Collaborative Research: Communication, Cartels and Collusion

保持公司之间的良性竞争是经济福祉的关键。卡特尔扼杀了这种竞争，导致价格上涨，限制了消费者的选择。事实上，反垄断法的目的是确保这种情况不会发生。美国和欧洲最近卡特尔起诉的案件文件表明，定期和频繁的--有时甚至每周--沟通在维持高油价方面发挥着重要作用。另一方面，经济学理论对沟通是否促进串通或多或少保持沉默。在这个项目中，PI建议研究对消费者有害的环境和沟通的种类。例如，公司经常交换销售数据，声称这实际上对经济有利-它允许公司确定市场状况，改善投资决策。PIS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了协议。这表明，如果限制这种交流，社会将受益-比方说，如果销售数据只按年交换，而不是按季度交换。这个项目将寻求在理论上更好地理解这种政策何时以及如何改善福利。研究卡特尔中沟通的作用将代表着我们在理解串通方面的重大智力进步，以及在指导政府和商业政策方面的实际进步。具体地说，这个项目由两个主要问题驱动。首先，企业间沟通如何影响竞争？哪些传播形式对社会有害，哪些传播形式不有害？第二，交流如何促进长期关系中的合作？Awaya和Krishna的工作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，在没有任何沟通的情况下，公司无法成功串通，因为很难检测到违反任何卡特尔协议的情况。但如果公司能够沟通，甚至通过交换无法核实的销售数据，那么他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助长串通，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结论在多大程度上适用于其他类型的通信-特别是通过法院认为合法的行业协会交换汇总数据。它询问通信是否促进了一般长期关系中的合作，特别是在私人监督下的一般重复游戏。初步研究表明，情况并不总是如此。该项目将设法查明通信对参与者有积极益处的情况并对其进行分类。它将开发出在没有沟通的情况下，在重复博弈中限制均衡收益集的方法。然后，它将寻求确定哪些形式的通信可以克服限制，并进一步确定哪些形式最有益。所解决的问题对反垄断政策有直接影响。例如，什么类型的公司间沟通可能对社会有害，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.