Oil prices tumbled again Wednesday. Concerns about the chances of Britain leaving the European Union, and a surprise jump in US stockpiles were priced into crude.

After touching multi-month highs last week, the commodity tumbled along with equities markets. The US benchmark West Texas Intermediate and Brent saw an average of more than 6 percent dip for each index from their most recent peaks.

The selling pressure built up Tuesday when the International Energy Agency said a gain in global crude demand this year and next would not be enough to consume all the excessive inventories. 

Traders are waiting for the official US stockpiles figures later Wednesday, while the Federal Reserve is also due to conclude a two-day meeting.