COMEX copper futures ended at one-week lows Thursday on stop loss selling due to fears of an inventory build, while traders also squared up positions in financial markets ahead of Friday's US employment data.
Analysts said a 6 percent jump in London Metal Exchange copper stocks on Wednesday, and jitters over more rises down the line, were pressuring copper prices after Tuesday's rally on a mine strike in Peru.
Copper futures on the COMEX division of the New York Mercantile Exchange will close early at 12:05 pm EDT on Friday and remain shut Monday for the US Labour Day holiday.
The active December contract settled at $1.2480 a lb, off 2.90 cents or 2.27 percent, within a range of $1.2770 to $1.2380, its lowest level since August 26. Spot September lost 2.75 to $1.2475. Back months fell 2.70-2.90 cents.