Copper ended lower on Thursday, unable to build on the previous session's sharp rally, as investors sided with caution after another round of weak data suggested the US economic recovery could be stalling.
One day after the metal posted its biggest gain in two months, copper prices fell in tandem with other economically-sensitive commodities like crude oil, after discouraging US housing and factory data pointed to less economic strength than previously thought.
"These assets are linked very closely to macro-economic demand and performance ... the data are likely weighing on the markets," said Jason Schenker, head of Prestige Economics in Texas.
In New York, the COMEX July contract fell 5.25 cents to settle at $4.0525 per lb.
On Wednesday, prices of the metal rallied some 3 percent in their biggest daily gain since March 17. "It's a little bit disappointing there hasn't been much follow-through (from Wednesday's rally)," Standard Chartered analyst Daniel Smith said.
Copper's losses accelerated after data showed a slowdown in manufacturing growth in the US Mid-Atlantic region and an unexpected dip in existing home sales in APRIL.