US Copper Stockpiles Surged Past One Million Tons
Tariff threats fueled a massive inflow of copper to U.S. warehouses, pushing total stockpiles to 1.6 million tons.
Updated on Oct. 14, 2026 in International Trade
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United States copper stockpiles surpassed 1 million metric tons following trade policy shifts, as traders sought to profit from arbitrage opportunities. On September 22, 2026, Comex copper prices hit a record $6.83 per pound.
Why it matters
The massive accumulation was triggered by an arbitrage price gap between Comex and the London Metal Exchange, which widened to over $3,000 per ton in July 2025. This stockpile reflects market anticipation of future tariff implementation.
Comex copper stocks have increased by 750% since February 2025, with domestic holdings now accounting for 70% of global visible stocks. The current arbitrage gap between Comex and the London Metal Exchange has narrowed to $310 per ton.
The players
Donald Trump
He is the current President of the United States who initiated the study on potential copper tariffs in February 2025.
The details
Traders moved significant quantities of metal into Comex-approved warehouses, including facilities in New Orleans and Baltimore, following a February 2025 order for a study on potential copper tariffs. Current projections indicate the United States will hold a surplus of 1.6 million tons by the end of 2026.
Timeline
February 2025: President Donald Trump ordered a study on potential copper tariffs.
July 2025: The arbitrage price gap between Comex and the London Metal Exchange reached a record peak.
September 22, 2026: Comex copper prices reached a record high of $6.83 per pound.
January 1, 2027: A 15% tariff on refined copper imports is scheduled to take effect.
Market Dynamics
This influx of copper follows a broader trend of market volatility linked to anticipated trade protectionism. The stockpile buildup represents a departure from standard supply-chain logistics, as traders adjust to the upcoming 15% tariff on refined copper imports.
The volatility in copper pricing may influence commodities-focused portfolio allocations and interest in metal-backed assets. Retail investors should monitor how the narrowing arbitrage gap affects future contract pricing and market stability.
The takeaway
Market participants are actively adjusting to trade barriers, resulting in historically high domestic supply levels. Observers should watch how the 2027 tariff implementation affects the price spread between domestic and international exchanges.
What happens next
A 15% tariff on refined copper imports is scheduled to take effect on January 1, 2027, with a 30% tariff on refined copper imports planned for 2028.
Further reading
For broader context on trade policies, visit the United States International Trade section.
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