West Texas Intermediate futures for September delivery plunged to $40.90 (-0.90%), while Brent crude fell to $46.85 (-0.66%) after the U.S. Energy Information Administration reported a surprise increase of 2.6 million barrels in crude supplies for the week ended August 14. Gasoline supplies fell 2.7 million barrels, while distillate stockpiles rose by 600,000 barrels. US crude production fell 47,000 barrels to 9.348 million barrels a day last week. However U.S. output is still likely to be the highest since 1972.

The EIA also lowered its price expectations for West Texas Intermediate (WTI) by $6 per barrel to $49 for 2015, and by $8 per barrel to $54 in 2016. Revisions were based on concerns over economic growth in emerging markets, ample supply, rising inventories worldwide and prospects of additional exports from Iran.