【摘要】 近年来，数字经济成为中国经济增长的重要动能，互联网平台发展与数字反垄断呈现趋严的态势，而传统规制理论不足以为数字经济反垄断政策提供理论支持，数字平台的规制创新面临严峻的挑战。通过分析平台企业价格竞争行为，重新识别数字经济垄断问题，剖析数字平台隐形垄断对社会福利的影响。研究结果证明：(1)当平台企业在两个市场的均衡价格均高于边际成本时，相比于垄断的市场结构，双边市场中竞争性平台企业的价格水平均下降。而当市场间存在交叉补贴时，在受补贴市场中，竞争可能会引起均衡价格上升。(2)垄断性平台企业的市场势力不再满足于勒纳指数的“倒弹性”特征，交叉网络外部性导致双边市场失灵，同时也限制了平台企业运用市场势力进行价格加成的能力。(3)为了达到社会最优价格，政府需要通过产业政策或规制政策抵消平台一边的消费者对另一边创造的外部贡献，将交叉网络外部性内部化，从而弥补消费者进入一个市场的私人动机与社会动机的偏差。(4)平台企业借助买方信息优势，形成对卖方的纵向控制，导致平台隐形垄断。政府需要对平台企业的“买方垄断”行为进行有效监督，激励平台企业与平台内经营者尽可能真实地向消费者展示平台厂商的内部信息。更多还原

【Abstract】 As digital economy has become a crucial driver of economic growth in China, anti-monopoly measures are increasingly stringent. However, traditional theories are insufficient to provide theoretical support for the policies. This poses significant challenges to regulatory innovation in digital platforms. This study reexamines monopoly in the digital economy by analyzing the pricing of platform enterprises and assesses the impact of covert monopoly in digital platforms on social welfare. The research findings demonstrate the following results:(1) When the equilibrium prices set by platform enterprises in both markets are higher than marginal costs, competitive platform enterprises in two-sided markets tend to lower their price compared to monopolistic market structures. However, when cross-subsidies exist between markets, competition may lead to an increase in equilibrium prices in the subsidized market.(2) Monopolistic platform enterprises no longer exhibit the“upward sloping” characteristic of market power as measured by the Lerner Index. Cross-network externalities cause market failures in two-sided markets while also limiting the platform enterprises’ ability to exercise price markups based on market power.(3) To achieve socially optimal prices, the government needs to offset the external contributions made by consumers on one side to the other side through industrial policies or regulatory measures, internalizing cross-network externalities and bridging the gap between consumers’ private motives and social motives.(4) Platform enterprises utilize their buyer-side information advantage to establish vertical control over sellers, leading to covert monopolies in platforms. The government needs to effectively supervise the “buyer-side monopoly” of platform enterprises and incentivize them to transparently disclose internal information about the platform to consumers.更多还原