US copper futures rise as tariff worries mount

LONDON, Feb 27 (Reuters): US copper prices extended gains on Thursday, outperforming the London benchmark as worries about US import tariff plans inflated the regional premium and concerns about economic growth for the wider market.

The most active May copper futures on the US Comex exchange rose 1 per cent to $4.634 per lb. Three-month copper on the London Metal Exchange lost 0.5 per cent to $9,415 a metric ton in official open-outcry trading.

"Trade discussions are adding layers of uncertainty to base metal markets," said WisdomTree commodity strategist Nitesh Shah.

China, the world's top metals consumer, on Thursday urged the US to halt an investigation into potential new tariffs on copper imports, vowing to retaliate if Chinese entities become caught up in the levies.

US President Donald Trump clouded the outlook for looming levies on top trading partners Canada and Mexico on Wednesday by signalling that they would take effect on April 2 instead of the previously stated deadline of March 4.

But a White House official said levies on Mexican and Canadian goods remained in effect "as of this moment", stirring further uncertainty about US trade policy. Trump also floated the idea on Wednesday of a 25 per cent "reciprocal" tariff on European cars and other goods.

The Comex copper premium over the LME contract widened to $764 a ton from $633 on Wednesday.