According to the delivery system of Shanghai Futures Exchange, registered copper is divided into two different delivery grades: standard and substitute. The former is standard cathode copper, and the latter includes high purity cathode copper and LME registered cathode copper. Among them, the registered copper that meets the standard of high-purity cathode copper and is recognized by the exchange is delivered at a premium, and the premium range is 1 10 yuan, commonly known as "premium copper"; Other domestic brands and imported LME registered copper are delivered according to the standard level and do not enjoy a premium, so they are used to being called "flat copper". At present, among all registered brands, only the following five brands enjoy premium: Guiye brand of Jiangxi Copper, Tongguan brand of Tongling, Tiefeng brand of Yunnan Copper, Golden Dolphin brand of Jinlong Copper and Ding Tong brand of Zhangjiagang United Copper, among which the first four brands have been registered in LME. Although there are not many high-quality copper brands, they all belong to large domestic copper factories, accounting for more than half of the total domestic output.