Oil extended losses below $60 a barrel amid speculation that OPEC’s biggest members will defend market share against U.S. shale producers. Brent also slid after closing at the lowest price since July 2009. West Texas Intermediate futures fell as much as 1.9 percent in New York and are down almost 10 percent this week. Iraq , the second-largest producer in the Organization of Petroleum Exporting Countries, said its decision to widen a discount for January sales to Asia isn’t proof of a price war. Crude will decline further next week, according to a Bloomberg News survey of analysts and traders. Oil is headed for the 10th weekly drop since October after OPEC decided against reducing its output, even as the highest U.S. production in more than three decades exacerbates a global glut. Saudi Arabia , Iraq and Kuwait, the group’s three biggest members, this month widened discounts on shipments […]