Opec is struggling to maintain a semblance of discipline among its members, with output nearly 1mn b/d above target in July and Ecuador openly saying it won’t adhere to restrictions.

Opec crude output in July was 660,000 b/d below the November 2016 peak, but US crude output alone has grown 562,000 b/d over the same period (758,000 b/d including NGLs). The resultant dampening of initial price gains is eroding Opec discipline.

Opec Secretary General Mohammed Barkindo continues to put a...