The tape this week did not print a consumption boom. It printed a split. COMEX September copper stamped an all-time high of US$6.7775 per pound — US$14,940 a tonne — on Wednesday 26 August, after a record settlement of US$6.7140/lb the session before. LME three-month touched US$14,251/t, a whisker under January’s record of US$14,527.50/t. By Thursday 27 August the COMEX contract had given back about 1.6 per cent, to around US$6.58/lb, as fresh metal hit LME sheds and the immediate shortage eased. That rundown is the International Copper Association Australia’s weekly compilation of the exchanges and the wires — a trade-association brief, not an LME official file. [1]

Records on one board. Relief by delivery on the other. That is not a demand print.

Two weeks earlier the London cash contract had already shown the mechanism in the raw. Andy Home, writing for Reuters (syndicated on Zawya), had cash’s premium over three-month balloon to US$545/t on the Monday — the widest backwardation since the 2021 squeeze — with cash itself a record US$14,912/t. LME stocks had closed the prior week at a six-month low of 207,825 tonnes; live, on-warrant metal was 103,075 tonnes. Then 38,150 tonnes were delivered into LME warehouses over three days, 17,300 of them into Baltimore and New Orleans. Backwardation retreated to US$176/t. [2]

MINING.COM, citing Benchmark Mineral Intelligence, has the on-warrant bounce that broke the immediate pinch: 63,000 tonnes onto warrant between Monday 17 and Wednesday 19 August, even as total LME stocks gained a smaller 28,000 tonnes — cancelled metal coming back onto the board. Cash-to-three-month had widened to nearly US$550/t on the Monday, then fell to about US$176/t Wednesday from US$436/t at Monday’s close. Three-month traded US$13,885/t that Wednesday. Benchmark copper analyst Albert Mackenzie’s line is the one the desk is keeping: “Lots of the current odd dynamics have come as huge amounts of copper heads to the US due to the high arbitrage caused by tariff uncertainty, making the global market feel tighter than it really is.” And: “As long as there is uncertainty on tariffs, situations like this could arise again.” [3]

The constraint is not that the world ran out of cathode. The constraint is where the cathode is allowed to sit.

Home had CME warehouses holding 58 per cent of global exchange inventory at the end of July. The ICA brief has COMEX registered stocks past 675,000 tonnes — up roughly eightfold since February 2025, after 46 consecutive daily builds — and more than 200,000 tonnes of copper into US ports in July alone. Yahoo Finance has the COMEX pile at a record 675,185 tonnes after those same 46 sessions, US refined-cathode imports at almost 885,000 tonnes in the first half of 2026, and a record 1.64 million tonnes for calendar 2025. [1][2][5]

America is not consuming that metal at the rate it is arriving. It is parking it.

The hanging decision is in blackletter, and it is a year old. The White House proclamation of 30 July 2025 — “Adjusting Imports of Copper into the United States” — put a 50 per cent tariff on semi-finished copper products and intensive copper derivatives from 1 August 2025. The Commerce Secretary’s June 2025 report, as recited in that proclamation, had recommended a phased universal tariff on refined copper: 15 per cent from 2027, 30 per cent from 2028. Clause (7) required Commerce to give the President an update on domestic copper markets, including refining capacity and the refined-copper market, by 30 June 2026, “so that the President may determine whether imposing” that phased refined-copper duty “is warranted.” [4]

The desk has not seen a public presidential determination imposing a duty on refined cathode. We are not writing that Commerce failed to file the update; we do not have that primary filing. What we have is the proclamation’s date, still hanging, and no public call from the President either way. The ICA brief compiles the same vacuum as “Washington missed the 30 June deadline,” and reads the COMEX–LME spread as a tariff-risk gauge. That is a trade-association line, not a Commerce docket. Distinguish them. [1][4]

Until that call is made — duty on, or duty off — the arbitrage stays open. Home’s numbers: the CME premium for three-month was US$430/t, and for ten-month delivery more than US$1,000/t. His line, not ours: the US pull “will remain so until President Donald Trump provides some clarity” on refined-copper tariffs. ICA had cash-to-three-month blow out beyond US$500/t intraday in the latest week, then narrow to about US$127/t by Tuesday’s close. The squeeze eases when metal is warranted. The pull does not. [1][2]

CRU’s Robert Edwards, as reported by Yahoo Finance, is blunt about the accounting trick the tariff threat has performed: it has turned what should have been a surplus into “at best a balanced market” if the metal accumulated in the United States is removed from global availability. CRU had previously forecast a 639,000-tonne surplus for 2026. That is not the desk calling a deficit. It is CRU saying the surplus is in the wrong country. [5]

And the demand tape, such as it is, is not doing the work the headlines want. The same ICA weekly — again, a compilation, not an SMM print we opened — has Chinese cathode-rod operating rates at 58.89 per cent, down 3.67 percentage points week-on-week. Fabricators slowing in the world’s largest consuming market while COMEX prints records is the tell. The world did not suddenly need more wire. Traders needed a shed inside a tariff wall that may or may not be built. [1]

Glencore ($GLEN) chief executive Gary Nagle, quoted in that same Yahoo Finance piece — we did not open the earnings transcript — argues that uncertainty is the bigger driver than the tariff itself, and that any announcement, zero, 15 per cent or 30 per cent, could knock the price because traders would finally have a number. The desk’s read of that line: the option is what is being bid, not the duty. Do not confuse the two. [5]

Who is winning is the flow. Cathode that can still clear into COMEX without a refined-copper tariff is being paid to move. Who is offside is anyone treating LME cash as a global consumption print, and anyone treating a COMEX record as proof the world has run out of metal. London shorts rolling against a warehouse system that has been drained toward American ports are paying the tuition. The Section 232 refined-copper decision is option value on the curve — not a base case. We are not forecasting that the duty lands. We are saying the tape is pricing the hang. Treat every London squeeze, until Washington speaks, as a preview — not a climax. This is analysis. It is not investment advice. The desk is not telling you to buy or sell copper, a miner, or a warehouse receipt.

The desk’s owner is an active miner and investor. Assume a possible position in or near the metal or the names in this piece. This is independent commentary, not financial, legal, or tax advice. Readers should verify company filings and exchange data themselves. Past performance and commodity prices change.

Sources

  1. International Copper Association Australia, Copper Weekly Brief, week ending 28 August 2026. Trade-association compilation of LME/COMEX prints and newswire data — not an LME official file. https://copper.com.au/news/mining/copper-weekly-brief-week-ending-28-august-2026/

  2. Andy Home, Reuters column, syndicated on Zawya, 19 August 2026. Attribute as Andy Home, Reuters (via Zawya syndicate). https://www.zawya.com/en/business/insights/lme-gripped-by-flash-squeeze-as-copper-tensions-boil-over-andy-home-461246

  3. MINING.COM, “Copper inventories surge 50%, easing LME squeeze,” citing Benchmark Mineral Intelligence. https://www.mining.com/copper-inventories-surge-50-easing-lme-squeeze/

  4. White House, Proclamation, 30 July 2025, “Adjusting Imports of Copper into the United States.” Clause (7) is the hanging 30 June 2026 Commerce update. No public presidential determination imposing a refined-cathode duty found. https://www.whitehouse.gov/presidential-actions/2025/07/adjusting-imports-of-copper-into-the-united-states/

  5. Yahoo Finance, “US tariff risk disrupts copper surplus as prices approach record high.” CRU’s Robert Edwards and Glencore CEO Gary Nagle as reported by this article; earnings transcript not opened. https://finance.yahoo.com/markets/commodities/articles/us-tariff-risk-disrupts-copper-092457525.html

Opinion and commentary — the desk’s own views, grounded in the sourced facts above. Facts are sourced; views are clearly labeled as such and are not statements of fact about any named party. See our Ethics & Disclosure policy. Nothing here is investment, financial, legal or tax advice. Spotted an error? Tell the desk — we correct in the open.

The Take (conviction 4/5): This week’s copper tape is tariff risk on the curve, not a consumption boom. COMEX is sitting on a record pile; London is bidding for what is left. Until Washington puts a duty on refined cathode or says it will not, every London squeeze is a preview, not a climax. Analysis, not a price forecast, not advice.