SHANGHAI, May 25 (SMM) – Spot copper premiums were quoted between positive RMB 220-300/mt in Shanghai in the morning business. Traded prices for standard-quality copper were between RMB 55,820-55,900/mt, and RMB 55,870-55,980/mt for high-quality copper. SHFE copper prices retreated after starting higher, propelling cargo-holders in spot markets to sell. Spot copper supply increased as a result, leading spot copper premiums to narrow. Some traders were pessimistic about future copper prices and thus hedged against price volatilities. However, downstream producers stuck to the sidelines, leaving market activity lackluster.