Evolution of the World Crude Oil Market Integration : A Graph Theory Analysis

This paper investigates the evolution of the world crude oil market and the pricing power for major oil-producing and oil-consuming countries using graph theory. A minimal spanning tree for the world crude oil market is constructed and some empirical results are given. The integration of the world crude oil market is verified. Furthermore, the world crude oil market is characterised as a geographical and organisational structure. The crude oil markets of adjacent countries or regions tend to link together, while OPEC is well-integrated. We also found that the links in the South and North American region and the African region are relatively stable. The crude oil markets in the U.S., Angola and Saudi Arabia take up the core, with a higher ‘betweenness centrality' and lower ‘farness', whereas the markets in the East and Southeast Asian countries are on the fringe. Finally, the degree of globalisation for the world crude oil market is becoming further entrenched, verified by a decreasing normalised tree length; hence, its systemic risk may increase due to the future uncertainty of world politics