Copper prices edged lower on Friday, as concerns over China's tightening monetary policy and lacklustre spot market continued to weigh on sentiment, with investors eyeing key inflation and industrial output data due next week. "The market is watching the consumer price index, worried that the December figure might still be quite high, which would increase the pressure on the government to tighten up more," said a Shanghai-based trader, referring to the data from China due next Tuesday.
Shanghai's benchmark third-month futures contract closed down 0.2 percent at 71,150 yuan ($10,769) a tonne, finishing the week up 2.4 percent. Shanghai's aluminium closed down 0.3 percent at 16,815 yuan.