This study aims to investigate the “credit transmission capacity” within the supply chain of Iran’s steel industry, focusing on the role of innovative financial instruments such as “Gaam Bonds” in managing working capital. The central problem addressed is identifying the optimal threshold for applying these instruments in multi-tier supply networks, where institutional costs and systemic risks may outweigh financial benefits. Adopting an analytical-qualitative approach and leveraging theories from institutional economics and production network analysis, this study demonstrates that the success of credit transmission is not merely a function of quantitative expansion, but is fundamentally dependent on the “production correlation structure” and the positioning of the instrument within key “anchor” nodes of the network. The findings reveal that the effective depth of credit transmission is a function of the distance from the anchor node. Furthermore, “information asymmetry” and “transaction costs” in deeper supply tiers create a threshold, denoted as d∗d^*d∗, beyond which the efficiency of these instruments diminishes. Comparative analysis shows that Gaam Bonds, due to uncertainties in discount rates and liquidity constraints, possess lower penetration in the steel ingot ring compared to traditional Letters of Credit (LC). Finally, the research suggests that policy-making in this domain should shift from individual firm-level focus toward a network-centric approach, prioritizing liquidity stabilization at strategic bottleneck nodes.