What are the implications of major customer dependency, i.e., the degree of a supplier firm's dependency on its major customers, for external auditors? While the conventional view emphasizes the negatives of major customer dependency for client business risk, we find that suppliers with more concentrated customer bases spend less on audit fees. The evidence is consistent with reduced audit effort due to efficiency gains in the audit process, especially when suppliers with more concentrated customer bases share the same auditors with their long-standing major customers. The audit fee discount we identify does not imply that audit quality declines with customer-base concentration. In fact, we find that suppliers with more concentrated customer bases are less likely to experience material restatements of previously audited financial statements. Taking the external auditors' perspective, our study provides new managerial insights on the costs and benefits of major customer relationships for supplier firms.
Data Availability: All data are available from sources identified in the text.