摘要：长期以来，中国债券信用评级制度的有效性备受质疑，急需政府部门充分发挥监管职能，压实信用评级机构的责任。本文基于证券交易所(以下简称交易所)对债券发行上市审核形成的反馈意见文本信息，以2015年5月至2021年12月的公司债券发行数据为样本进行了实证检验。研究结果表明：公司债券发行上市审核问询会显著增加发行人信用评级下调的可能性，这一结论在经过一系列稳健性检验后依然成立。影响机制检验发现，交易所审核问询释放出发行人未来风险较高的信号，导致评级机构更有可能下调发行人的信用评级。基于发行人特征的异质性检验发现，当发行人为民营企业、盈余管理程度较高或未被“投资人付费”评级机构覆盖时，交易所审核问询更可能增加发行人信用评级被下调的概率。基于评级机构特征的异质性检验发现，当评级机构的行业竞争加剧、声誉较差或没有外资背景时，发行人被交易所审核问询后更有可能出现信用评级下调的现象。本文从公司债券发行上市审核问询的视角，丰富了信用评级影响因素的相关研究，对提高信用评级机构执业质量、深化债券注册制改革也具有一定的现实意义。

Abstract: The validity of China's bond credit rating system has long been questioned, making it necessary for government departments to give full exercise their supervisory functions and consolidate the responsibly of credit rating agencies.Based on the review feedback letters formed by the stock exchanges on the review of corporate bond issuance listing, this paper takes the corporate bond issuance data from May 2015 to December 2021 as a sample for empirical testing.The results show that the corporate bond issuance listing review(CBILR) will significantly increase the likelihood of the issuer's credit rating downgrade, and this conclusion is still valid after a series of robustness tests.The mechanism test finds that CBILR releases signals of higher future risks for issuers, resulting in rating agencies being more likely to downgrade issuers' credit ratings.The heterogeneity test based on the characteristics of issuers reveals that the CBILR is more likely to increase the probability of the issuers' credit rating downgrade when issuers are private enterprises, engage in a high level of earnings management, or are not covered by the “investor-paid” rating agency.The heterogeneity test based on the characteristics of rating agencies finds that when the industry competition of rating agencies is intensified, the reputation is poor, or there is no foreign capital background, the issuers are more likely to have a credit rating downgrade after the CBILR.From the perspective of CBILR, this paper has enriched the relevant research on the factors affecting credit ratings, and has certain practical significance for improving the practice quality of credit rating agencies and advancing the reform of the bond registration system.