Copper prices have posted a large price range at the start of the new trading week, with many traders pointing towards concerns that China might begin to export copper stocks as an early indication of slack demand inside China. The copper market may have found some support from predictions by the International Copper Study Group of a global copper supply deficit of 237,000 tons this year. However, any positive impact from that news may have been partially offset by a longer term prediction of a 360,000 ton global supply surplus in 2013. A partial holiday in Asia reduced the flow of fundamental copper news overnight, which in turn could leave the copper market putting additional focus on US economic data due out later this morning. With some traders attributing the late April rally in copper prices to fresh hopes of US easing, softer than expected US data could help the market to recover early losses.