The Department of Economics at the University of Warwick presents the full text of the research paper entitled "Multiproduct Firms and Product Differentiation: A Survey," by Juan A. Manez and Michael Waterson that was published in June 2001. The paper is in PDF format. The authors discuss the impact of horizontal and vertical product differentiation on market structure. Manez and Waterson discuss price elasticity and mark-ups.
This paper analyzes the price-setting behavior of multiproduct firms in a differentiated product market. The structure considered is one where large companies offer either a set of close substitutes (market segmentation) or a set of distant substitutes (market interlacing). The modelling strategy of the paper is to allow for two different elasticities of substitution: the intra-company elasticity of substitution and the inter-company elasticity of substitution. The key feature of the model is the possibility for multiproduct companies to choose their optimal internal organizational structure, according to the relative size of these two parameters. In order to maximize profits, each company may either set prices centrally, or alternatively it may assign an independent product manager to run each division. In other words, product managers of the same company may behave either independently or cooperatively. While the model does not consider either the proliferation or the product-line selection decisions, it deals with multiproduct frms price decisions under oligopolistic competition making use of conjectural variations. Its main purpose has been to provide a micro-founded answer about the question of whether and when a system of independent product managers (decentralized decisions) is better than a mechanism with a centralized general direction. Coordination is always profitable under market segmentation; while under market interlacing, the strategy of relying on independent product managers is profitable when the standard monopolistic competition arises; it may also be profitable with oligopolistic (Bertrand) competition under some assumptions.
There are few industries in modern market economies that do not manufacture differentiated products. This book provides a systematic explanation and analysis of the widespread prevalence of this important category of products. The authors concentrate on models in which product selection is endogenous. In the first four chapters they consider models that try to predict the level of product differentiation that would emerge in situations of market equilibrium. These market equilibria with differentiated products are characterised and then compared with social welfare optima. Particular attention is paid to the distinction between horizontal and vertical differentiation as well as to the related issues of product quality and durability. This book brings together the most important theoretical contributions to these topics in a succinct and coherent manner. One of its major strengths is the way in which it carefully sets out the basic intuition behind the formal results. It will be useful to advanced undergraduate and graduate students taking courses in industrial economics and microeconomic theory.
In this book a rigorous, systematic, mathematical analysis is presented for oligopoly with multi-product firms in static as well as dynamic frameworks in the light of recent developments in theories of games, oligopoly and industrial organization. The general results derived in this book on oligopoly with multi-product firms contain, as special cases, all previous results on oligopoly with single product as well as oligopoly with product differentiation and single product firms. A constructive nu- merical method is given for finding the Cournot-Nash equilibrium, which may be extremely valuable to those who are interested in numerical analysis of the effects of various industrial policies. A sequential adjustment process is also formulated for finding the equilibrium. Dynamic adjustment processes have two versions, one with a discrete time scale and the other with a continuous time scale. The stability of the equilibrium is thoroughly investigated utilizing powerful mathematical results from the stability and linear algebra literature. The methodology developed for analyzing stability proves to be useful for dynamic analysis of economic models.
This paper has two objectives. First, it presents a linear model of monopolistic competition in which weak strategic interactions among single-product firms are allowed for. Second, it extends this model to the case of multiproduct firms, thus showing how product diversity is affected by strong strategic interactions among oligopolists. In our setting, monopolistic competition with single-product firms is a good approximation of oligopolistic competition with multiproduct firms either when varieties are sufficiently differentiated or when scope economies are low.
"In this paper I analyze the productivity gains from trade liberalization in the Belgian textile industry. So far, empirical research has established a strong relationship between opening up to trade and productivity, relying almost entirely on deflated sales to proxy for output in the production function. The latter implies that the resulting productivity estimates still capture price and demand shocks which are most likely to be correlated with the change in the operating environment, which invalidate the evaluation of the welfare implications. In order to get at the true productivity gains I propose a simple methodology to estimate a production function controlling for unobserved prices by introducing an explicit demand system. I combine a unique data set containing matched plant-level and product-level information with detailed product-level quota protection information to recover estimates for productivity as well as parameters of the demand side (markups). I find that when correcting for unobserved prices and demand shocks, the estimated productivity gains from relaxing protection are only half (from 6 to only 3 percent) of those obtained with standard techniques."--abstract.
