When OPEC announced production cuts last year, the most reliable indicator of oil-market supply started signaling a shortage ahead. Now it’s pointing the other way. In the weeks after OPEC’s Nov. 30 agreement, shorter-term oil prices began to strengthen versus longer-term contracts amid expectations the group’s output cuts would cause a shortfall this year. That trend is reversing on growing concern the curbs aren’t enough to clear the surplus in world oil inventories. Oil prices have slumped below $50 a barrel for the first time this year as record crude stockpiles and rebounding production in the U.S. suggest that the curbs by the Organization of Petroleum Exporting Countries and Russia aren’t working fast enough. In January, front-month Brent crude futures narrowed their discount — known as contango — against contracts for the following year on expectations the supply curbs would succeed. By Feb. 21, the front-month had developed a […]