The info on Cit’s outlook comes via a gated Reuters report. In brief:

Citi predicts that the U.S. will implement a 25% tariff on copper imports by the fourth quarter of 2025, following an executive order by President Donald Trump to investigate copper trade. The order aims to bolster domestic copper production, which is crucial for electric vehicles, military equipment, and infrastructure.

In anticipation, Citi expects the one-year forward COMEX copper premium over LME to reflect an eventual 25% tariff
Before tariffs take effect, U.S. buyers may stockpile copper, temporarily driving up prices, but this could reverse once the duties are imposed.

Citi also warns that tariffs may be enforced earlier through reciprocal trade measures or country-specific duties, such as those imposed on Canada and Mexico.

Reciprocal tariffs on copper imports could arrive as early as Q2 2025 as part of broader trade policies.

The investigation covers multiple copper forms, including raw ore, refined metal, alloys, scrap, and finished products. While the official review period extends until November 2025, past cases on steel and aluminum suggest the process might accelerate. Citi expects the tariff to be implemented no earlier than May 2025.

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Earlier:

US copper tariffs are a bizarre strategy but highlight a real shortage