Critical Commodity Shock Vulnerability in Global Trade: A Margin-Based Screening Framework

Commodity shocks can generate material cross-border exposure because energy, food, industrial metals, and critical minerals are essential inputs to production and consumption. This article develops a transparent, margin-based screening framework for eight commodity categories using 2024 WITS/UN Comtrade reporter-to-world top-country data. The empirical design combines export- and import-side concentration, normalized entropy, an explicit non-substitutability scenario parameter, and a dimensionless trade-scale adjustment. A maximum-entropy independence matrix, pijk = eik mjk, is retained only as a null exposure benchmark; because it is rank one and contains no bilateral information beyond the observed margins, the study does not interpret it as a recovered trade network and does not report graph centrality. The revised results identify copper ores as the highest scale-adjusted vulnerability layer, followed by crude petroleum and liquefied natural gas; lithium carbonates remain highly concentrated but rank lower once trade scale is normalized dimensionlessly. Cobalt ores are retained only as a diagnostic illustration of HS-proxy fragility and are excluded from headline country rankings. Country-level tables report observed exporter and importer shares directly rather than redundant composite transmitter and receiver scores. Sensitivity analysis shows that the commodity ordering is robust to uniform and compressed non-substitutability scenarios and to broad parameter perturbations. Historical plausibility checks against the 2021–2022 European gas shock, Indonesia’s nickel-ore export restrictions, and the 2022 wheat disruption are directionally consistent with the screening signals, although they do not constitute causal validation. The framework is therefore intended as an early-warning screening device, not a graph-theoretic propagation model or a macroeconomic-loss estimate.