U.S. President Donald Trump’s announcement of a 50% import tariff starting next month has delivered a dual shock to the copper market. Expectations had been for a lower tariff rate with a longer buffer period, but the sudden policy shift has forced rapid strategic adjustments. Copper contracts on the Chicago Mercantile Exchange (CME) have repeatedly hit record highs due to widening tariff differentials with London Metal Exchange (LME) contracts, while physical supply chains face severe disruptions. The August 1st effective date means the window for shipping metal to the U.S. for tariff arbitrage is closing, with only a handful of traders who pre-shipped cargoes able to complete transactions before the deadline.
Since the Trump administration launched a national security investigation in February into U.S. copper import dependence, tariff trade has become a key profit driver for merchants and traders. As large volumes of copper were diverted for arbitrage, physical supply chains and exchange markets (such as the LME and Shanghai Futures Exchange) faced tightened supply. Between March and May, U.S. refined copper imports surged to 541,600 metric tons—equivalent to 60% of total 2024 imports. Beyond traditional suppliers Chile and Peru, shipments from Australia, Asia, and Europe also accelerated into the U.S. market. CME warehouse stocks have more than doubled since early March, reaching 222,723 tons, nearing 2018 peak levels. Citigroup analysts suggest these inventories could “offset U.S. copper import demand for the rest of 2025,” while Macquarie notes that factoring in ongoing long-term contract inflows, clearing the stockpile could take up to nine months.
With the U.S. import window closing, global supply chains are recalibrating. LME inventories rose by 33,525 tons this month, partly due to accelerated exports from Chinese producers. Since March, China’s refined copper exports have grown steadily, replenishing LME stock drawdowns and easing price spread pressures. The LME benchmark spread has now shifted from a $300+/ton discount in late June to a $66/ton premium, signaling rebalanced supply and demand.
