Question: why wti is cheaper than brent?
Answer: WTI oil has a higher API and lower sulfur content then Brent oil. Thus makes WTI easier to refine and it is also good for environment point of view. Therefore it should be costlier then Brent, As it was before 2010 but after 2010 price difference between WTI and Brent changed dramatically. ... Thus made WTI more costlier.