Abstract: Anhui Province is located at the intersection of strategic overlays, including the Yangtze River Delta Integration and the Yangtze River Economic Belt. How does the trend of financialization among listed companies within the province manifest? Moreover, relational transactions are a typical characteristic of China’s business model. What impact do they have on corporate financialization? Taking the non-financial listed firms on the Shanghai and Shenzhen A-shares in Anhui Province as the research object from 2012 to 2022, the influence of inter-firm relational transactions (between customers and suppliers) on the financialization process of enterprises in Anhui Province was explored, and the transmission paths and mechanisms involved in this process were analyzed. The findings reveal that the concentration of customer/supplier among listed firms in Anhui Province effectively inhibits firms’ financialization behaviors, with a more pronounced effect observed in non-state-owned enterprises and those with higher governance standards. The alleviation of financing constraints and agency costs provides an important foundation for this restraining effect. These results enrich the theories related to relational transactions and corporate financialization, aiding in the understanding of the drivers of financialization among physical entities in Anhui Province. On one hand, it alerts listed firms in Anhui Province to balance the impact of supplier/customer concentration, promoting collaborative efforts up and down the supply chain to enhance enterprise value. On the other hand, it prompts the government and capital markets to comprehensively recognize the phenomenon of “moving away from the real economy towards speculation”, providing guidance for regulators and policymakers to prevent systemic risks in the financial sector and ensure the safety of the financial system.