Estimating the degree of operating efficiency gains from a potential bank merger and acquisition: A DEA bootstrapped approach

► The degree of operating efficiency gains of potential M&As is modeled. ► We use a bootstrap DEA procedure to calculate potential scale efficiency gains. ► We apply our procedure to the Greek banking sector for the period 2007-2011. ► The Greek fiscal crisis eliminates any potential operating efficiency gains. ► An M&A between efficient banks does not ensure an efficient bank M&A.