Crude oil prices fell for a fourth day on Wednesday, with jittery investors awaiting official U.S. stockpile figures later in the day after less comprehensive industry data showed a surprise build in inventories.
The American Petroleum Institute (API) said crude stockpiles increased by 9.3 million barrels in the week to Oct. 28, more than nine times the amount expected by analysts polled by Reuters.
U.S. West Texas Intermediate (WTI) crude CLc1 was down 28 cents, or 0.6 percent, at $46.39 by 0014 GMT. On Tuesday it fell 19 cents to $46.67.
Brent crude LCOc1 was down 22 cents at $47.92. In the previous session it hit a one-month low at $47.72 before settling down on the day at $48.14.
The API report typically comes a day before official inventory data from the U.S. government's Energy Information Administration (EIA), which is considered more reliable.
The API bases its numbers on voluntary reporting by members, while the EIA uses a bigger sample. If the government data confirms the large build, traders said earlier crude prices are likely to slump.
In the poll carried out by Reuters on Tuesday before the API numbers were released, analysts had expected a build of 1 million barrels.
