added in 2002, Ekofisk crude oil was added in 2007, and Troll crude oil was added in 2018 to Brent crude oil pricing basket. Moreover, the different grades in the "Brent basket" are priced different. For example, Ekofisk, Oseberg, and Troll crude oil grades have a quality premium over Brent crude oil grades, while Forties have a price discount for high sulphur content. Brent prices usually reflect the cheapest or the most competitive physical crude oil in the above basket, which means that Brent prices usually reflect prices for Forties crude oil. These quality changes to Brent Crude oil directly affect the premium or discount between what refiners would pay for WTI and Brent crude oil. See also Dubai Mercantile Exchange List of crude oil products Petrobourse Petroeuro Petroleum classification References External links U.S. Energy Information Administration – Part of the U.S. Department of Energy, official source of price and other statistical information West Texas Intermediate (WTI) (WTISPLC), time series from 1946 at the St. Louis Fed Benchmark crude oils Economy of Texas Petroleum in the United States