平台治理政策对商家绩效的影响——基于某大型电商平台“流量分配优化”改革的准自然实验

The Impact of Platform Governance Policies on Merchant Performance—A Quasi-Experimental Study Based on a Major E-Commerce Platform’s “Traffic Allocation Optimization” Reform

摘要: 近年来，平台经济领域的反垄断与治理政策密集出台，但关于平台治理政策如何影响商家绩效的实证证据仍显不足。本文以2024年某大型电商平台实施的“流量分配优化”政策(取消“二选一”限制、算法推荐向中小商家倾斜)作为准自然实验，采用双重差分法(DID)，基于该平台2019~2025年的商家面板数据，考察治理政策对商家销售绩效的影响。研究发现：1) 政策实施后，受政策影响更大的中小商家的销售额平均提升了18.7%，而头部商家的销售额则出现约6.2%的下降，表明政策起到了“削峰填谷”的再平衡作用；2) 机制检验显示，政策通过提高搜索结果的多样性指数、降低中小商家的流量获取成本以及优化流量分配效率发挥作用；3) 异质性分析表明，拥有较高历史信誉评分(≥4.8)的中小商家受益更为显著，而低信誉商家的提升效果有限，同时店铺年龄较长、位于竞争激烈类目的商家受益更大；4) 进一步分析发现，政策还带来了产品多样性提升和消费者满意度改善等正向溢出效应。本文为理解平台治理的经济后果提供了微观证据，也为政策制定者优化竞争政策提供了参考。

Abstract: In recent years, antitrust and governance policies in the platform economy have been introduced intensively, yet empirical evidence regarding how platform governance policies affect merchant performance remains insufficient. This paper examines the impact of governance policies on merchant sales performance by exploiting a quasi-natural experiment: The “traffic allocation optimization” policy implemented by a large e-commerce platform in 2024, which eliminated “exclusive dealing” restrictions and tilted algorithmic recommendations toward small and medium-sized merchants. Using a Difference-in-Differences (DID) approach and leveraging merchant panel data from 2019 to 2025, we find that: 1) Following the policy implementation, affected small and medium-sized merchants experienced an average sales increase of 18.7%, while top merchants saw a decline of approximately 6.2%, indicating a “peak-clipping and valley-filling” rebalancing effect; 2) Mechanism tests reveal that the policy operates by enhancing search result diversity indices, reducing traffic acquisition costs, and improving traffic allocation efficiency for small and medium-sized merchants; 3) Heterogeneity analysis shows that small and medium-sized merchants with higher historical reputation scores (≥4.8) benefited more significantly, whereas low-reputation merchants exhibited limited improvement; additionally, older stores and merchants in highly competitive categories gained larger benefits; 4) Further analysis demonstrates that the policy also generated positive spillover effects, including enhanced product diversity and improved consumer satisfaction. This study provides micro-level evidence for understanding the economic consequences of platform governance and offers implications for policymakers in optimizing competition policy.