White House Copper Tariff Delay Erases 4.6% in US Prices as Supply Gap Stays Intact
A Reuters report on stalled refined copper tariffs triggered sharp losses across mining stocks on Thursday, exposing trade positioning built atop an unresolved supply deficit.
Copper futures and mining equities sold off sharply on Thursday (2026-09-10) after Reuters reported the White House has yet to decide whether to impose tariffs on refined copper, with officials weighing manufacturing cost concerns against the potential benefit to domestic producers. US copper prices fell 4.6% and Goldman Sachs's US Metals basket shed nearly 3%.4
The selloff reversed a trade that had built over the prior sessions. LME copper three-month benchmark futures hit $14,533 a tonne on Tuesday (2026-09-08), a fresh record exceeding January's prior peak, as expectations of US tariffs drew record volumes of seaborne copper into US warehouses and tightened availability elsewhere. Bloomberg data show the metal has climbed 17% year-to-date and 47% over the past twelve months.3
The US-LME copper spread, which had been running at a 10-15% premium, roughly halved after the Reuters report, traders noted. The arbitrage that had driven physical flows toward US ports unwound quickly.4
Mining equities bore the brunt. Freeport-McMoRan fell 8% on Thursday (2026-09-10). Southern Copper dropped 7%, Teck Resources slid 7.9%, Ero Copper declined 8.6%, Capstone Copper lost 8.2% and First Quantum Minerals retreated 6.4%.4
But none of that equity damage changes the physical supply picture. Deutsche Bank analysts estimate mine output, which fell in 2025, will be roughly flat in 2026. "The supply issue isn't a quick fix," Shaun Usmar, who runs a mining-focused fund, told the Economist. Goldman's Adam Gillard noted in a client note that LME copper's record came on volume running at 80% of the year-to-date average — not a thin, momentum-only move.1,3
The structural constraint goes beyond any tariff cycle. Robert Friedland, speaking on Bloomberg's Odd Lots podcast, argued that the mining industry's adoption of net present value models, borrowed from the oil and gas sector, systematically undervalues long-lived ore deposits. "Mines cannot be modeled to NPV," Friedland said, contending that discounting distant production at prevailing cost-of-capital rates suppresses asset valuations and, with them, new mine investment. Recent years of underinvestment, flat output and surging prices fit that reading, though the argument is not universally accepted across the industry.5
The merger wave now reshaping the sector reflects the same supply shortage from a different angle. Rio Tinto has confirmed talks to acquire Glencore, a move that would create the world's largest miner at roughly $220bn in combined market value, the Economist reported. Glencore shares rose 10% when the deal was announced on January 8th (2026-01-08); Rio's fell 3% before recovering. The total value of mining tie-ups in 2025 hit $94bn, the highest in a decade.1
Buying existing mines adds scale but not new ore. The deeper constraint runs through the Democratic Republic of Congo, where Chinese entities hold stakes in roughly 90% of Congolese mining projects, according to the Economist. In February 2026, Orion CMC, a consortium that includes the US government, agreed to buy a 40% stake in the only Western-controlled copper and cobalt mines in the country, a move that signals Washington has started treating mine access as a strategic matter rather than a commercial one.2
For the copper market, the next signal is a White House decision that has not come. The administration's affordability concerns mean a refined copper tariff could still be imposed, revised or dropped, with each path carrying different implications for the US-LME spread and for the mining equities that rallied on the tariff trade. Physical mine supply is flat, demand from AI data centres and power grid build-out is growing, and the new-project pipeline is thin. The policy delay is short-term noise on top of a supply story that is not resolving quickly.4,1