This study analyzes the financial efficiency of Gam Bonds in Iran’s steel supply chain using a Supply Chain Finance (SCF) approach and Cooperative Game Theory. The Cash Conversion Cycle (CCC) was employed as an operational measure of financial performance to evaluate how Gam bonds reduce the need for working capital across supply chain members. A case study was conducted on three key steel companies—Gohar Zamin, Kavir Steel Kaveh, and Fratarh Foolad—using financial statements and expert assessments. The results indicate that adopting Gam bonds leads to a significant reduction in the total CCC by 109 days, consisting of 104 days of independent improvement and 5 days of synergy created through full chain cooperation. Based on the Shapley value analysis, the fair allocation of benefits among firms was 76.5, 11, and 21.5 days respectively, highlighting the crucial role of upstream firms in initiating liquidity flows. The findings confirm that supply chain–based financial cooperation through Gam bonds enhances overall liquidity efficiency, decreases financing costs, and fosters sustainable collaboration. Applying the Shapley value ensures a fair and transparent distribution of financial gains, strengthening incentives for long-term cooperation within industrial supply chains.