Spatial quality choice is introduced, where consumers are horizontally differentiated by taste and firms vertically differentiated by quality location, within an equilibrium model of duopoly competition characterized by asymmetric fixed and variable costs. Firms choose quality location followed by prices but then may vertically re-locate their quality offerings based on changing horizontal consumer taste. A monopolistic equilibrium solution arises with firms achieving positive economic profits through price-quality markups exceeding marginal costs. Under strict inequality conditions, each firm acts as a monopolistic competitor within a range of quality choices governed by multiple relative differentiation outcomes. On the other hand, vertical re-location exhibits a resistance to change on the part of vertically located firms such that firms dislike quality re-location and prefer stable preferences in quality. Such resistance to change is overcome by firms re-locating their quality offerings to maximize monopolistic brand-space gains. It is argued that more horizontal differentiation may force more product differentiation by vertical quality relocation. A relative change in quality preferences may result in wider quality spreads in the market through vertical quality re-locations, even though the resistance to change arguments may still hold good.

'This is a high-quality book on an important and central topic in the theory of industrial organisation. It is a cohesive and extremely well written volume which is destined to become a standard work on the subject.' - Mark Casson, University of Reading, UK This original new book offers a comprehensive and engaging perspective on the theory of vertical differentiation. It enables the reader to grasp the key concepts and effects that product quality has both on firms' behaviour and market structure, and the ways in which this relationship has evolved. With contributions from prominent figures in the field, the book investigates a number of important topics, such as the choice of the optimal product range, profit sharing, the existence of equilibrium in duopoly games, positional effects attached to status goods, international trade, collusion, advertising and the dynamics of capital accumulation for quality improvement and product innovation. Using both static and dynamic approaches, these aspects are assessed in relation to the manifold issues of regulation, competition policy and trade policy. Product differentiation and its influence on consumer behaviour and the performance of firms is a core topic in the existing literature in the fields of industrial organization, international trade and economic growth. This book will be an essential read for researchers, students and professional scholars working in these areas, especially those with an interest in antitrust regulation.