Abstract: In the era of the digital economy，crossborder ecommerce （CBEC），as a new form of international trade，has driven the transformation and upgrading of foreign trade and has become an important lever for the highquality development of Chinas foreign trade However，during CBEC transactions，buyers and sellers often can only communicate through the internet，and factors such as geographical distance，language，and cultural differences constitute significant barriers，leading to severe adverse selection problems Consumer protection policies，as an important platform regulation mechanism，provide a beneficial solution to address adverse selection issues
To comprehensively depict the impact of consumer protection policies on adverse selection problems，this paper utilizes a consumer protection policy implemented by Wish，one of the worlds largest mobile CBEC platforms—the fraudulent fulfillment of orders policy—to conduct a time regression discontinuity analysis，systematically exploring the impact of consumer protection policies on the market entry and exit of products This paper finds that，firstly，the policy significantly reduces the number of new products from enterprises but significantly increases the number of highquality products among them；secondly，the fraudulent fulfillment of orders policy promotes the exit of incumbent products，mainly reflected in the exit of lowquality products The mechanism by which the policy affects market entry and exit lies in the higher quality requirements imposed by the policy，thereby increasing the compliance risks faced by enterprises To verify this mechanism，this paper employs a differenceindiscontinuity design and finds that the consumer protection policy has a more significant impact on enterprises selling hightech products or heterogeneous products，which are relatively more complex Further analysis also reveals that the policy significantly increases the prices and sales of incumbent products
The relevant conclusions have high guiding value in practical aspects such as guiding the improvement of consumer protection policies on CBEC platforms This paper has the following policy implications：First，CBEC platforms should increase the economic penalties for qualityviolating enterprises As pointed out in the theoretical analysis，only higher economic penalties can form a credible threat to enterprises，increase their compliance risks，and prompt them to strictly adhere to product quality regulations Second，CBEC platforms should reasonably adjust the implementation intensity of consumer protection policies based on the characteristics of different enterprises For enterprises selling hightech or heterogeneous products，the compliance risks are greater，and the role of consumer protection policies is relatively more significant Given the limited resources and attention of platforms，these types of enterprises should receive heightened focus Third，the government should promptly supervise the formulation and implementation of platform consumer protection policies to avoid excessive intervention or support towards market entities，ensuring the reasonableness，fairness，and effectiveness of the policies

Key words: cross-border e-commerce, consumer protection policy, reverse selection, compliance risk

摘要： 逆向选择问题是跨境电商“健康持续创新发展”的重要阻碍，而消费者保护政策作为一种重要的平台规制机制，为应对逆向选择问题提供了有益的解决途径。本文使用包含Wish上详细产品信息的数据集，以欺诈性履行订单政策为准实验，采用时间断点回归检验了消费者保护政策对产品市场进入和退出的影响。研究发现，消费者保护政策会显著减少企业的新产品数量，但会显著增加其中高质量产品的数量；同时，政策会促进在位产品的退出，主要体现为低质量产品的退出，从而有效缓解了平台上的逆向选择问题。差分-断点回归表明，核心机制在于消费者保护政策对于产品质量提出了较高的要求，进而提升了企业面临的合规风险。研究还发现，政策会显著提升在位产品的价格和销量。相关结论为跨境电商平台治理“柠檬市场”提供了重要参考。

关键词: 跨境电商, 消费者保护政策, 逆向选择, 合规风险