Platform Intermediation in a Market for Differentiated Products

We study a two-sided market where a platform attracts firms selling differentiated products and buyers interested in those products. In the unique subgame perfect equilibrium of the game, the platform fully internalizes the network externalities present in the market and firms and consumers all participate in the platform with probability one. The monopolist intermediary extracts all the economic rents generated in the market, except when firms and consumers can trade outside the platform, in which case consumers retain part of the economic rents. The market allocation is constraint efficient in the sense that the monopoly platform does not introduce distortions over and above those arising from the market power of the differentiated product sellers. An increase in the number of retailers increases the amount of variety in the platform but at the same time increases competition. As a result, the platform lowers the firm fees and raises the consumer charges. In contrast, an increase in the extent of product differentiation raises the value of the platform for the consumers but weakens competition. In this case, the platform raises both the charge to the consumers and the fee for the firms.two-sided markets, network externalities, intermediation, advertising

Trade and Industrial Policy of Transition Economies

Trade reforms in transition economies are analyzed in a model of trade and vertical product differentiation. We first show that trade liberalization in transition economies reduces the local firm’s output and raises the prices of all variants. Second, we find that neither free trade nor the absence of a subsidy are optimal. Third, there exists a rationale for a government commitment to use socially optimal trade and industrial policies to release the domestic firm from low-quality production. Finally, we establish an equivalence result between the effects of exchange rate changes and those of trade policy on price competition (but not on social welfare).Exchange rates, leapfrogging, optimal trade policy, product quality, trade liberalization

Procompetitive Trade Policies

We study the procompetitive effects of trade policies against a foreign oligopoly in a model of vertical product differentiation. We show that a uniform tariff policy like the Most Favored Nation (MFN) clause is always welfare superior to free trade because of a pure rent-extraction effect. However, a nonuniform tariff policy is, in addition, procompetitive and thus yields a higher level of social welfare. The first best policy typically consists of giving a subsidy to the country producing low quality and levying a tariff on the country producing high quality. Regional Trade Agreements (RTYs) are examples of nonuniform tariff policies. We show that these arrangements yield higher welfare than free trade and, moreover, that a RTA with a low-quality producing country yields larger gains than a RTA with a high-quality producing country.endogenous quality, most favored nation (MFN) clause, procompetitive policies, regional trade agreements

Economics: An Emerging Small World?

This paper examines the small world hypothesis. The first part of the paper presents empirical evidence on the evolution of a particular world: the world of journal publishing economists during the period 1970-2000. We find that in the 1970's the world of economics was a collection of islands, with the largest island having about 15% of the population. Two decades later, in the 1990's, the world of economics was much more integrated, with the largest island covering close to half the population. At the same time, the distance between individuals on the largest island had fallen significantly. Thus we believe that economics is an emerging small world. What is it about the network structure that makes the world small? An exploration of the micro aspects of the network yields three findings: one, the average number of co-authors is very small but increasing; two, the distribution of co-authors is very unequal; and three, there exist a number of ‘stars’, individuals who have a large number of co-authors (25 times the average number) most of whom do not write with each other. Thus the economics world is a set of inter-connected stars. We take the view that individuals decide on whether to work alone or with others; this means that individual incentives should help us understand why the economics world has the structure it does. The second part of the paper develops a simple theoretical model of co-authorship. The main finding of the model is that in the presence of productivity differentials and a shortage of high-productivity individuals, inter-connected stars will arise naturally in equilibrium. Falling costs of communication and increasing credit for joint research leads to greater co-authorship and this is consistent with the growth in the size of the giant component.

A Note on Costly Sequential Search and Oligopoly Pricing (new title: Truly Costly Sequential Search and Oligopolistic Pricing,)

We modify the paper of Stahl (1989) on sequential consumer search in an oligopoly context by relaxing the assumption that consumers obtain the first price quotation for free. When all price quotations are costly to obtain, a new equilibrium arises where consumers randomize between not searching at all and searching for one price. The region of parameters for which this equilibrium exists becomes larger as the number of shoppers decreases and/or the number of firms increases. The comparative statics properties of this new equilibrium are interesting. In particular, the expected price increases as search cost decreases, and is constant in the number of shoppers and in the number of firms. We show that the Diamond result never obtains with truly costly search.sequential consumer search, oligopoly, price dispersion

Trade and Industrial Policy of Transition Economies

Trade reforms in transition economies are analyzed in a model of trade and vertical product differentiation. We first show that trade liberalization in transition economies reduces the local firm's output and raises the prices of all variants. Second, we find that neither free trade nor the absence of a subsidy are optimal. Third, there exists a rationale for a government commitment to use socially optimal trade and industrial policies to release the domestic firm from low-quality production. Finally, we establish an equivalence result between the effects of exchange rate changes and those of trade policy on price competition (but not on social welfare)

Procompetitive Trade Policies

We study the procompetitive effects of trade policies against a foreign oligopoly in a model of vertical product differentiation. We show that a uniform tariff policy like the Most Favored Nation (MFN) clause is always welfare superior to free trade because of a pure rent-extraction effect. However, a nonuniform tariff policy is, in addition, procompetitive and thus yields a higher level of social welfare. The first best policy typically consists of giving a subsidy to the country producing low quality and levying a tariff on the country producing high quality. Regional Trade Agreements (RTYs) are examples of nonuniform tariff policies. We show that these arrangements yield higher welfare than free trade and, moreover, that a RTA with a low-quality producing country yields larger gains than a RTA with a high-quality producing country