The importance of consumer multihoming (joint purchases) for market performance: Mergers and entry in media markets

Consumer “multihoming” (watching two TV channels, or buying two news magazines) has surprisingly important effects on market equilibrium and performance in (two‐sided) media markets. We show this by introducing consumer multihoming and advertising finance into the classic circle model of product differentiation. When consumers multihome (attend more than one platform), media platforms can charge only incremental value prices to advertisers. Entry or merger leaves consumer prices unchanged under consumer multihoming, but leaves advertiser prices unchanged under single‐homing: Multihoming flips the side of the market on which platforms compete. In contrast to standard circle results, equilibrium product variety can be insufficient under multihoming.     

Periodic strategies in optimal execution with multiplicative price impact

We study the optimal execution problem with multiplicative price impact in algorithmic trading, when an agent holds an initial position of shares of a financial asset. The interselling decision times are modeled by the arrival times of a Poisson process. The criterion to be optimized consists in maximizing the expected net present value of the gains of the agent, and it is proved that an optimal strategy has a barrier form, depending only on the number of shares left and the level of the asset price.     

Optimal Emissions Taxation under Imperfect Competition in a Durable Good Industry

This paper investigates optimal emissions taxation under imperfect competition in a durable good industry where products are sold (instead of rented). As a benchmark, attention is paid to the special case of monopoly with exogenously given product durability. In line with previous literature, the optimal emission tax in this benchmark model falls short of marginal damage (underinternalization). Extending the benchmark model either to the case of an oligopolistic market structure and/or to the case of endogenous product durability then provides two cases in which the optimal emission tax overinternalizes marginal damage.     

Market microstructure in a global B2B network

On‐line marketplaces raise several interesting issues, among them the relevance of location when content is digitized, and the assessment of a supplier's capabilities when buyers worldwide only have electronic contact with sellers. In global B2B on‐line marketplaces, market microstructures, i.e. which firms compete for the same customers, are thus likely to be influenced by how customers value location and firm capabilities in their decisions to do business with different suppliers on‐line. We suggest that both these sets of attributes will continue to matter on‐line—firms possessing similar capabilities, as well as firms that are similar in location by country, time zones or clusters, will compete for business from the same customers. We model the similarity in competitive positions between pairs of firms based on the overlap in their customer networks, using data on actual interactions between supplier and customer banks on an electronic trading system. Using QAP network regression techniques on the 100 largest banks in this industry, we find that similarity in capabilities influences who competes with whom, and that location still matters in a global B2B exchange. Interestingly, location influences who a firm's competitors are, but not where its customers are from. Copyright © 2001 John Wiley & Sons, Ltd.     

服务业集聚与产业结构优化关系探究

随着全球化进程的不断加快，服务业集聚已经成为人们普遍关注的话题。产业集聚在获得规模效应的同时避免了垄断现象的产生，服务业集聚不但拥有这样的优势，而且还有自己独特的形成和发展特点。从产业结构的优化角度切入，借助区位商和专门化率等分析指标，以江苏省和上海市为例，对服务业集聚的形成进行理论和实证分析，提出产业结构的优化对于服务业集聚的形成和发展有着积极的作用。合理的产业结构能够为服务业集聚提供坚实的基础，各地区应该根据各自的产业特点积极的进行优化，催生服务业集聚，加快本地区经济的进一步发展。     

Designing Optimal Crop Revenue Insurance

When the indemnity schedule is contingent on the farmer's price and individual yield, an optimal crop revenue insurance contract depends only on the farmer's gross revenue. However, this design is not efficient if, as is the case with available contracts, the coverage function is based on imperfect estimators of individual yield and/or price. The producer's degree of prudence and the extent of basis risks have important influences on the optimal indemnity schedule. In this broader context, optimal protection is not provided by available U.S. crop insurance contracts and may include combinations of revenue insurance, yield insurance, futures, and options contracts.     

Tinbergen in De Economist

Jan Tinbergen's scientific writings cover six main areas of research. His articles in De Economist represent these areas; in some cases the contributions to De Economist were of a pioneering nature (business cycles, economic models, economic integration); in others De Economist was the first or even single outlet for Tinbergen's work. This article provides an overview of these contributions. The wide scope of Tinbergen's areas of research goes together with a unity in approach, the characteristics of which are: policy relevance, quantification and measurement, balance in analysis and presentation, and learning from experience. Tinbergen's articles in De Economist bear witness to this approach which at the time also met with scepticism and resistance as this overview shows. According to Houthakker, Tinbergen's main contribution may be that, amidst the pleas of interest groups and the slogans of the laity, an attempt is made that the voice of the professional economic researcher be heard. Tinbergen's work still sets an agenda for both economic research and policy making.     

Discussion and Analysis about Duration Method Based on Marginal Analysis

The selective principle of mutually exclusive project is the maximum of net present value, It is difficult to make decision when NPVA is equal to NPVLB. Some assistant analyses are put forward in ＂Enterprise Investment Decision Management＂. The scientific marginal analysis shows that the assistant analyses including the duration analysis are wrong. This problem can be solved by the classical marginal analysis.     

Generalized piecewise linear histograms

We extend the concept of piecewise linear histogram introduced recently by Beirlant, Berlinet and Györfi. The disadvantage of that histogram is that in many models it takes on negative values with probability close to 1. We show that for a wide set of models, the extended class of estimates contains a bona fide density with probability tending to 1 as the sample size n increases to infinity. The mean integrated absolute error in the extended class of estimators decreases with the same rate n^–2/5 as in the original narrower class.