Crude oil inventories unexpectedly increased by 7.36 million barrels, contributing to a bearish market outlook.
The American Petroleum Institute (API) estimated this large build for the week ending October 10, contrary to analyst forecasts of a 120,000-barrel build.
No supply crunch yet, but underinvestment could lead to one, says Saudi Aramco.
Record US production and IEA warnings of a global supply overhang also add to the bearish outlook.
Author's note: Oil prices drop due to high inventory.