This study examines how major customers with significant bargaining power impact suppliers' disclosure practices. By examining the relationship between customer concentration and the quality of suppliers' risk factor disclosures, we find that firms with a concentrated customer base tend to provide more detailed risk disclosures. This trend reflects the pressure from major customers on suppliers to disclose comprehensive risk profiles, enabling customers to assess potential risks to their own performance. The impact of customer concentration on disclosure quality is particularly pronounced when significant relationship-specific investments in the supply chain exist. Moreover, customer demand for risk disclosures varies with external economic uncertainty and supplier resilience. These findings underscore the critical role of non-shareholder stakeholders, such as major customers, in shaping firms' financial reporting decisions, which are crucial for market participants.