Spot copper in Shanghai was quoted at a discount of RMB 0-20/mt and premium of RMB 0-80/mt over SHFE 1307 copper contract prices on Thursday. Traded prices for standard-quality copper were between RMB 50,620-50,700/mt, and RMB 50,660-50,820/mt for high-quality copper. SHFE copper jumped almost 4%. Spot copper supply fell, allowing cargo holders to hold prices firm. Most holders of standard-quality copper refused to sell at discount in the morning. However, premium of high-quality copper fell to RMB 50-60/mt and imported standard-quality copper was sold at discount towards mid-day as the price gap between SHFE 1307 and 1308 copper contract expanded. Downstream producers refrained from buying once copper prices rose above RMB 50,000/mt. With SHFE copper extending increases in the afternoon, spot copper was quoted at discounts of RMB 0-100/mt, and traded prices grew to RMB 50,950-51,250/mt. Some traders started purchasing spot copper for arbitrage, but downstream buyers rarely purchased.