Locally consistent oligopolistic equilibria are Cournot–Walras equilibria

A kth-order locally consistent equilibrium is an imperfectly competitive general equilibrium point at which firms only perceive at kth-order Taylor expansion of their true demand curves. It is shown that the set of kth-order locally consistent equilibrium strategies coincides with the set of Cournot–Walras equilibria as soon as k >1, under simple regularity conditions.     

Coalition-proof supply function equilibria in oligopoly

In an industry where firms compete via supply functions, the set of equilibrium outcomes is large. If decreasing supply functions are ruled out, this set is reduced significantly, but remains large. Specifically, the set of prices that can be sustained by supply function equilibria is the interval between the competitive price and the Cournot price. In sharp contrast, when the number of firms is above a threshold we identify (e.g., three if demand is linear), only the Cournot outcome can be sustained by a coalition-proof supply function equilibrium.     

Nonconvexity,efficiency and equilibrium in exhaustible resource depletion

We consider the problem of efficiency and existence of a competitive equilibrium in exhaustible resource markets where extraction costs are nonconvex. Nonconvexity is shown to imply that (1) (efficient) extraction ceases to the left of the minimum efficient scale, i.e., where average costs exceed marginal costs; and (2) a competitive equilibrium does not exist. Introduction of a backstop technology (which induces a flat portion of the industry demand curve) restores both existence and efficiency, provided that the backstop price is sufficiently low. If firms face even a small amount of uncertainty regarding their rivals' stocks, a backstop technology is sufficient to restore existence of competitive equilibrium, even if the backstop price is very high. In this case, however, the competitive equilibrium is not efficient.     

Time inconsistency of benevolent government economies

A dynamic Walrasian economy is said to exhibit inconsistency if the competitive equilibrium path resulting from government reoptimization at some time τ>0 is not a continuation of the competitive equilibrium path resulting from the initial government optimization at time 0. The present paper establishes necessary and sufficient conditions for consistency for a general class of dynamic Walrasian economies. It is seen, for example, that reliance on nondistortionary policy instruments is neither necessary nor sufficient for consistency. It is also shown that Pareto optimal paths can be supported as optimal competitive equilibrium paths only if consistency prevails. However, consistent optimal competitive equilibrium paths need not be Pareto optimal.     

A DYNAMIC ENTRY AND PRICE GAME WITH CAPACITY INDIVISIBILITY

Strategic market interaction is here modelled as a two‐stage game in which potential entrants choose capacities and next active firms compete in prices. Due to capital indivisibility, the capacity choice is made from a finite grid and there are economies of scale. In the simplest version of the model with a single production technique, the equilibrium turns out to depend on the ratio between the level of total output at the long‐run competitive equilibrium and the firm's minimum efficient scale: if that ratio is sufficiently large (the market is sufficiently ‘large’), then the competitive price emerges at a subgame‐perfect equilibrium of the capacity and price game; if not, then the firms randomize in prices on the equilibrium path. The role of the market size for the competitive outcome is shown to be even more important if there are several available production techniques.     

Long run equilibria in an asymmetric oligopoly

Summary. Consider an oligopolistic industry composed of two groups (or populations) of firms, the low cost firms and the high cost firms. The firms produce a homogeneous good. I study the finite population evolutionarily stable strategy defined by Schaffer (1988), and the long run equilibrium in the stochastic evolutionary dynamics based on imitation and experimentation of strategies by firms in each group. I will show the following results. 1) The finite population evolutionarily stable strategy (ESS) output is equal to the competitive (or Walrasian) output in each group of the firms. 2) Under the assumption that the marginal cost is increasing, the ESS state is the long run equilibrium in the stochastic evolutionary dynamics in the limit as the output grid step, which will be defined in the paper, approaches to zero. Received: September 19, 1997; revised: June 18, 1998     

Existence and Uniqueness of Equilibrium in Distorted Dynamic Economies with Capital and Labor

In this paper, we provide a set of sufficient conditions under which recursive competitive equilibrium exists and is unique for a large class of distorted dynamic equilibrium models with capital and elastic labor supply. We develop a lattice based approach to the problem. The class of economies for which we are able to obtain our existence and uniqueness result is considerably larger than those considered in previous work. We conclude by applying the new results to some important examples of monetary economies often used in applied work. Journal of Economic Literature Classification Numbers: C62, D51, D90, E10.     

INCENTIVE EFFICIENT PRICE SYSTEMS IN LARGE INSURANCE ECONOMIES WITH ADVERSE SELECTION

We decentralize incentive efficient allocations in large adverse selection economies by introducing a competitive market for mechanisms, that is, for menus of contracts. Facing a budget constraint, informed individuals purchase (lottery) tickets to enter mechanisms, whereas firms sell tickets and supply slots at mechanisms at given prices. Beyond optimization, market clearing, and rational expectations, an equilibrium requires that firms cannot favorably change, or cut, prices. An equilibrium exists and is incentive efficient. An equilibrium can be computed as the solution to a programming problem that selects the incentive efficient outcome preferred by the highest type within an appropriately defined set. For two‐types economies, this is the only equilibrium outcome.     

OUTPUT CONTINGENT SECURITIES AND EFFICIENT INVESTMENT BY FIRMS

We analyze competitive economies with risky investments. Unlike the classic Arrow–Debreu framing, firms and agents cannot contract upon the exogenous states underlying production risks. They can trade equities and any security written on the endogenous aggregate output. This financial structure is rich enough to promote efficient risk sharing among consumers. However, markets are incomplete from the production perspective, and the absence of prices for each primitive state of nature raises the question about the objective of firms. We show that output‐contingent asset prices convey sufficient information to compute the competitive shareholder value that leads to efficient investment by firms.     

Commodity tax structure under uncertainty in a perfectly competitive market

In a partial equilibrium setting without price uncertainty, the balanced-budget substitution of an ad valorem tax on output for a specific (unit) tax can enhance welfare in imperfectly competitive markets and is without impact in a competitive world. This paper demonstrates that a substitution of this kind can also increase expected output and welfare in a competitive market characterised by uncertainty about the commodity price, if firms can respond to the revelation of demand conditions by altering output.     

Optimum commodity taxation in pooling equilibria

This paper extends the standard model of optimum commodity taxation (Ramsey, F., 1927. A Contribution to the Theory of Taxation. Economic Journal 37, 47–61; Diamond, P., Mirrlees, J., 1971. Optimal Taxation and Public Production, II: "Tax Rules". American Economic Review 61, 261–278) to a competitive economy in which markets are inefficient due to asymmetric information. Insurance markets are prime examples: consumers impose varying costs on suppliers but firms cannot associate costs with individual customers and consequently all are charged equal prices. In such a competitive pooling equilibrium, the price of each good is equal to the average of individual marginal costs weighted by equilibrium quantities. We derive modified Ramsey–Boiteux Conditions for optimum taxes in such an economy and show that, in addition to the standard formula, they include first-order effects which reflect the deviations of prices from marginal costs and the response of equilibrium quantities to the taxes levied. An explanation of the additional terms is provided. It is shown that a condition on the monotonicity of demand elasticities enables to sign the direction of the deviations from the standard case.     

Global asymptotic stability of a competitive equilibrium with recursive preferences

Summary. This paper demonstrates global stability of a competitive equilibrium in a multi-sector model of many firms, each of which exhibits constant returns to scale technology, and of infinitely lived consumers, whose preferences are recursive but not necessarily additively separable. In the topology induced by a sup-norm, the dominant diagonal blocks condition (Araujo and Scheinkman (Econometrica 45, 1977)) allows us to apply the implicit function theorem to obtain continuity of the equilibrium path. If a stationary equilibrium is locally asymptotically stable, then the continuity of the equilibrium path and smoothness of a weight function on heterogeneous consumers imply that all equilibrium paths converge to the steady state. The dominant diagonal blocks condition is also shown to be sufficient for the local asymptotic turnpike property. Received: December 13, 1996; revised version: June 2, 1999     

Equilibrium Wage Dispersion,Firm Size,and Growth

This paper analyzes a model of equilibrium wage dynamics and wage dispersion across firms. It considers a labor market where firms set wages and workers use on-the-job search to look for better paid work. It analyzes a perfect equilibrium where each firm can change its wage paid at any time, and workers use optimal quit strategies. Firms trade off higher wages against a lower quit rate, and large firms (those with more employees) always pay higher wages than small firms. Non-steady-state dispersed price equilibria are also analyzed, which describe how wages vary as each firm and the industry as a whole grow over time. Journal of Economic Literature Classification Numbers: D43, J41.     

Too Much Monitoring, Not Enough Performance Pay

This paper endogenises the internal organisation of competitive firms in a simple general equilibrium framework. The options are monitored teams, unmonitored teams motivated by collective performance pay, and self-employment. The choice of incentive scheme depends on market price and also affects price through its influence on output. As more people opt for self employment, pecuniary externalities increase the pressure on the rest to follow suit and Pareto rankable multiple equilibria arise. The conditions for a competitive equilibrium to be constrained efficient are restrictive and everyone may gain from policies limiting monitoring and self employment and from the imposition of entry taxes.     

Comparative statics in a simple class of strategic market games

This paper investigates the effects of entry in two-sided markets where buyers and sellers act strategically. Applying new tools from supermodular optimization/games, sufficient conditions for different comparative statics results are obtained. While normality of one good is sufficient for the equilibrium price to be increasing in the number of buyers, normality of both goods is required for equilibrium bids and sellers' equilibrium utilities to be increasing in the number of buyers. When the economy is replicated, normality of both goods and gross substitutes guarantee that the equilibrium of the strategic market game converges monotonically (in quantities) to the competitive equilibrium. Simple counter-examples are provided to settle other potential conjectures of interest.     

Competitive behavior in market games: Evidence and theory

We explore whether competitive outcomes arise in an experimental implementation of a market game, introduced by Shubik (1973) [21]. Market games obtain Pareto inferior (strict) Nash equilibria, in which some or possibly all markets are closed. We find that subjects do not coordinate on autarkic Nash equilibria, but favor more efficient Nash equilibria in which all markets are open. As the number of subjects participating in the market game increases, the Nash equilibrium they achieve approximates the associated competitive equilibrium of the underlying economy. Motivated by these findings, we provide a theoretical argument for why evolutionary forces can lead to competitive outcomes in market games.     

Endogenous timing in a mixed oligopoly with semipublic firms

An endogenous order of moves is analyzed in a mixed market where a firm jointly owned by the public sector and private domestic shareholders (a semipublic firm) competes with n private firms. We show that there is an equilibrium in which firms take production decisions simultaneously. This result is strikingly different from that obtained by Pal (Econ Lett 61:181–185, 1998), who shows that when a public firm competes with n private firms all firms producing simultaneously in the same period cannot be sustained as a Subgame Perfect Nash Equilibrium outcome. Our result differs from that of Pal (Econ Lett 61:181–185, 1998) for two reasons: firstly, we consider that there is a semipublic firm rather than a public firm. Secondly, Pal (Econ Lett 61:181–185, 1998) considers that the public firm is less efficient than private firms while in our paper all firms are equally efficient.     

A corporate balance-sheet approach to currency crises

This paper presents a general equilibrium currency crisis model of the ‘third generation’, in which the possibility of currency crises is driven by the interplay between private firms’ credit-constraints and nominal price rigidities. Despite our emphasis on microfoundations, the model remains sufficiently simple that the policy analysis can be conducted graphically. The analysis hinges on four main features (i) ex post deviations from purchasing power parity; (ii) credit constraints a la Bernanke-Gertler; (iii) foreign currency borrowing by domestic firms; (iv) a competitive banking sector lending to firms and holding reserves and a monetary policy conducted either through open market operations or short-term lending facilities. We derive sufficient conditions for the existence of a sunspot equilibrium with currency crises. We show that an interest rate increase intended to support the currency in a crisis may not be effective, but that a relaxation of short-term lending facilities can make this policy effective by attenuating the rise in interest rates relevant to firms.     

Asymmetries in price and quantity adjustments by the competitive firm

Focusing on the crucial role of inventory carry-overs in the production and sales decision, we describe the profit maximizing behavior of a dynamic competitive firm facing random prices. Each firm's behavior is incorporated into a stochastic equilibrium model of the competitive industry with uncertain demand. The industry model exhibits asymmetric cyclical fluctuations of the “Keynesian” sort: when demand is weak, output contracts while price holds at a fixed floor; when demand is strong, price increases as output is constrained by a ceiling. Even in a pure world of constant returns, without increasing costs, the inability to instantaneously coordinate production and sales along with the existence of inventories is sufficient to yield a “backward L” shaped supply curve for the short run.