The article explores what affects the price difference between two types of oil, West Texas Intermediate and Brent, from 1995 to 2019. They found significant changes in 2010, 2005, and 2012. Factors like oil inventories, trading in oil markets, shipping costs, and stock market activity in the US and Europe influence the price spread. Since 2010, trading activity, open interest, and shipping costs have become more important in determining the price difference.