Simon Loertscher

Market Making Oligopoly

This paper analyzes price competition between market makers who set costly capacity constraints before they intermediate between producers and consumers. The unique equilibrium outcome with pure strategies at the capacity stage is the Cournot outcome. The paper thus provides a rationale for Cournot-type competition between market makers. This contrasts with previous findings in the literature, where due to the absence of capacity constraints that are set ex ante the Bertrand result typically obtains.

Market Structure and the Competitive Effects of Vertical Integration

We analyze the competitive effects of backward vertical integration in a model with oligopolistic firms that exert market power upstream and downstream. In contrast to previous literature, we show that a small degree of vertical integration is always procompetitive because efficiency effects dominate foreclosure effects. Moreover, vertical integration even to monopoly can be procompetitive. With regard to market structure, we find, somewhat surprisingly, that vertical integration is more likely to be procompetitive if the industry is more concentrated. Our model thus suggests that antitrust authorities should be particularly wary of vertical integration in relatively competitive industries. We demonstrate that the quantitative welfare effects can be substantial there.

Fee-Setting Mechanisms: On Optimal Pricing by Intermediaries and Indirect Taxation

Mechanisms according to which private intermediaries or governments charge transaction fees or indirect taxes are prevalent in practice. We consider a setup with multiple buyers and sellers and two-sided independent private information about valuations. We show that any weighted average of revenue and social welfare can be maximized through appropriately chosen transaction fees and that in increasingly thin markets such optimal fees converge to linear fees. Moreover, fees decrease with competition (or the weight on welfare) and the elasticity of supply but decrease with the elasticity of demand. Our theoretical predictions fit empirical observations in several industries with intermediaries.

A general non-central hypergeometric distribution

ABSTRACT We construct a general non-central hypergeometric distribution, which models biased sampling without replacement. Our distribution is constructed from the combined order statistics of two samples: one of independent and identically distributed random variables with absolutely continuous distribution F and the other of independent and identically distributed random variables with absolutely continuous distribution G. The distribution depends on F and G only through F○G( − 1) (F composed with the quantile function of G), and the standard hypergeometric distribution and Wallenius’ non-central hypergeometric distribution arise as special cases. We show in efficient economic markets the quantity traded has a general non-central hypergeometric distribution.

Chain Stores, Consumer Mobility, and Market Structure

Homogeneous products are often sold by chains and locals but the chains charge higher prices. We explain this pricing pattern as well as the empirical fact that chains became increasingly dominant at the same time as consumer mobility increased: Consumers bear setup costs whenever they visit a firm for the first time. A chain operating stores in all locations insures consumers against the need to bear setup costs repeatedly when moving to new locations. In equilibrium, the chain charges higher prices and attracts more consumers than locals. As consumer mobility increases, the chains market share and profit increases.

For the Student: Matching and Economic Design

This article presents a brief survey of two‐sided matching. We introduce the reader to the problem of two‐sided matching in the context of the college admission model and explain two central requirements for a matching mechanism: stability and non‐manipulability. We show how the frequently used ‘Boston Mechanism’ fails these key requirements and describe how an alternative, the Deferred Acceptance Algorithm, leads to stable matchings but fails to be non‐manipulable in general. A third mechanism, the Top Trading Cycle, is efficient and non‐manipulable when only one side of the match acts strategically. We also discuss some applications of matching theory.

Biased Experts, Costly Lies, and Binary Decisions

Decision makers lacking crucial specialist know-how often consult with better informed but biased experts. In our model the decision maker’s choice problem is binary and her preferred option depends on the state of the world unknown to her. The expert observes the state and sends a report to the decision maker. His bias is such that he prefers the same decision for all states. Lying about the state leads to a cost that increases in the size of the lie. As a function of the size of the expert’s bias and the decision maker’s prior about the underlying state, three kinds of equilibrium behavior occur. In each case equilibrium consists of separating and pooling segments, and the decision maker takes the expert’s preferred decision for some states for which she would not take this decision had she observed the state herself. The model has a variety of applications and extends to situations in which the decision maker may be naive and take the report by its face value, and to situations with multiple experts and uncertainty about the size of the expert’s bias.