Cost metafrontier approach for measuring the Malmquist productivity index: An example of bank groups formed after the financial reform in Taiwan

This study attempts to provide a framework under the variable returns to scale hypothesis to account for the effect of the cost scale efficiency change in the decomposition of the cost metafrontier Malmquist productivity index (CMMPI). In addition, the meta‐cost efficiency and cost frontier gap between subordinate banks of financial holding companies (FHC) and independent banks are also examined. A total of 34 banks in Taiwan are empirically analysed from 1999 to 2012. The results indicate that the meta‐cost efficiency, meta‐technical efficiency and meta‐allocative efficiency scores of subordinate banks of FHC are better than those of independent banks. The banking industry in Taiwan is found to have an improvement in cost metafrontier Malmquist productivity. The subordinate banks of FHC are also found to exhibit positive CMMPI and decomposition components, but do not achieve a significant improvement except in the case of the technical gap ratio change. The empirical results recommend that Taiwanese banks place more policy focus on the issue of scale adjustment, which should be beneficial. Based on the CMMPI decomposed results, we can gain further understanding of the growth path to enhance operational performance.