SHANGHAI, Apr. 22 (SMM) – In the Shanghai physical market, copper was offered Tuesday at a premium of RMB 580-750/mt over the nearby SHFE contract. Traded prices were RMB 47,880-48,040/mt for standard-quality copper and RMB 47,980-48,300/mt for high-quality copper. After SHFE copper prices fell back from highs and trading resumed on the London Metal Exchange, the SHFE/LME copper arbitrage ratio improved slightly, allowing importers to move goods in large amounts. In addition, some traders with goods from long-term contracts ramped up deliveries to raise cash at high premiums, which added to oversupply pressure and in turn sent premiums down sharply. Standard-quality copper and hydro-copper brands both gained favor with market participants, with their prices drawing close to prices for high-quality copper. Middlemen began staying on the sidelines, while downstream producers stepped up bargain-hunting after their buying interest were restrained by high premiums on Monday.