Why Is the Spread Refined-Crude Oil Price Increasing Strongly in the Post-COVID Period in the US? A Fractional Integration and Cointegration Analysis

This paper aims to study the recent increase in the spread of refined-crude petroleum prices in the US. We analyze the evolution of crude oil prices, refining costs, distribution costs, and taxes, comparing the pre and post covid periods. Fractional integration and cointegration methodologies are used to analyze the degree of persistence and to understand the long-term behavior between time series. Our results indicate that the spread refined-crude oil price has partially increased because of natural gas prices rising and has mainly grown due to the industrial supply bottleneck. Extraordinary measures must be taken to recover the original trend