Perfect competition and optimal product differentiation

This paper considers whether a competitive economy will achieve an optimal allocation when firms produce differentiated products.In the model studied, firms market those products which maximize profit given the demand curves facing them. Markets are assumed to be open only for goods actually traded. Competitive conditions are achieved by replicating the consumer sector. It is shown that market equilibrium may be suboptimal if those products not being produced are highly complementary in consumption. Sufficient conditions on preferences and production sets for the market equilibrium to be optimal are given.     

Optimal collusion under imperfect monitoring in multimarket contact

We investigate optimal collusion in repeated multimarket contact under imperfect public monitoring, where two firms operate in m markets and in each market, each firmʼs decision and public signals are binary. We show that in an optimal pure strategy strongly symmetric perfect public equilibrium, the size of efficiency loss is equal to that in the market with the most tempting deviation under single-market contact. Furthermore, we show a sufficient condition under which the symmetric equilibrium is optimal for joint payoff maximization among any perfect public equilibrium.     

Consumer search markets with costly revisits

This paper characterizes equilibrium outcomes in consumer search markets taking the cost of going back to stores already searched explicitly into account. We show that the optimal sequential search rule under costly revisits is very different from the traditional reservation price rule in that it is non-stationary and not independent of previously sampled prices. We explore the implications of costly revisits on market equilibrium in two celebrated search models. In the Wolinsky model, some consumers search beyond the first firm. In this class of models, costly revisits do make a substantive difference and their impact can be of the same order of magnitude as the initial search cost. In the Stahl oligopoly search model where consumers do not search beyond the first firm, there remains a unique symmetric equilibrium that has firms use pricing strategies that are identical to the perfect recall case.     

Evolution in economic games

This paper examines the conditions under which evolutionary processes ‘select’ equilibrium strategies of agents or firms. Under plausible dynamics, optimal selection takes place provided that economic agents are small relative to the environment — that is, each such agent has a negligible effect on others' payoffs. However, when this assumption is not met, survival need not imply optimality. Examples in the contexts of bargaining, bidding, and market competition are presented.     

INSUFFICIENT ENTRY OF EMPLOYEE‐CONTROLLED FIRMS IN A FREE‐ENTRY OLIGOPOLY

This study is a theoretical examination of whether employee‐controlled firms (ECFs) enter a free‐entry oligopolistic market excessively or insufficiently, from the viewpoint of welfare maximization. The excess entry theorem is well known in oligopoly theory. According to this theorem, a greater number of profit‐maximizing firms enter a free‐entry oligopolistic market than is optimal for welfare maximization. We demonstrate the possibility that insufficient entry arises when ECFs compete in a free‐entry market. In particular, we show that if both the demand and cost functions are convex, insufficient ECF entry necessarily occurs. Our results suggest that competition among firms seeking purposes other than profit might lead to insufficient entry because differences in competing firms’ objectives affect the intensity of market competition.     

Some Implications of Imperfect Competition For Recent Trade Theory*

This paper argues that in a general-equilibrium context, it is not sensible for oligopolistic (and mono-polistically competitive) firms to maximize profit, because the outcome would be sensitive to the choice of the numeraire. the natural objective of these firms would be to maximize the utility of the shareholders if the shareholders are identical. I show that even if each firm takes the representative individual's marginal utility of income as given, the outcome of the utility maximization objective is Pareto optimal, and in equilibrium, each firm equates price with marginal cost.     

Money in the pure consumption loan model

The purpose of this paper is to show how modern techniques of Temporary competitive equilibrium analysis can be applied to models of the “pure consumption loan model” type. One considers Samuelson's simplest model where traders live two periods and where money is the only store of value. It is proved that a temporary equilibrium exists if price expectations are sufficiently independent of current prices. A stationary market equilibrium is shown to exist if there is a set of traders (i) whose total resources are greater when they are young than when they are old, (ii) who are indifferent between present and future consumption. It is proved that this existence theorem still holds if the economy is sufficiently “close” to an economy which has this property. A stationary market equilibrium is shown to be Pareto optimal if all traders hold positive cash balances. It may be inefficient if this condition is not satisfied, for some traders may then be willing to borrow, which they cannot do in this model.     

Moral hazard,Bertrand competition and natural monopoly

In the traditional model of Bertrand price competition among symmetric firms, there is no restriction on the number of firms that are active in equilibrium. A symmetric equilibrium exists with the different firms sharing the market. I show that this does not hold if we preserve the symmetry between firms but introduce moral hazard with a customer-sensitive probability of exposure; competition necessarily results in a natural monopoly with only one active firm. Sequential price announcements and early adoption are some equilibrium selection mechanisms that help to pin down the identity of the natural monopolist. The insights of the basic model are robust to many extensions.     

Monopolistic competition,aggregation of competitive information,and the amount of product differentiation

Consider an industry with a large number of homogeneous firms. Each firm's profits are a function of its own strategy and the strategies the other firms select. Suppose other firms' strategies enter into each firm's profit function only through one or more statistics. For example, average price in the market may parameterize every firm's profit function. We prove that, as a general rule, the industry's firms will in equilibrium follow at most M + 1 distinct strategies, where M is the number of statistics by which competitors' strategies affect each firm's profits.     

Liquidity supply and adverse selection in a pure limit order book market

This paper analyzes adverse selection costs and liquidity supply in a pure open limit order book market. We relax assumptions of the Glosten/Såndas modeling framework regarding marginal zero profit order book equilibrium and the parametric market order size distribution. We show that using average zero profit conditions considerably increases the empirical performance while a nonparametric specification for market order size combined with marginal zero profit conditions does not. A cross sectional analysis corroborates the finding that adverse selection costs are more severe for smaller capitalized stocks. We also find additional support for one of the central hypothesis put forth by the theory of limit order book markets, which states that liquidity supply and adverse selection costs are inversely related. Furthermore, adverse selection cost estimates based on our structural model and those obtained using popular model-free methods are strongly correlated. This indicates the robustness of the theory-based approach.     

Strategic interaction between futures and spot markets

We study an oligopolistic industry where firms are able to sell in a futures market at infinitely many moments prior to the spot market. A kind of Folk-theorem is established: any outcome between perfect competition and Cournot can be sustained in equilibrium. We then find that the Cournot outcome can be sustained by a renegotiation-proof equilibrium. However, this is not true for the competitive outcome. Furthermore, only the monopolistic outcome is renegotiation-proof if firms can buy and sell in the futures market. These results suggest, contrary to existing literature, that the introduction of futures markets may have an anti-competitive effect.     

Corporate profit tax,firm entry with unemployment,and income inequality

In this paper, we provide a general equilibrium analysis of corporate profit tax on income distribution, unemployment, and wage inequality. With firm dynamics in industrial sector, we identify a new channel through which profit tax affects income and wage inequality: profit tax cut will widen not only the wage gap between skilled and unskilled labor, but also exacerbate the wage inequality of unskilled labor among different sectors. The welfare effect of profit tax cut depends on unemployment deepening (labor-distortion effect) and more manufacturing firms enter the market (business-creation effect), eroding the market share of incumbent firms (business-stealing effect).     

Profit sharing as entry deterrence mechanism

In a right-to-manage framework, this paper analyzes the optimal choice of the pay scheme (profit sharing vs. fixed wage) in a unionized duopoly with potential market entry and decentralized bargaining. The paper shows that, depending on the institutional features, both pay systems can arise as equilibria in Nash strategies. Under duopoly with committed bargaining, the fixed wage is the Nash equilibrium; with flexible bargaining, an agreement between the incumbent firm and its union about profit sharing arises as Nash equilibrium, if the union is not too strong. A monopoly with threat of entry reinforces the selection of profit sharing as a deterrent mechanism.     

Endogenous Market Structure and Technology Licensing

This paper analyses the optimal licensing strategy of a licensor firm that competes with potential licensee firms in an industry with endogenous entry. The optimal licensing strategy of the licensor firm is to have zero royalty and positive fixed fees, which is a result that sharply contrasts with the existing literature whereby licensor firms tend to charge positive royalties to their rival licensees. Under the optimal licensing strategy, the licensor firm and the licensee firms are active in the market, but not the non‐licensed firms. This equilibrium market structure is socially desirable if the fixed production cost is not too small.     

Strategic Innovation with Complete and Incomplete Labour Market Contracts

In a model of strategic R&D competition between two firms that negotiate with independent unions we show that: (i) incomplete labour market contracts may Pareto-dominate complete labour market contracts (ii) even when complete contracts Pareto-dominate incomplete contracts, economies can get stuck in the incomplete contract equilibrium. These conclusions provide additional strategic reasons why complete labour market contracts may not be used—even if they were feasible. We propose two testable predictions to discriminate between complete and incomplete contracts: (i) the variance of wages is lower with complete contracts; (ii) the variance of employment is higher under complete contracts.     

Does Poaching Distort Training?

We analyse the efficiency of the labour market outcome in a competitive search equilibrium model with endogenous turnover and endogenous general human capital formation. We show that search frictions do not distort training decisions if firms and their employees are able to coordinate efficiently, for instance, by using long-term contracts. In the absence of efficient coordination devices there is too much turnover and too little investment in general training. Nonetheless, the number of training firms and the amount of training provided are constrained optimal, and training subsidies therefore reduce welfare.     

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.     

Asymmetry, stability and growth in a step-by-step R&D-race

We define a notion of stability of equilibrium in an infinitely repeated step-by-step R&D race. The unique symmetric equilibrium is shown to be unstable, and stable asymmetric equilibria arise, if product market competition is intense, firms are patient, imitation is difficult and innovations are large. Some predictions based on symmetric equilibria, e.g. that less patient firms always invest less in research, or that more intensive competition leads to higher economic growth, are reversed for “realistic” values of the underlying parameters.     

Foreign Direct Investment, Local Content Requirement, and Profit Taxation

We develop a partial equilibrium model of foreign direct investment (FDI) in which identical foreign firms locate themselves in a host country to compete in an oligopolistic market for a non-tradeable commodity. The host country, assumed to be small in the market for FDI, makes use of two instruments, viz., a profit tax and a local content requirement, to compete for FDI in the international market. We assume the existence of unemployment in the host country. The structure of optimal instruments and their relationship to the number, and the relative efficiency levels, of the domestic firms, are established     

Holdup and wage dispersion

This paper provides a search-theoretic model of the labor market, in which large firms hire workers sequentially and wages are bargained with full commitment. The firm's optimal vacancy-posting strategy trades off the fact that a larger size decreases marginal benefits from subsequent jobs, but avoids higher future recruiting costs attributable to the holdup effect. The holdup effect is dominant if the production function is not sufficiently concave, resulting in firm-size wage premium. The equilibrium features wage dispersion both within and between firms. When calibrated to the U.S. data, the extended model accounts for 67%–84% of the observed wage dispersion, among which 13%–27% is attributed to the holdup effect.