US has built a strategic copper reserve. Now can it keep it?
XLB•The US copper stockpile has grown to about 1.1 million metric tons, driven by the premium on CME copper prices. Whether it stays in the country may depend on tariffs, market prices or purchases for Project Vault.
1. Stockpile expands
The US now holds more than a million metric tons of copper, with Citi analysts estimating the stockpile at around 1.1 million tons after allowing for off-market inventories. CME registered stocks have risen from 88,595 metric tons in February last year to 711,617 tons, while US LME warehouses hold another 251,128 tons of registered and off-warrant stocks.
2. Market forces at work
Copper has flowed into the US since a national security probe into imports began in February 2025, as CME prices traded at a premium to London Metal Exchange prices. Tariffs announced in July 2025 covered copper products, but the White House has not set out a concrete policy for refined copper.
3. Keeping the copper
The current stockpile is commercially owned and could leave if market conditions change. The White House could impose tariffs on refined copper, potentially phasing them in at 15% in 2027 and 30% in 2028, or channel copper into Project Vault, a new public-private mineral reserve. But a fixed tariff could be overtaken by international prices, and buying copper for the reserve would be costly.
