Copper ended lower in US and Asian trading on Tuesday in thin year-end dealings as the London markets remained closed for Christmas. US copper futures' most-active contract, March, settled down 6.05 cents, or 1.7 percent, at $3.4090 per lb on New York's COMEX. Trade was razor-thin, with volume less than a quarter of the 30-day average.
Most commodities rose in Tuesday's trade, with oil surging on concerns over threats to crude supplies from Iran and grains and soybean prices rallying on weather woes in Argentina.
Copper was subdued despite a strong reading for US consumer confidence in December, which further bolstered the outlook for recovery in the world's largest economy.
"I'm guessing today's weaker metals prices have more to do with year-end book squaring activity that could be leading to more selling than buying," said Michael Smith, president of T & K Futures and Options Inc in Port St. Lucie, Florida. "Also, volumes are so thin that any move in whatever direction seems exaggerated."
Copper prices are poised to finish the year about 20 percent or more lower, with the bulk of the declines occurring during the third quarter on heightened worries about the eurozone debt crisis.