Another surge in copper stockpiles tracked by the world’s top base-metals bourse is reigniting concerns about demand for the material that’s often viewed by investors as a bellwether for the global economy. A 40% jump in inventories monitored by the London Metal Exchange in just three days comes amid concerns about China’s slowing industrial activity. Prices of copper, referred to as the metal with a Ph.D in economics, are trading near a four-month low.
