二手车市场有着鲜明的“柠檬市场效应”特征，由信息不对称引发的交易低效长期困扰着这一市场。自1970年Akerlof提出柠檬市场理论以来，学术界从形成机制和解决策略等方面进行了广泛而深入的探讨，然而在实践中，柠檬问题似乎很难解决。2022年，中国二手车交易量达到1603万台，交易额突破1.06万亿元，标志着这一市场已步入万亿规模，尽管市场规模不断扩大，但二手车交易的核心问题仍未得到根本性缓解。信息披露不充分、交易透明度不足以及跨区域车源配置低效等问题，继续制约着中国二手车市场的健康发展。 近年来，随着电商平台入局二手车交易赛道，传统的二手车交易模式出现了新的变革。新兴的商业模式引入了线上交易、数据驱动的定价机制以及更透明的车辆信息披露等手段，试图改变以往信息不对称的局面。然而，创新的商业模式能否切实提高二手车市场的效率，形成一个可持续的盈利模式，还是只是在资本热潮推动下通过广告、补贴、低价等手段吸引用户和扩大市场份额的短期繁荣，这一问题引发了广泛关注。其本质是需要回答能否在一定程度上缓解了柠檬市场问题，真正创造了市场价值。 本研究基于瓜子二手车平台一项田野实验的真实交易数据，探讨了电商平台在缓解柠檬市场问题中的作用，特别是定金机制的应用。研究发现，定金支付阶段较高的定金比例能够有效筛选出更有意愿的买家，减少低质量交易，进而缓解了逆向选择和道德风险问题。然而，在定金支付后至最终交易完成的阶段，定金高低对交易完成率的影响并不显著。借助电商平台提供的高信息透明度及其他辅助机制，买家在支付定金前通过这些信息充分了解车辆状况，并在心理上确认了购买意图，能够做出更加理性的决策，这使得定金的约束作用相对减弱。 本研究的结果表明，二手车电商平台可以通过提高信息透明度和提供多种交易保障机制，在一定程度上缓解柠檬市场问题，减少信息不对称带来的负面影响。同时，定金机制可以作为辅助工具，提高交易初期的筛选效率，但其对最终交易决策的影响有限。这为二手车市场如何设计更加有效的交易保障机制提供了重要的实证依据，也为提升行业整体交易效率提供了新的思路和启示。
The lemon market problem in the used car market has long been a traditional financial issue, with inefficiencies in transactions caused by information asymmetry persistently troubling this market. Since Akerlof introduced the lemon market theory in 1970, academia has extensively and deeply explored the mechanisms behind this issue and potential solutions. However, in practice, the lemon market problem appears difficult to resolve. In 2022, China’s used car transaction volume reached 16.03 million units, with a transaction value exceeding 1.06 trillion yuan, signifying that this market has entered the trillion-yuan scale. Despite the continuous expansion of market size, the core issues in used car transactions have yet to be effectively and fundamentally addressed. Inadequate information disclosure, insufficient transaction transparency, and inefficiencies in cross-regional vehicle distribution continue to hinder the healthy development of China’s used car market.In recent years, with e-commerce platforms entering the used car trading market, the traditional mode of used car transactions has undergone significant changes. These emerging business models have introduced online transactions, data-driven pricing mechanisms, and more transparent vehicle information disclosure, aiming to address the previous issues of information asymmetry. However, whether these innovative business models can genuinely enhance the efficiency of the used car market and establish a sustainable profit model, or if they represent merely a short-term boom driven by capital through strategies such as advertising, subsidies, and low prices to attract users and expand market share, has become a topic of widespread concern. The core question is whether these models have, to some extent, alleviated the “lemons market” problem and truly created market value.This study, based on real transaction data from a field experiment on the Guazi used car platform, explores the role of e-commerce platforms in mitigating the “lemons market” problem, with a particular focus on the application of the deposit mechanism. The findings indicate that a higher deposit ratio during the deposit payment stage can effectively filter out more committed buyers, reducing low-quality transactions and thereby alleviating issues of adverse selection and moral hazard. However, after the deposit payment and before the final transaction completion, the amount of the deposit does not significantly impact the transaction completion rate. Leveraging the high level of information transparency and other supporting mechanisms provided by the e-commerce platform, buyers are able to make more informed and rational decisions before paying the deposit by thoroughly understanding the vehicle’s condition and psychologically confirming their purchase intention. As a result, the binding effect of the deposit is relatively weakened.The findings suggest that used car e-commerce platforms can, to some extent, mitigate the lemon market problem by enhancing information transparency and offering various transaction safeguards, thus reducing the negative effects of information asymmetry. While deposit mechanisms can be useful in the early stages of transaction screening, their influence on the final transaction decision appears limited. This study provides valuable empirical evidence for designing more effective transaction protection mechanisms in the used car market and offers fresh insights for improving overall market efficiency.
