Copper scales highest since mid-May as US inventory builds up amid tariff uncertainty

The premium for the LME cash copper contract over the three-month contract CMCU0-3 widened to as much as $117.50 a ton on Thursday, signalling tightening near-term supply.

Copper has been drawn towards the United States for months as uncertainty over potential import tariffs keeps prices on the U.S. COMEX exchange above the London benchmark.

The front-month COMEX copper contract HGc1 touched a record high on Wednesday, maintaining a wide premium over LME copper.

COMEX inventories HG-STX-COMEX increased to 720,140 short tons (653,300 tons) as of Wednesday. Stocks held in warehouses monitored by the LME MCUSTX-TOTAL and the Shanghai Futures Exchange CU-STX-SGH, meanwhile, have continued to decline.