Prices for crude oil benchmarks WTI and Brent have historically been related. In general WTI light sweet crude oil sold at a 5% premium to Brent crude oil between 1994 and 2010. However, this relationship between WTI and Brent crude oil totally collapsed in 2011. Brent crude oil sold at an average premium of $13/bbl in 1H11, or 13%, reaching $23/bbl in mid-June.