Oil headed for its biggest monthly drop this year on speculation that increased OPEC supplies and threats to demand in China will prolong a global glut. Futures slid as much as 1.5 percent in New York and are down 19 percent in July. U.S. crude stockpiles are almost 100 million barrels above the five-year seasonal average, while exports from southern Iraq rose to a record this month. Producers from BP Plc to Royal Dutch Shell Plc have started a new round of cost cutting as prices decline. Oil’s worst month since December paces a slump across raw materials amid expanding surpluses and concern slower economic growth in China will crimp demand. Commodities also dropped as the dollar gained on signs that the Federal Reserve may increase rates. Sanctions on oil exports from Iran, holder of the world’s fourth-biggest crude reserves, may be lifted following a nuclear accord on July […]