This study examines whether diversification is beneficial to commercial banks using data of U.S., Europe and Asia banks from 1997 to 2003. The empirical results suggest that banks perform better if they diversify between interest and non-interest activities, but this effect is not significant when banks diversify within each of these broad sets of activities. Regional results point out the different effects of commercial banks in U.S., Europe and Asia. My results show that banks earn less risk-adjusted returns from commission, fee and trading income. We conclude that increasing non-interest shares is not as good as expected.

Boyd, J. H. and Stanley L. Graham, 1986, “Risk, regulation, and bank holding company expansion into nonbanking,” Federal Reserve Bank of Minneapolis Quarterly Review, pp. 2-17.
Brewer. E, 1989, “Relationship between bank holding company risk and non-bank activity,” Journal of Economics and Business, 4, pp. 337-53.
Canals. J, 1993, “Competitive strategies in European banking,” Oxford University Press, Oxford.
Claessens, S., S. Djankov, J.P.H. Fan and L.H.P. Lang, 1999, “Corporate Diversification in East Asia: The Role of Ultimate Ownership and Group Affiliation,” World Bank Working Paper, 2089; Washington, DC: World Bank.
Demsetz, R. S. and P. E. Strahan, 1997, “Diversification, Size, and Risk at Bank Holding Companies,” Journal of Money, Credit, and Banking, 29, pp. 300-313
DeYoung, R. and K. P. Roland, 2001, “Product Mix and Earnings Volatility at Commercial Banks:Evidence from a Degree of Total Leverage Model,” Journal of Financial Intermediation, 10, pp. 54-84.
DeYoung, R., 2004, “Noninterest Income and Financial Performance at U.S. Commercial Banks,” The Financial Review, 39, pp.101-127
Diaz, B. D., M. G. Olalla, and S. S. Azofra, 2004 “Bank acquisitions and performance: evidence from a panel of European credit entities”, Journal of Economics and Business, 56, pp.377-404.
Kolari, J. W., 2003, “Assessing the Profitability and Riskiness of Small Business Lenders in the Banking Industry,” Working paper, SBA Office of Advocacy.
Kimball R. C., 1997, “Specialization, Risk, and Capital in Banking,” New England Economic Review, pp.51-73
Khanna, T. and K, Palepu, 2000, “Is Group Affiliation Profitable in Emerging Markets? An Analysis of Diversifies Indian Business Groups,” Journal of Finance, 55, pp.867-891.
Kwan, S H. 1998, “Securities Activities by Commercial Banking Firms’ Section 20 Subsidiaries: Risk, Return, and Diversification Benefits,” Proceedings from a Conference on Bank Structure and Competition, pp. 531–552
Kwan S. H. and Elizabeth S. Laderman, 1999, “On the Portfolio Effects of Financial Convergence—A Review of the Literature,” Federal Reserve Bank of San Francisco Economic Review, pp.18-31.
Lang L.H.P., and R.M. Stulz, 1994, “Tobin’s q, Corporate Diversification and Firm Performance,” Journal of Political Economy, 102, pp. 1248-1280
Lins, K. and H. Servaes, 1999, “International Evidence on the value of Corporate Diversification,” Journal of Finance, 54, pp.2215-2239.
Lins, K. and H. Servaes, 2002, “Is Corporate Diversification Beneficial In Emerging Markets?” Financial Management, 31, pp.5-31.
Nash, R. C. and J. F. Sinkey Jr., 1997, “On competition, Risk, and Hidden Assets in the Maeket for Bank Credit Cards,” Journal of Banking and Finance, 21, pp.89-112.
Nash, R. C. and J. F. Sinkey Jr., 1993, “Association the Riskiness and Profitability of Credit-card Banks,” Journal of Financial Services Research, 2. pp. 127-150..
Rosen, Richard J., Peter R. Lloyd-Davies, Myron L. Kwast and David B. Humphrey, 1989, “A Portfolio Analysis of Bank Investment in Real Estate,” Journal of Banking and Finance, 13, pp. 355-366.
Servaes, H., 1996, “The Value of Diversification During the Conglomerate Merger Wave,” Journal of Finance, 51, pp. 1201-1255.
Smith, R., C. Staikouras, and G. Wood, 2003, “ Non-interest income and total income stability,” working paper, Bank of England.
Stiroh. K.J. and A. Rumble, 2003, ”The Dark Side of Diversification for US Bank Holding Companies,” Unpublished paper, Federal Reserve Bank of New York.
Stiroh. K. J., 2004a, “Diversification in Banking: Is Noninterest income the Answer?” Journal of Money, Credit, and Banking, 36, pp. 853-882
Stiroh, K., 2004b, “Do Community Banks Benefit from Diversification?” Journal of Financial Services Research, 25:2/3, pp.135-160.
Templeton, W. K. and J. T. Severiens, 1992 “The Effect of Nonbank Diversification on Bank Holding Companies.” Quarterly Journal of Business and Economics, 31(4), pp. 3-16