In this article, the authors measure the effect of non-traditional activities on both bank cost and profit efficiency. The article provided the first international study about the relevance of these activities in the estimation of banks efficiency. The estimation is made using the stochastic frontier approach on a sample of banks covering all the geographical regions. The estimation is well documented in the methodology and results section, but there is a problem with the article structure.

Weaknesses

1. The authors are stating that they used for the study a sample of publicly quoted commercial banks from 87 countries around the world. But in Appendix B the total number of countries displayed is 88. This difference need to be clarified.
2. The different sections in this study are not well organized. The authors detailed the method and the results, but there is no state of the art section in this article which poses a problem in the results interpretation. The authors made a quick state of the art in the introduction section and focused on the methodology they used. They missed some important references like other articles studying the effect of non-traditional activities and focusing on banks in a specific region like : Sturm, J.E. and Williams, B., 2004. Foreign bank entry, deregulation and bank efficiency: Lessons from the Australian experience. Journal of Banking & Finance, 28(7), pp.1775-1799.
3. The authors are giving the results interpretations in the results section. They should have added a discussion section and move those interpretations to this section.

Overall, despite the problem in the article structure and the absence of the state of the art section this article provides the first international study about the effect of non-traditional activities on banks' efficiency and give a cross-country comparison based on the levels of economic development and geographical regions.