基于2007～2022年A股上市公司公开披露的前五大客户与供应商信息，从供应链风险溢出视角，系统考察下游客户影子银行化对于上游供应商审计费用的影响。研究发现，下游客户影子银行化会导致上游供应商审计费用的增加。机制分析表明，下游客户影子银行化通过加剧上游企业经营风险和信息风险，促使审计师提高风险溢价导致审计费用的提升。异质性分析表明，下游客户影子银行化的风险传导效应在产权性质为国有企业、内部治理水平低、外部法治环境差以及审计师具有行业专长的供应商中更为显著。

Based on the publicly disclosed information of the top five customers and suppliers of A-share listed companies from 2007 to 2022, this study systematically examines the impact of downstream customers’shadow banking activities on the audit fees of upstream suppliers from the perspective of supply chain risk spillover. The findings reveal that the shadow banking activities of downstream customers lead to an increase in the audit fees of upstream suppliers. Mechanism analysis indicates that such activities exacerbate the operational and informational risks faced by upstream firms, thereby prompting auditors to charge higher risk premiums and in turn raising audit fees. Heterogeneity analysis further demonstrates that the risk transmission effect of downstream customers’ shadow banking activities is more pronounced when the upstream suppliers are state-owned enterprises, exhibit weaker internal governance, operate in regions with weaker legal environments, or employ auditors with a higher level of industry expertise.