Collaborative Research: Communication, Cartels and Collusion

保持企业之间的良性竞争是经济健康发展的关键。卡特尔扼杀这种竞争，导致价格上涨，限制消费者的选择。事实上，反垄断法的目的就是确保这种情况不会发生。最近在美国和欧洲对卡特尔的起诉的案例文件指出，定期和频繁的-有时甚至每周-沟通在维持高价格方面发挥着重要作用。另一方面，经济学理论或多或少对沟通是否会促进共谋保持沉默。在这个项目中，PI建议研究对消费者有害的环境类型和通信类型。例如，公司经常交换销售数据，声称这实际上对经济有利-它使公司能够确定市场状况并改善投资决策。PI的初步研究表明，销售数据的交换也可能是有害的-它允许公司相互监督，看看卡特尔成员是否遵守协议。这表明，如果对这种交流加以限制，比如说，如果销售数据只按年而不是按季度交换，社会将从中受益。这个项目将寻求发展一个更好的理论理解，何时以及如何这样的政策将提高福利。检查沟通在卡特尔中的作用将代表我们对共谋的理解的一个重大的知识进步，以及指导政府和商业政策的一个实际进步。具体来说，这个项目是由两个主要问题驱动的。第一，企业间沟通如何影响竞争？什么样的传播方式对社会有害，什么样的传播方式对社会无害？第二，一般来说，沟通如何促进长期关系中的合作？Awaya和Krishna的工作已经解决了市场需求相当多变的情况下的第一个问题。他们表明，在这种环境下，如果没有任何沟通，企业就无法成功地串通，因为很难发现任何卡特尔协议的偏离。但是，如果企业能够通过交换甚至无法核实的销售数据来进行沟通，那么它们就可以维持高价格和高利润。即使是无法核实的数据也可以被用来促进勾结，这一事实令人惊讶。该项目第一部分的主要目标是探讨这一发现在多大程度上扩展到其他类型的通信-特别是通过法院认为是法律的的行业协会交换汇总数据。该项目的第二部分涉及将这些想法扩展到其他情况。它询问沟通是否促进了一般长期关系中的合作，特别是在私人监控下的一般重复游戏。初步研究表明，情况并非总是如此。该项目将设法查明和分类交流对参与者有积极益处的情况。它将开发出在没有通信的重复博弈中限制均衡收益集的方法。然后，它将试图确定什么形式的通信可以克服这些限制，并进一步，什么形式是最有益的。所解决的问题对反托拉斯政策有直接影响。例如，关于何种公司间交流可能对社会有害的问题，这是一项重要的政策。

Maintaining healthy competition among firms is key to the well-being of the economy. Cartels stifle such competition, leading to higher prices and restricted choices for consumers. Indeed, the purpose of antitrust law is to ensure that this does not happen. Case documents from recent cartel prosecutions in the US and Europe point to the important role that regular and frequent---sometimes even weekly---communication plays in sustaining high prices. Economic theory, on the other hand, is more or less silent on whether or not communication facilitates collusion. In this project, the PIs propose to study both the kinds of environments and the kinds of communication which are harmful to consumers. For instance, firms frequently exchange sales figures claiming that this is actually beneficial to the economy---it allows firms to ascertain market conditions and improve investment decisions. The PIs' preliminary research indicates that the exchange of sales figures can also be detrimental---it allows firms to monitor each other to see if cartel members are complying with the agreement. This suggests that society would benefit if limits were placed on such communication---say, if sales figures were exchanged only yearly rather than quarterly. This project will seek to develop a better theoretical understanding of when and how such a policy would improve welfare.Examining the role of communication in cartels would represent both a significant intellectual advance in our understanding of collusion, and a practical advance in guiding government and business policy.Specifically, this project is driven by two major questions. First, how does inter-firm communication affect competition? What forms of communication are detrimental to society and what forms are not? Second, how does communication facilitate cooperation in long-term relationships in general? Work by Awaya and Krishna has addressed the first question in situations in which market demand is rather variable. They showed that in this environment, absent any communication, firms are not able to successfully collude because detecting departures from any cartel agreement is difficult. But if firms can communicate, by exchanging even unverifiable sales data, then they can sustain high prices and profits. The fact that even unverifiable data can be used to foster collusion is surprising. The main objective of the first part of the project is to explore the extent to which this finding extends to other kinds of communication---in particular, the exchange of aggregate data via trade associations which the courts deem to be legal.The second part of the project concerns the extension of these ideas to other contexts. It asks whether communication facilitates cooperation in general long-term relationships, specifically, general repeated games with private monitoring. Preliminary research indicates that this is not always the case. The project will seek to identify and classify situations in which communication has a positive benefit to the participants. It will develop methods for bounding the set of equilibrium payoffs in repeated games without communication. It will then seek to identify what forms of communication can overcome the bounds and further, what forms are most beneficial.The questions addressed have direct implications for antitrust policy. For instance, it is an important policy as to what kinds of inter-firm communication are potentially detrimental to society.