This paper demonstrates the importance of using a flexible cost function specification when analyzing economies of scale and estimating the cost effect of banking mergers. The inflexibility of the translog cost function is illustrated and results are compared to more flexible spline and Fourier cost functions. Using these different approaches we predict the ex ante effect on average cost from mergers over 1987–1998 using a balanced panel of 130 Norwegian banks. On average mergers are predicted to lower costs. Predictions using the Fourier or spline approach are in overall agreement with computed actual average merger-cost changes ex post. Cost effects of electronic payments are also estimated and exceed cost reductions associated with mergers.

This paper studies strategies pursued by banks in order to differentiate their services and soften competition. More specifically we analyze whether bank's ability to avoid losses, its capital ratio, or bank size can be used as strategic variables to make banks different and increase the interest rates banks can charge their borrowers in equilibrium. Using a panel of data covering Norwegian banks between 1993 and 1998 we find empirical support that the ability to avoid losses, measured by the ratio of loss provisions, may act as such a strategic variable. A likely interpretation is that borrowers use high-quality low-loss banks to signal their creditworthiness to other stakeholders. This supports the hypothesis that high-quality banks serve as certifiers for their borrowers. Furthermore, this suggests that not only lenders and supervisors but also borrowers may discipline banks to avoid losses.