双寡头电商平台竞争研究:基于纵向产品差异化视角  

Duopoly E-commerce Platforms Competition with Vertical Product Differentiation

作　　者：甄艺凯[1] 崔凯南 ZHEN Yikai;CUI Kainan(China Institute of Regulation Research,Zhejiang University of Finance and Economics/The New Type Key Think Tank of Zhejiang Province"China Research Institute of Regulation and Public Policy";School of Economics,Shandong University)

机构地区：[1]浙江财经大学中国政府监管研究院、浙江省新型重点专业智库“中国政府监管与公共政策研究院”,310018 [2]山东大学经济学院

出　　处：《经济理论与经济管理》2025年第1期151-170,共20页Economic Theory and Business Management

摘　　要：本文在Mussa&Rosen(1978)所提供的质量差异基本分析框架下,构建了电商平台间存在纵向差异(不同平台上的商品质量高低有别)而平台内不同卖家所售的同类产品间存在横向差异(Salop,1979)的双寡头平台竞争模型。在卖家自由进入的市场中,电商平台通过设置第三方卖家费用间接控制平台内卖家的数量,并实现自身利润的最大化。卖家在平台上展开价格竞争。我们将通过一个平台、卖家、消费者三方参与的五阶段动态博弈来展示平台间以及平台内的竞争过程。在均衡结果基础上,容易发现,平台间可替代性增强,会同时导致平台间竞争程度以及平台内竞争程度的增强;而平台内商品之间横向替代性增强反而会导致平台内竞争程度减弱,但最终并不会影响平台间的竞争程度。福利分析表明,无论提升“低质量”还是“高质量”,都将带来消费者总剩余的增加以及社会总福利的提升。但随着“低质量”变高,消费者总剩余增加得更快;而随着“高质量”的增加,社会总福利增加得更快。最后,分析了质量选择内生时的电商平台策略。This paper develops a duopoly e-commerce platforms competition model with vertical product differentiation between platforms and horizontal product differentiation among sellers within the same platform(Salop,1979),based on the framework provided by Mussa&Rosen(1978).The model is specified through a five-stage dynamic game involving two ecommerce platforms,sellers,and consumers.In the first stage of the game,the platforms simultaneously set the access fee for sellers,which would be the only source of profits for platforms;in the second stage,a sufficient number of potential sellers decide whether to enter the platform,with competition ensuring that sellers earn zero expected profit;in the third stage,consumers with different quality preference types choose one of the two platforms as their shopping destination;in the fourth stage,sellers,after evaluating the average intensity of consumer quality preferences on the platform,set the prices of their products;in the final stage,consumers select a seller on the platform that maximizes their net utility from the purchase.Before analyzing platform competition,we first solve for the equilibrium under platform monopoly according to the timing above.There exists a unique pure strategy Perfect Bayesian Equilibrium with symmetric seller pricing for the dynamic game within certain parameter ranges,in both platform monopoly and duopoly.Under the monopoly equilibrium,it can be shown that as product quality rises,the number of brands and the total consumer base on the platform decrease.However,the increase in quality ultimately leads to an improvement in consumer welfare.The key findings regarding platform competition are as follows.(1)An increase in platform substitutability enhances both interplatform and intra-platform competition.However,a rise in horizontal substitutability of products within platforms mitigates intra-platform competition without impacting inter-platform competition.(2)As"high quality"rises,the welfare gains for consumers on the high-quality platform from t

关 键 词：电商平台 平台间竞争 平台内竞争 纵向产品差异 Salop环形城市模型 

分 类 号：F724.6[经济管理—产业经济]