平台厂商市场势力测度研究——以搜索引擎市场为例

Research on the Market Power Measurement of Platforms——Taking Search Engine as an Example

在双边市场中,交叉网络外部性和非对称定价等特性使得平台厂商的市场份额与市场势力之间的关系变得错综复杂,使用传统市场势力评估方法容易导致误判,而互联网行业中的零边际成本等因素又进一步扩大了二者的差距。基于对勒纳指数核心思想的延伸,本文从平台厂商市场势力的实质入手,构建了一个同时包含市场整体层面和厂商个体层面信息的市场势力衡量指标,从整体角度对平台厂商的市场势力进行衡量,解决了多侧产品、非对称定价等因素对平台厂商市场势力判定的干扰。通过对中国搜索引擎市场的实际检验,本文发现市场份额与市场势力之间具有明显的不对等性,具有最大份额的平台厂商并不具有最强的市场势力,而市场份额很小的平台厂商依然可能具有较强的市场势力。在涉及互联网行业的反垄断执法中,如果过多强调市场份额与市场势力的关系,将有可能忽略实际具有强市场势力的厂商,同时高估大份额厂商的市场势力,由此导致的反垄断执法将不利于市场竞争机制的发挥,也有悖于反垄断的初衷。

The cross-group network externality and asymmetric pricing result in the deviation between the market share and market power of platforms. The traditional evaluating method could be erroneous, and the possibility would be increased further considering the specific features in Internet industries such as zero marginal cost. Based on the core concept of Lerner Index and the essence of platform＇s market power, the paper structures a evaluating index of platform＇s market power with both information of the overall market and the individual platform in two-sided market. The method could eliminate the distraction of multi-products and asymmetric pricing to the evaluation of platform＇s market power. After the theoretical analysis, the paper tested the search engine market in China, and the results show there＇s a clear unequivalence between the market share and market power. The search engine with the biggest market share is not the one with strongest market power, while the one with small market share could possess the great market power. If we focus too much on the relationship between market share and market power in the antitrust concerning the Internet industry, the firm with actual strong market power but small market share could be missed and therefore the market power of the one with big market share could be overestimated. This outcome would do harm to the market competition and violate the original intention of antitrust.