Build-up of US copper stocks leading to apparent market tightness

Copper prices have hit record high after record high in 2026, and are approaching USD 15,000/t as of 10 September. This is despite 2025’s multi-year high surplus and 2026 looking likely to be a broad surplus too.

Part of the reason prices are not reflecting the strong surplus is that huge flows into the US are making the market feel significantly tighter than it is.

In 2025, so much copper went to the US that Benchmark assessed the market as “feeling” 700kt tighter in 2025 than the actual surplus, and Benchmark expects the perceived tightness to be 880kt lower than the actual surplus in 2026.

Stock build out in the US is not real “demand”. However, flows to the US can feel like demand in the context of the wider market as the material moving to the US is no longer available to the global market and is broadly removed from price formation.

“There is a large amount of invisible stock in the US but even if we look at visible inventories on the three major exchanges – the LME, CME, and SHFE – we see material geographically focused in the US,” said Albert Mackenzie, a copper analyst at Benchmark.

Of the 994kt of global visible inventory, 800kt is in the US, as assessed by Benchmark’s Copper Service.

“What goes up must come down though, and this material has not been turned into anything yet, so the material could once again become part of price formation,” Mackenzie said. “The whole picture hinges on the next tariff update, and if the US makes a move that leads to a reduction in cathode flows to the US the material that has turned the market into an artificial deficit could make the market artificially looser in future.”

In 2026, the apparent deficit after accounting for excess US stocks is a similar size to the deficit seen in 2022. After multiple years of years of actual and apparent deficits, this is combining with other factors to continuously drive copper prices to new highs.

These other factors driving higher prices include AI bullishness, long-term fears about copper supply, and a narrative of supply disruptions for example.

“Beyond that, we seem to see some financial players overspill into metal markets and this is pushing up base metals across the board,” Mackenzie said.

Listen to Benchmark's Copper Weekly podcast for more discussion about the copper market and what drives it.