Copper futures fell at the open with speculative sellers taking their cue from a slide in London copper and deciding to take fast profits after the steep run-up a day earlier, traders said.
"It's just a little bit of a retracement. It's been up the last few days, so it's pretty much just some light profit taking," said one copper broker, noting that volumes remained light as they have been for much of a week. "We've been bouncing around for the last few weeks.
We have a little breakout, then it comes back down. It comes off and then we rally again. It's just a normal day with very light volume," another trader said.
At the New York Mercantile Exchange's COMEX division, benchmark December copper slipped 2.30 cents to $1.6210 a lb., in a $1.62 to $1.6445 a lb range.
Spot September copper lost 1.60 cents to $1.7030 a lb., in a $1.7010 to $1.7155 a lb. trading band. COMEX copper volume was estimated at a light 2,000 lots.
Traders pointed out that heavy selling for much of last week took a chunk out of copper's open interest, allowing some players to add to long positions on Monday.