In New York, the most active May COMEX contract rose 3.25 cents to settle at $3.9215 per lb, after dealing between $3.8670 and $3.9575. Copper has climbed around 13 percent so far this year, largely in line with gains in the Shanghai Composite Index.
"The liquidity injection is playing a much bigger role in driving metals prices at the moment than the fundamentals," said Gianclaudio Torlizzi, a partner at T-Commodity.