This study reports evidence that concentrated 3‐firm supply chains achieve superior financial performance, and that supply chains’ financial performance varies systematically with measures of chain concentration and chain duration. Results from firm‐level analyses suggest that the profitability benefits of supply chain relationships are captured predominantly by downstream chain members, whereas cash cycle benefits are realized throughout the supply chain. Firm‐level tests also reveal that chain members’ financial performance varies systematically with measures of downstream bargaining power, downstream relationship duration, and degree of supply consolidation. The study's chain‐ and firm‐level analyses employ data extracted from sample firms’ publicly available financial reports, including their major customer disclosures under Statement of Financial Accounting Standards Nos. 131 (1997) and 14 (1976).