We explore the efficiency in the oil industry employing a sample of around 300 companies operating in Europe over 2010–2019. We construct efficiency scores by means of DEA non-parametric techniques. Average efficiency in the sample is modest, 0.27, and decreasing over time. We examine the association of efficiency with economic and financial variables. Results suggest that size is closely associated to efficiency. Large (in the top 10th percentile of income) and very small firms are more efficient, ceteris paribus, whereas medium size and small firms exhibit lower levels of efficiency. Firms which have strived more to implement sustainable technologies and cut greenhouse emissions are more efficient too. Increases in employee costs and decreases in financial solvency jeopardize efficiency, which displays a positive correlation with economic activity and oil prices. As a robustness test, we have repeated the exercise by means of the Simar-Wilson methodology, which confirms our main results regarding efficiency levels and trends and correlations with other variables. Our findings suggest that an industry consolidation is foreseeable in the future.
