In this paper, we show the importance of accounting for heterogeneity among sample firms in stochastic frontier analysis. For a fairly homogenous sample of German savings and cooperative banks, we analyze how alternative theoretical assumptions regarding the nature of heterogeneity can be...

Theory of financial intermediation gives contradicting answers to the question whether banks should diversify or focus their loan portfolios. Our aim is to find out which of the two strategies is predominant in the German banking market. To this end we measure diversification for all German...