Dynamic Pricing Power Shifts in Global Copper Markets: A Multi-Time-Scale Time-Varying Information Share Model

In the context of global energy transition and carbon neutrality goals, copper—an essential energy metal—plays a vital role in securing supply chain stability, enhancing industrial competitiveness, and promoting green development. This paper investigates the dynamic evolution of price discovery across major global copper markets—COMEX, LME, SHFE, and China's spot market—from January 4, 2011, to April 30, 2025. By applying a multiscale empirical mode decomposition (EMD) method and integrating the VECM-DCC-GARCH framework with a time-varying information share (TV-IS) model, we assess pricing efficiency across different time horizons.Our findings suggest: (1) At the single time scale, copper futures traded on COMEX and LME exhibit dominant short-term price discovery capability, while China's spot copper market demonstrates superior pricing strength during periods of major market disruptions; (2) At both mid- and low-frequency scales, China's spot market consistently leads in price discovery, whereas SHFE futures show room for improvement; (3) Price discovery dynamics vary across time scales, though each market displays relative internal stability; (4) Overall, China's spot and SHFE markets jointly exhibit superior pricing capability across scales. These insights offer valuable implications for cross-market hedging strategies, exchange design improvements, and systemic risk detection by regulators.