Copper jumped nearly 1% on the LME to $11,294.50/ton, while Comex futures surged 1.6%, blowing out the US-London spread as traders scramble to rush metal into the U.S. ahead of potential Trump-era import tariffs.

The arbitrage continues to pull supply from the rest of the world into the U.S., compounding a year already plagued with unexpected mine outages and tightening fears.

Goldman's commodity specialist, James McGeoch, commented on this dynamic, calling it a "circular melt-up":

Post Thanksgiving – breakout in Copper: Have been watching LME, that $11,100 level, now 3 times, it's felt like a coiled spring, we have seen it in precious this year (Gold, Silver, PGM's), so why not pivot to the Doctor. As we do just remember commodities are highly emotive, basis the touch point at all levels of life, they rarely move in linear fashion, overreact up and overreact down, look at the awakening in Rare Earths in 2025. Whilst the CESCO feedback from a bottom-up perspective was kinda meh (China -8% QTD, y/y, worth noting YTD +7% y/y to end Oct), it's the balances that matter. This wasn't a conference about mine supply, or Chinese Q4 demand, this was dominated by the traders and the desire to purchase and ship into the Comex (U.S.) arb. GS commods sales were on the ground (feedback link), outside China they note EUR demand <2019 and they suggest positioning is 5/10….

I liken this to a "circular melt-up." The tighter LME gets tighter basis US (CMX arb) pull, the stronger the LME backwardation, which in turn tightens the CMX arb as the forward curve is underpinned by stock builds….. Circular motion – LME stock contraction, CMX arb strengthens…. Those watching supply have for some time been looking at 1H26: Grasberg tightness, Kakalua stockpiles rundown, Codelco friction, Collahuasi weakness, QB sustains lower rates. China smelter utilisation rates at record lows, copper premiums at record highs, TC settlement structures are breaking… there is nothing the Chinese can do about it, and in the meantime the U.S. is sitting whistling Dixie as stocks get onshored, it's a strategic stockpile, basis the "threat" of tariffs, that they so desperately need and the traders are providing the balance sheet. Who would have thought 12 months ago that the U.S. would be the only game in town when it comes to copper. By luck or by design, Uncle Sam holds all the aces…. I think last week's move was the hangover of CESCO washing off and traders realising that near term the asymmetry is higher. … Colleagues gone reminded us daily, commodities are spot assets, they are not traded in Excel models, they are art as much as science. Go back to summer, the same traders that owned CMX at 500, sold it at 550/575, the guys that got slammed as the unwind happened were machines. It's these same buyers today stepping in.