The Brent/WTI spread has historically ranged between $4/bbl and $8/bbl, but it can expand or contract based on factors related to U.S. and international supply and demand conditions. For example, the Brent/WTI spread hit nearly $14/bbl in April 2011 when protests sparked market fears of significant oil supply disruptions in the Middle East.

Oil futures fell Wednesday after industry data showed an unexpected rise in U.S. crude inventories ahead of official figures.

U.S. index futures declined in pre-market trading on Wednesday. Investors are focusing on rising 10-year Treasury yields, statements from central bank policymakers, and today’s financial results from major companies.