Spot copper in Shanghai was quoted at a premium of RMB 150-250/mt over SHFE 1305 copper contract on Thursday. Traded prices for standard-quality copper were between RMB 51,400-51,850/mt, and RMB 51,450-52,000/mt for high-quality copper. SHFE 1308 copper contract rose after a high opening, leaving little room for arbitrage. Spot copper supply was stable, while downstream producers began to build up stocks for the upcoming Chinese May Day holiday. Cargo holders had more negotiation power over pricing. Spot copper supply continued to reduce in the afternoon. Some traders held prices high, and premiums were between RMB 170-270/mt. Traded prices remained little changed from the morning session but transactions were few.