  This paper analyzes the informational efficiency of oil market during the
last three decades, and examines changes in informational efficiency with major
geopolitical events, such as terrorist attacks, financial crisis and other
important events. The series under study is the daily prices of West Texas
Intermediate (WTI) in USD/BBL, commonly used as a benchmark in oil pricing. The
analysis is performed using information-theory-derived quantifiers, namely
permutation entropy and permutation statistical complexity. These metrics allow
capturing the hidden structure in the market dynamics, and allow discriminating
different degrees of informational efficiency. We find that some geopolitical
events impact on the underlying dynamical structure of the market.
