US Copper Stockpiles Mask Global Shortages

A growing concentration of copper inventories in US warehouses is masking tightening supplies elsewhere, creating a fragmented global market where a surplus can coexist with shortages and elevated prices, according to a study by GEM Mining Consulting cited by Mining.com.

Nearly 70% of the world's visible exchange copper stocks are now held in the US, representing a dramatic shift from historical patterns. Global inventories reached 1.04 million tonnes in October, up 83% from a year earlier, but much of that metal is effectively separated from buyers in other markets. The analysis shows that COMEX warehouses held 718,000 tonnes of copper in October, accounting for 69% of visible stocks across the London Metal Exchange (LME), COMEX, and Shanghai Futures Exchange (SHFE).

Diverging Forecasts and Tariffs

The inventory imbalance helps explain conflicting forecasts for 2026. The International Copper Study Group (ICSG) projects a global refined copper surplus of 104,000 tonnes, while Goldman Sachs estimates a deficit of roughly 950,000 tonnes outside the US and expects prices to reach $14,700 per tonne by year-end. BMO Metals and Mining researchers have also flagged a widening disconnect between muted futures price movements and tightening physical supplies.

The accumulation in US warehouses accelerated after Washington launched a Section 232 investigation into copper imports in February 2025. Between February and July 2025, COMEX copper traded at an average premium of about $1,120 per tonne over LME prices. Although the premium collapsed after Washington excluded refined copper cathodes from a 50% import tariff announced in July 2025, 77% of the 633,000 tonnes added to COMEX inventories since February 2025 arrived after that announcement, driven by uncertainty over potential future duties.

Regional Supply Pressures

Physical market indicators in China show tightening supplies, with China's Yangshan cathode premium climbing above $200 per tonne and Shanghai premiums for non-registered equivalent cathodes reaching record levels. Meanwhile, supply risks are emerging in Africa as BMI warns that the Democratic Republic of Congo and Zambia could face electricity shortages from drought, potentially disrupting production.

Key facts

• Nearly 70% of the world's visible exchange copper stocks are held in the US, with COMEX inventories reaching 718,000 tonnes in October.
• Global exchange inventories reached 1.04 million tonnes in October, up 83% year-over-year.
• Goldman Sachs projects a deficit of 950,000 tonnes outside the US with prices reaching $14,700 per tonne by year-end.
• China's Yangshan cathode premium climbed above $200 per tonne amid tightening physical supplies.