Copper ended above $3,800 a tonne in London trading on Thursday, off an earlier record high as the market braced for a possible bout of profit-taking by the end of the current quarter on Friday, dealers said.
"Prices have rallied strongly in recent days in line with the energy price and that will still have a part to play," a dealer said.
"However, there could be some frayed nerves in the market on Friday if any profit-taking trickles into a wave of selling."
Three-months London Metal Exchange (LME) copper traded earlier at a record $3,835 a tonne on LME Select before closing the kerb session at $3,810, up $24.
The cash/threes premium for prompt delivery eased to $163/173 backwardation and TOM/Next traded at $2.75 contango.
Fund investment has poured into commodities in a spillover from a strong rally in oil after supply worries were heightened when hurricanes Katrina and Rita struck the US Gulf coast.
"Further strikes and stock drawdowns would help rebalance the disparities in the copper market, but as things stand at the moment, it looks as though the market is top-heavy," analyst William Adams of BaseMetals.com said.
Copper was also supported by union pessimism about labour talks at major producer Falconbridge's Kidd Creek mine and refinery in northern Ontario.
Kidd Creek is expected produce about 130,000 tonnes of refined copper and about 135,000 tonnes of zinc this year.
Aluminium was at $1,872, up $17, while tin climbed $225 at $6,650.
Zinc was at $1,420, up $8, while lead added $1 to $950.
Nickel was at $13,495/500, up $45.