“…This applies to the academic literature, where most analyses are based on comparisons of incumbents' efficiency (De Borger, 1992;Cantos & Maudos, 2001;Friebel et al, 2010), on national approaches (Vierth, 2011;Laisi et al, 2012;Woodburn, 2014) or on aggregate approaches for the European market Gevaers et al, 2015). It also applies to the European Commission, whose market monitoring addresses only the industry level and uses aggregate data.…”