科创板的设立是中国资本市场的重大制度创新，其是否以及如何提升IPO定价效率是亟待回答的关键问题。不同于核准制，股票发行注册制采取市场化的询价定价机制，并限定询价对象为七类专业机构投资者，充分将判断企业价值的权力交还给市场参与者，打破了主板“23倍市盈率”上限的隐形天花板，同时辅以一系列配套制度来防范IPO估值泡沫问题；此外，注册制还对IPO过程中发行企业与投资者间的沟通机制进行了优化，通过公开披露审核问询回复函等措施提高了新股发行过程中的信息披露质量，有效缓解了存在于发行人与投资者间的信息不对称问题。通过比对分析本轮注册制改革与历次新股制度改革内容，本文提出科创板可能通过市场化定价与缓解信息不对称两大机制实现IPO定价效率的改善。

本文基于2019~2022年间A股市场785个IPO事件，使用连续型队列双重差分模型进行因果识别发现：行业估值越高、信息不对称问题越严重的企业，其在科创板上市相对于在其他板块上市的IPO抑价程度显著更低，即IPO定价效率显著更高。拓展检验揭示，行业估值越高的企业，其在科创板上市的融资规模相对于其他板块显著更大，上市后的研发投资也显著更多；行业信息不对称问题越严重的企业，其在科创板上市时在招股说明书中披露的信息数量显著更多、信息质量也显著更高，说明科创板注册制改革显著改善了企业的投融资状况以及企业IPO时的信息披露质量。上述发现在替换关键变量的衡量方式、进行安慰剂检验后均稳健成立。

本文以注册制改革的两大核心措施为出发点，实证分析了科创板提升IPO定价效率的机制，在A股市场IPO注册制全面推行的背景下，本文为降低企业直接融资成本、增强金融服务实体经济功能提供了有益启示。

The establishment of the STAR market is a major institutional innovation in China's capital market. Whether and how it can improve IPO pricing efficiency is the key question that needs to be answered. Unlike the approval system, the IPO registration system adopts a market-oriented inquiry and pricing mechanism, and limits the inquiry to seven types of professional institutional investors. The system has fully returned the power to judge the value of enterprises to market participants, breaking the invisible ceiling of the "23 times P/E ratio" on the main board. Meanwhile, the registration system is complemented by a series of supporting systems to prevent IPO valuation bubbles. In addition, the registration system also optimizes the communication mechanism between issuers and investors during the IPO process, and improves the quality of information disclosed during the IPO process by publicly disclosing the audit inquiry letter and response letters, which effectively alleviates the information asymmetry between issuers and investors. By analyzing the content of the current round of registration system reform and previous IPO reforms, this paper suggests that the STAR market may achieve improvements in IPO pricing efficiency through two mechanisms: market-based pricing and information asymmetry mitigation.

Based on 785 IPO events in the A-share market between 2019 and 2022, this paper uses a continuous cohort difference-in-differences model for causal identification and finds that firms with higher industry valuations and more severe information asymmetry have significantly lower IPO underpricing on the STAR market compared with those listed on other markets, which means STAR market has significantly higher IPO pricing efficiency. Additional tests reveals that firms with higher industry valuation have significantly larger financing and more R&D investment after IPO on the STAR market relative to other boards; firms with more severe information asymmetry in their industries have significantly more quantity and higher quality information disclosure during their IPO on the STAR market compared with those listed on other markets, indicating that the registration system reform on STAR market significantly improves enterprises’ investment and financing situation and the quantity and quality of IPO information disclosure. The above findings are robust after replacing the measurement of key variables and conducting placebo tests.

Starting from the two core measures of the registration system reform, this paper empirically analyzes the mechanism of the STAR market to improve IPO pricing efficiency. In the context of the full implementation of the IPO registration system reform in the A-share market, this paper provides useful insights for reducing the costs of direct financing for enterprises and enhancing the function of financial services for the real economy.