Driven Determinants to Indonesia Sharia Commercial Banks' Performance: The Important Role of Diversification Strategy


  • Sobar M. Johari Universitas Muhammadiyah Yogyakarta Author
  • Wing-Keung Wong Asia University Corresponding Author
  • Ammelia Rizza Fitri Ayu L.C. Gadjah Mada University Author



Net Operating Margin, Diversification, Islamic Commercial Banks, Endogenous Switching Regression


  • Purpose: This study aims to analyze the role of income diversification and asset diversification on the sensitivity of the determinant of the Net Operating Margin (NOM) of Islamic Commercial Banks (ICB) in Indonesia.
  • Design/Methodology/Approach: By using the technique of the endogenous switching regression analysis, the researcher assumes that the influence of the NOM’s determinant can be different when the bank has high or low diversification. By dividing the two regimes on the diversification variable, the researcher can determine which regime the NOM will be more sensitive to the fluctuation of the NOM’s determinant.
  • Findings: The results of this study indicate that operational costs have an essential role in determining the level of NOM. NOM tends to be more sensitive to its determinants when the ICB is not functionally diversified compared to ICB, which diversifies its income and assets. This study also found that a large ICB has a greater probability of diversifying high income than a small ICB.
  • Research limitations/implications: This study has limitations, among others, this study only covers Islamic commercial banks in Indonesia for a certain period due to data availability. This study also only focuses on the company's internal variables, so that future researchers can use a wider range of data and external variables to enrich the diversification effect.
  • Practical implications: This study has several important policy implications for banks regarding a detailed description of the benefits of asset diversification and income diversification. In addition, the results of this study can also be used as a reference for policy makers, especially the government if they want to build an ideal NOM ratio for the Islamic banking industry by establishing regulations related to the efficiency level of Islamic banking in carrying out financial intermediation activities.
  • Originality/value: This study contributes to the recent literature that presents the role of income diversification and asset diversification on the sensitivity of the determinants of Net Operating Margin (NOM) in Islamic Commercial Banks (ICB) in Indonesia.


Abdul Majid, M., Falahaty, M., Jusoh, M. (2017). Performance of Islamic and Conventional Banks: A Meta-Frontier Approach. Research in International Business and Finance 42, 1327-1335.

Abedifar, P., Molyneux, P., & Tarazi, A. (2013), 'Risk in Islamic Banking', Review of Finance, 17(6), 2035-2096.doi:10.1093/rof/rfs041

Alqahtani, F., Mayes, D.G., Brown, K. (2017). Islamic Bank Efficiency Compared to Conventional Banks During the Global Crisis in the GCC Region. Journal of International Financial Markets, Institutions and Money, 51, 58-74.

Ascarya, A., & Yumanita, D. (2010). The Determinants of Net Interest Margin in Conventional and Islamic Banks in Indonesia. Paper presented at the International Conference on Eurasian Economies 2010.

Baele, L., De Jonghe, O., & Vander Vennet, R. (2007), 'Does the Stock Market Value Bank Diversification?', Journal of Banking & Finance,31(7),1999-2023. doi:10.1016/j.jbankfin.2006.08.003

Berger, A. N., Bonime, S. D., Covitz, D. M., & Hancock, D. (2000), 'Why Are Bank Profits So Persistent? The Roles of Product Market Competition, Informational Opacity, and Regional/Macroeconomic Shocks', Journal of Banking & Finance, 24(7), 1203-1235. doi:10.1016/s0378-4266(99)00124-7

Birchwood, A., Brei, M., & Noel, D. M. (2017), 'Interest margins and bank regulation in Central America and the Caribbean', Journal of Banking & Finance, 85, 56-68. doi:10.1016/j.jbankfin.2017.08.003

Brock, P. L., & Rojas Suarez, L. (2000), 'Understanding the behavior of bank spreads in Latin America', Journal of Development Economics, 63(1), 113-134. doi:10.1016/s0304-3878(00)00102-4

Carbó-Valverde, S., Rodríguez-Fernández, F., & Udell, G. F. (2009), 'Bank Market Power and Sme Financing Constraints', Review of Finance, 13(2), 309-340. doi:10.1093/rof/rfp003

Carbó Valverde, S., & Rodríguez Fernández, F. (2007), 'The Determinants of Bank Margins in European Banking', Journal of Banking & Finance, 31(7), 2043-2063. doi:10.1016/j.jbankfin.2006.06.017

Chatti, M. A., Kablan, S., & Yousfi, O. (2013), 'Are Islamic Banks Sufficiently Diversified ? : An Empirical Analysis of Eight Islamic Banks in Malaysia', Islamic Economic Studies, 21(2), 23-54. doi:10.12816/0001557

Chen, N., Liang, H.-Y., & Yu, M.-T. (2018), 'Asset diversification and bank performance: Evidence from three Asian countries with a dual banking system', Pacific-Basin Finance Journal, 52, 40-53. doi:10.1016/j.pacfin.2018.02.007

Chong, B. S., & Liu, M.-H. (2009), 'Islamic banking: Interest-free or interest-based?', Pacific-Basin Finance Journal, 17(1), 125-144. doi:10.1016/j.pacfin.2007.12.003

Demirguc-Kunt, A., & Huizinga, H. (1999), 'Determinants of Commercial Bank Interest Margins and Profitability: Some International Evidence', The World Bank Economic Review, 13(2), 379-408. doi:10.1093/wber/13.2.379

Demirguc-Kunt, A., Laeven, L., & Levine, R. (2004), 'Regulations, Market Structure, Institutions, and the Cost of Financial Intermediation', Journal of Money, Credit, and Banking, 36(3b), 593-622. doi:10.1353/mcb.2004.0045

DeYoung, R., & Roland, K. P. (2001), 'Product Mix and Earnings Volatility at Commercial Banks: Evidence from a Degree of Total Leverage Model', Journal of Financial Intermediation, 10(1), 54-84. doi:10.1006/jfin.2000.0305

Dominic Gasbarro & Wing-Keung Wong & J. Kenton Zumwalt, 2012. "Stochastic Dominance And Behavior Towards Risk: The Market For Ishares," Annals of Financial Economics (AFE), World Scientific Publishing Co. Pte. Ltd., vol. 7(01), pages 1-20.

Do Thi Thanh Nhan & Kim-Hung Pho & Dang Thi Van Anh & Michael McAleer, 2021. "The Safety of Banks in Vietnam Using CAMEL," Advances in Decision Sciences, Asia University, Taiwan, vol. 25(2), pages 158-192, June.

Do Thi Thanh Nhan & Kim-Hung Pho & Dang Thi Van Anh & Michael Mcaleer, 2021. "Evaluating The Efficiency Of Vietnam Banks Using Data Envelopment Analysis," Annals of Financial Economics (AFE), World Scientific Publishing Co. Pte. Ltd., vol. 16(02), pages 1-17, June.

Duc Hong Vo & Quang Van Tuan & Trung Vu-Thanh Pham, 2019. "Sectoral Risks in Vietnam and Malaysia A Comparative Analysis," Advances in Decision Sciences, Asia University, Taiwan, vol. 23(1), pages 62-87, March.

Elsas, R., Hackethal, A., & Holzhäuser, M. (2010), 'The Anatomy of Bank Diversification', Journal of Banking & Finance, 34(6), 1274-1287. doi:10.1016/j.jbankfin.2009.11.024

Fungáčová, Z., & Poghosyan, T. (2011), 'Determinants of bank interest margins in Russia: Does bank ownership matter?', Economic Systems, 35(4), 481-495. doi:10.1016/j.ecosys.2010.11.007

Gambacorta, L., & Shin, H. S. (2018), 'Why bank capital matters for monetary policy', Journal of Financial Intermediation, 35, 17-29. doi:10.1016/j.jfi.2016.09.005

Gamra, S. B., & Plihon, D. (2010), 'Who benefits from financial liberalization? Evidence from advanced and emerging market economies', Macroeconomics and Finance in Emerging Market Economies, 3(1), 53-74. doi:10.1080/17520840903076465

Gertner, R., & Scharfstein, D. (1991), 'A Theory of Workouts and the Effects of Reorganization Law', The Journal of Finance, 46(4), 1189-1222. doi:10.1111/j.1540-6261.1991.tb04615.x

Ho, T. S. Y., & Saunders, A. (1981), 'The Determinants of Bank Interest Margins: Theory and Empirical Evidence', The Journal of Financial and Quantitative Analysis, 16(4), 581. doi:10.2307/2330377

Hu, X., & Schiantarelli, F. (1998), 'Investment And Capital Market Imperfections: A Switching Regression Approach Using U.S. Firm Panel Data', The Review of Economics and Statistics, 80(3), 466-479.

Ibrahim, M. H., & Law, S. H. (2020). Financial intermediation costs in a dual banking system: The role of islamic banking. Buletin Ekonomi Moneter Dan Perbankan, 22, 529–550.

Jensen, M. (1986), 'Agency Costs of Free Cash Flow, Corporate Finance, and Takeovers', American Economic Review, 76(2), 323-329. doi:10.1017/cbo9780511609435.005

Johari, M. (2014). Analisis Financial Crunch Pada Industri Perbankan Syariah Saat Krisis Keuangan Global 2008. Afkaruna: Indonesian Interdisciplinary Journal of Islamic Studies, 10(1), 59-67. doi:

Johari, S. M., & Ramadhania, S. A. (2019). Analisis Tingkat Literasi Keuangan Syariah Pada Penyandang Disabilitas di Daerah Istimewa Yogyakarta. Al-Urban: Jurnal Ekonomi Syariah Dan Filantropi Islam, 3(1), 24-41.

Johnes, J., Izzeldin, M., Pappas, V. (2014). A Comparison of Performance of Islamic and Conventional Banks 2004-2009. Journal of Economic Behaviour & Organization, 103, s93-s107.

Karakaya, A., & Er, B. (2012), 'Noninterest (Nonprofit) Income and Financial Performance at Turkish Commercial and Participation Banks', International Business Research, 6(1). doi:10.5539/ibr.v6n1p106

Karas, A., Pyle, W., & Schoors, K. (2013), 'Deposit Insurance, Banking Crises, and Market Discipline: Evidence from a Natural Experiment on Deposit Flows and Rates', Journal of Money, Credit and Banking, 45(1), 179-200. doi:10.1111/j.1538-4616.2012.00566.x

Khan, F. (2010), 'How ‘Islamic’ is Islamic Banking?', Journal of Economic Behavior & Organization, 76(3), 805-820. doi:10.1016/j.jebo.2010.09.015

Kofi Adjei-Frimpong & Christopher Gan & Baiding Hu, 2013. "Efficiency And Competition In The Ghanaian Banking Industry: A Panel Granger Causality Approach," Annals of Financial Economics (AFE), World Scientific Publishing Co. Pte. Ltd., vol. 8(01), pages 1-16.

Laeven, L., & Levine, R. (2007), 'Is There a Diversification Discount in Financial Conglomerates?', Journal of Financial Economics, 85(2), 331-367. doi:10.1016/j.jfineco.2005.06.001

Lee, S. P., & Isa, M. (2017), 'Determinants of bank margins in a dual banking system', Managerial Finance, 43(6), 630-645. doi:10.1108/mf-07-2016-0189

Le Ngoc Thuy Trang & Do Thi Thanh Nhan & Nguyen Thi Nhu Hao & Wing-Keung Wong, 2021. "Does Bank Liquidity Risk Lead To Bank'S Operational Efficiency? A Study In Vietnam,"Advances in Decision Sciences, Asia University, Taiwan, vol. 25(4), pages 46-88, December.

Lepetit, L., Nys, E., Rous, P., & Tarazi, A. (2008), 'Bank Income Structure and Risk: An Empirical Analysis of European Banks', Journal of Banking & Finance, 32(8), 1452-1467. doi:10.1016/j.jbankfin.2007.12.002

Lin, J.-R., Chung, H., Hsieh, M.-H., & Wu, S. (2012), 'The determinants of interest margins and their effect on bank diversification: Evidence from Asian banks', Journal of Financial Stability, 8(2), 96-106. doi:10.1016/j.jfs.2011.08.001

López-Espinosa, G., Moreno, A., & Pérez de Gracia, F. (2011), 'Banks’ Net Interest Margin in the 2000s: A Macro-Accounting international perspective', Journal of International Money and Finance, 30(6), 1214-1233. doi:10.1016/j.jimonfin.2011.06.001

Magalhães, R., & Al‐Saad, S. (2013), 'Corporate governance in Islamic financial institutions: the issues surrounding unrestricted investment account holders', Corporate Governance: The international journal of business in society, 13(1), 39-57. doi:10.1108/14720701311302404

Moawia Alghalith & Xu Guo & Wing-Keung Wong & Lixing Zhu, 2016. "A General Optimal Investment Model In The Presence Of Background Risk," Annals of Financial Economics (AFE), World Scientific Publishing Co. Pte. Ltd., vol. 11(01), pages 1-8, March.

Maudos, J. n., & Fernández de Guevara, J. (2004), 'Factors explaining the interest margin in the banking sectors of the European Union', Journal of Banking & Finance, 28(9), 2259-2281. doi:10.1016/j.jbankfin.2003.09.004

Moudud-Ul-Huq, S., Ashraf, B. N., Gupta, A. D., & Zheng, C. (2018), 'Does bank diversification heterogeneously affect performance and risk-taking in ASEAN emerging economies?', Research in International Business and Finance, 46, 342-362. doi:10.1016/j.ribaf.2018.04.007

Naceur, S. B., & Omran, M. (2011), 'The Effects of Bank Regulations, Competition, and Financial Reforms on Banks' Performance', Emerging Markets Review, 12(1), 1-20. doi:10.1016/j.ememar.2010.08.002

Nguyen Duy Suu & Thu-Quang Luu & Kim-Hung Pho & Michael McAleer, 2020. "Net Interest Marginof Commercial Banks in Vietnam,"Advances in Decision Sciences, Asia University, Taiwan, vol. 24(1), pages 1-27, March.

Nguyen, J. (2012), 'The relationship between net interest margin and noninterest income using a system estimation approach', Journal of Banking & Finance, 36(9), 2429-2437. doi:10.1016/j.jbankfin.2012.04.017

Olson, D., & Zoubi, T. A. (2008), 'Using accounting ratios to distinguish between Islamic and conventional banks in the GCC region', The International Journal of Accounting, 43(1), 45-65. doi:10.1016/j.intacc.2008.01.003

Perera, S., Skully, M., & Wickramanayake, J. (2010), 'Bank market concentration and interest spreads: South Asian evidence', International Journal of Emerging Markets, 5(1), 23-37. doi:10.1108/17468801011018257

Richard Lu & Chen-Chen Yang & Wing-Keung Wong, 2018. "Time Diversification: Perspectives From The Economic Index Of Riskiness," Annals of Financial Economics (AFE), World Scientific Publishing Co. Pte. Ltd., vol. 13(03), pages 1-15, September.

Saunders, A., & Walter, I. (1994). Universal Banking in the United States: What Could We Gain? What Could We Lose? : Oxford University Press.

Shaban, M., Duygun, M., Anwar, M., & Akbar, B. (2014), 'Diversification and banks’ willingness to lend to small businesses: Evidence from Islamic and conventional banks in Indonesia', Journal of Economic Behavior & Organization, 103, S39-S55. doi:10.1016/j.jebo.2014.03.021

Shepherd, W. G. (1986), 'Tobin's q and the Structure-Performance Relationship: Comment', American Economic Review, 76(5), 1205-1210.

Sumera Anis & Abdul Rashid, 2017. "Optimal Bank Capital And Impact Of The Mm Theorem: A Study Of The Pakistani Financial Sector," Annals of Financial Economics (AFE), World Scientific Publishing Co. Pte. Ltd., vol. 12(02), pages 1-21, June.

Tai-Yuen Hon & Massoud Moslehpour & Kai-Yin Woo, 2021. "Review on Behavioral Finance with Empirical Evidence," Advances in Decision Sciences, Asia University, Taiwan, vol. 25(4), pages 15-41, December.

Winton, A. (1999), 'Don't Put All Your Eggs in One Basket? Diversification and Specialization in Lending', SSRN Electronic Journal. doi:10.2139/ssrn.173615



How to Cite

M. Johari, S., Wong, W.-K. ., & Fitri Ayu L.C., A. R. . (2022). Driven Determinants to Indonesia Sharia Commercial Banks’ Performance: The Important Role of Diversification Strategy. Advances in Decision Sciences, 26(2), 64-96.