unemployment locus. Various policy implications are drawn, with relevance to the current crisis.     

Pension,possible phaseout,and endogenous fertility in general equilibrium

The rich literature on Pay-As-You-Go (PAYG)-type pensions provides a notion that when pension return is dominated by the market return, generally it is impossible to phase pension out without hurting any generation. We show that PAYG pensions can indeed be phased out in a much richer framework where fertility is endogenous and general equilibrium effects are present. Interestingly, the factor that helps us to phase the pension out in a Pareto way is hidden in the structure of PAYG pension itself. Individualistic agents fail to recognize the benefits of their fertility decision on these programs and, therefore, end up in an allocation that is strictly dominated by the allocations that internalize this externality. Exploiting this positive externality, competitive economy can improve its allocations and can reach the planner's steady-state in finite time where each generation secures as much utility as in the competitive equilibrium. Clearly, it is possible to transition in a Pareto way to an economy either with no pension or with pensions whose return is not dominated by market return.     

Functional rational expectations equilibria in market games

The rational expectations equilibrium (REE) has been criticized as an equilibrium concept in market game environments. Such an equilibrium may not exist generically, or it may introduce unrealistic assumptions about an economic agent’s knowledge or computational ability. We define an REE as a probability measure over uncertain states of nature which exploits all available information in a market game, and which exists for almost all economies. Furthermore, if retrading is allowed, it is possible for agents to compute such a ‘functional rational expectations equilibrium’ using straightforward numerical fixed point algorithms. The approach is demonstrated in a detailed numerical example.     

Information-constrained optima with retrading: An externality and its market-based solution

This paper studies the efficiency of competitive equilibria in environments with a moral hazard problem and unobserved states, both with retrading in ex post spot markets. The interaction between private information problems and the possibility of retrade creates an externality, unless preferences have special, restrictive properties. The externality is internalized by allowing agents to contract ex ante on market fundamentals determining the spot price or interest rate, over and above contracting on actions and outputs. Then competitive equilibria are equivalent with the appropriate notion of constrained Pareto optimality. Examples show that it is possible to have multiple market fundamentals or price-islands, created endogenously in equilibrium.     

Risk sharing and retrading in incomplete markets

At a competitive equilibrium of an incomplete-markets economy agents’ marginal valuations for the tradable assets are equalized ex-ante. We characterize the finest partition of the state space conditional on which this equality holds for any economy. This leads naturally to a necessary and sufficient condition on information that would induce agents to retrade, if such information was to become publicly available after the initial round of trade.     

Coordination and discrimination in contracting with externalities: divide and conquer?

The paper studies bilateral contracting between N agents and one principal, whose trade with each agent generates externalities on other agents. It examines the effects of prohibiting the principal from (i) coordinating agents on her preferred equilibrium, and (ii) making different contracts available to different agents. These effects depend on whether an agent is more or less eager to trade when others trade more. The prohibitions reduce the aggregate trade in the former case, and have little or no effect in the latter case. The inefficiencies under different contracting regimes are linked to the sign of the relevant externalities, and are shown to be typically reduced by both prohibitions.     

Optimal asset taxes in financial markets with aggregate uncertainty

This paper studies Pareto-optimal risk-sharing arrangements in a private information economy with aggregate uncertainty and ex ante heterogeneous agents. I show how to implement Pareto optima as equilibria when agents can trade claims to consumption contingent on aggregate shocks in financial markets. The first result is that if aggregate and idiosyncratic shocks are independent, the implementation of optimal allocations does not require any interventions in financial markets. This result can be extended to dynamic settings in the sense that, in this case, only savings need to be distorted, but not trades in financial markets. Second, I characterize optimal trading distortions in financial markets when aggregate and idiosyncratic shocks are not independent. In this case, optimal asset taxes must be higher for those securities that pay out in aggregate states in which consumption is more volatile. For instance, this can provide an efficiency justification for the frequently observed differential tax treatment of different asset classes, such as debt and equity claims.     

Menu theorems for bilateral contracting

This paper studies bilateral contracting where multiple principals negotiate contracts with multiple agents independently. It is shown that pure-strategy equilibrium allocations relative to any ad hoc set of feasible mechanisms are supported by pure-strategy perfect Bayesian equilibria relative to the set of menus. This paper also shows that all equilibrium allocations to any ad hoc set of feasible mechanisms are supported by correlated equilibria relative to the set of menus, where a state is a probability distribution function over payoff-relevant variables. Furthermore, all equilibrium allocations relative to the set of menus persist even if principals use more complex mechanisms.