Yiquan Gu

Price-dependent demand in spatial models

Abstract This paper introduces price-dependent individual demand into the circular city model of product differentiation. We show that for any finite number of firms, an unique symmetric price equilibrium exists provided that demand functions are not “too” convex. As in the case of unit demand, the number of firms under free entry decreases in the fixed cost of entry while increases in the transportation cost of consumers. However, this number is no longer always in excess of the socially optimal level. Insufficient entry occurs when the fixed and transportation costs are high.

Strategic Obfuscation and Consumer Protection Policy

This paper studies obfuscation decisions by firms. We show that more prominent firms are more likely to obfuscate. While prominent firms always choose maximum obfuscation, the obfuscation by less prominent firms depends on the degree of asymmetry in prominence and consumer protection policy. We evaluate the impact of a consumer protection policy that limits the scope of obfuscation. We show that such a policy may not be effective as less prominent firms may increase their obfuscation practice.

A Note on the Excess Entry Theorem in Spatial Models with Elastic Demand

This paper revisits the excess entry theorem in spatial models a la Vickrey (1964) and Salop (1979) while relaxing the assumption of inelastic demand. Using a demand function with a constant demand elasticity, we show that the number of firms that enter a market decreases with the degree of demand elasticity.We find that the excess entry theorem does only hold when demand is sufficiently inelastic. Otherwise, there is insufficient entry. In the limiting case of unit elastic demand, the market is monopolized. We point out when and how a public policy can be desirable and broaden our results with a more general transportation cost function.

Product Variety, Price Elasticity of Demand and Fixed Cost in Spatial Models

This paper explores the implications of price-dependent demand in spatial models of product differentiation. We introduce consumers with a quasi-linear utility function in the framework of the Salop (1979) model. We show that the so-called excess entry theorem relies critically on the assumption of completely inelastic demand. Our model is able to produce excessive, insufficient, or optimal product variety. A proof for the existence and uniqueness of symmetric equilibrium when price elasticity of demand is increasing in price is also provided.

The Inefficiency of Market Transparency – A Model with Endogenous Entry

Including the entry decision in a Bertrand model with imperfectly informed consumers, we introduce a trade-off at the level of social welfare. On the one hand, market transparency is beneficial when the number of firms is exogenously given. On the other, a higher degree of market transparency implies lower profits and hence makes it less attractive to enter the market in the first place. It turns out that the second effect dominates: too much market transparency has a detrimental effect on consumer surplus and on social welfare.

Consumer confusion, obfuscation and price regulation

This paper studies firms’ obfuscation choices in a duopoly setting where two firms differ in their marginal costs of production. We show that the high-cost firm chooses maximum obfuscation while the lowcost firmchooses minimal (maximal) obfuscation if the cost advantage is large (small). We argue that price regulation might be a useful policy in such an environment for two reasons: Introducing a price cap benefits consumers as it i) makes pricing more competitive and ii) reduces firms’ incentives to obfuscate. Moreover, a price cap benefits social welfare as it shifts production to the more efficient low-cost firm.

Too much of a good thing? Welfare consequences of market transparency

This paper studies welfare consequences of consumer-side market transparency with endogenous entry of firms. Different from most studies, we consider the unique symmetric entry equilibrium, which is in mixed strategies. We identify two effects of market transparency on welfare: a competition effect and a novel market-structure effect. We show, surprisingly, that for almost all demand functions the negative market-structure effect eventually dominates the positive competition effect as the market becomes increasingly transparent. Consumer-side market transparency can therefore be socially excessive even without collusion. The only exception among commonly used demand functions is the set of constant demand functions.