Abstract: To get better services, consumers sometimes choose to provide their personal privacy to manufacturers. In this paper, a circle city model was developed, in which consumers decided how much privacy information they were willing to provide to manufacturers while the manufacturers competed for consumer privacy information and derived revenue from consumer purchases and privacy disclosure. It also analyzed the impact of disclosure of consumer privacy on the marketplace, and investigated the impact of optimal market entry on social welfare. The result shows that the market is not fully covered when the consumers’ willingness to pay is low and the differentiation is great. In this case, the optimal pricing of the manufacturers may be negative, and the optimal pricing and maximizing profits of the manufacturers increase but the privacy disclosure decreases with the willingness to pay. The market is fully covered when the consumers’ willingness to pay is low and the differentiation is small, or when the consumers’ willingness to pay is high. In this case, the manufacturers choose not to disclose consumer privacy if the consumers’ willingness to pay is high. Otherwise, the manufacturers derive revenues from both consumer purchase and privacy disclosure. Pricing and profit increase with the increase of differentiation, and decrease with the increase of the number of manufacturer. The optimal market entry analysis shows that the number of manufacturers under the condition of free entry is excessive compared with the number of manufacturers under the maximization of social welfare. However, the level of privacy disclosure with free entry equals that with maximum social welfare. From the perspective of regulation, it means that the provision of consumer information and the disclosure of privacy information can realize the requirement of social optimum if the level of disclosure is informed to consumers.

Key words: Salop model, privacy, market entry

摘要： 为了获得更好的服务,消费者有时选择向厂商提供个人隐私。鉴于此，构建了圆形城市模型，其中，消费者决定自己的隐私提供量，厂商竞争消费者隐私信息，并从消费者的购买和隐私披露中获得利润，分析消费者隐私信息的披露对于市场竞争的影响，考察市场最优进入对于社会福利的影响。研究表明，当消费者支付意愿较低且水平差异化较大时市场不完全覆盖，此时厂商价格可能为负，且厂商的定价和利润都随着支付意愿的增加而增大，隐私披露水平随着支付意愿的提高而降低。当消费者支付意愿较低且水平差异化较小或支付意愿较高时，市场完全覆盖。此时，如果消费者支付意愿较高，则厂商不对消费者隐私进行披露，否则厂商从消费者购买和隐私披露两个方面获得利润，且定价和利润都随着水平差异化的增大而增大，随着厂商数量的增加而减小。厂商市场最优进入分析表明，与社会福利最大化下的厂商数量相比，自由进入的情况下厂商的数量过多。但是，自由进入的隐私披露水平等于社会福利最大化的隐私披露水平。从规制的角度而言，当厂商告知消费者的隐私披露水平时，消费者的隐私提供量和厂商的隐私披露水平能够实现社会福利最大化的要求。

关键词: 模型, 隐私, 市场进入