Last night, the highly followed Shanghai Index (China) rallied sharply higher. The Shanghai Index finished higher by 1.35 percent. Usually, when the Shanghai Index has rallied so sharply in the past copper will generally trade higher regardless of move in the U.S. Dollar Index. Today, that relationship is not occurring as copper is declining. Many traders and investors will follow copper very closely as a sign of economic expansion. Some leading copper stocks that are trading lower this morning are Freeport McMoRan Copper & Gold Inc.(NYSE:FCX), and Southern Copper Corp.(NYSE:SCCO). Traders can get a good gauge of copper by following the iPath DJ-UBS Copper TR Sub-Idx ETN (NYSE:JJC).