Shanghai copper futures turned positive on Friday after data showed a jump in imports of the metal into China, the world's top consumer of the commodity. China's unwrought copper imports rose by more than 40 percent in November from the previous month, in a sign that winter production restrictions at the world's top copper consuming country are driving up shipments of overseas metal.
"It could be buying delayed by China's holidays in October and that combined with the arbitrage window being open has pushed up ... imports," said Lachlan Shaw, an analyst for UBS. "Concerns about China's pollution controls impacting supply could also be encouraging some stockpiling," he said.
The most-traded copper contract on the Shanghai Futures Exchange ended up 0.51 percent at 51,700 yuan ($7,813.92) a tonne. "The rise backs up our view that a tightening copper-concentrate market is pushing many buyers into the refined metal market to satisfy its copper units," said ANZ Bank commodities analyst Daniel Hynes.