The Relationship between Market Power and Income Diversity with Ownership Structure as a Moderator – A Study of Vietnamese Commercial Banks

The Project on Restructuring the Credit Institution System in the first period from 2011 to 2015 and the second period from 2016 to 2020 emphasizes the important role of reducing the relying on traditional activities and increase the share of income from non-credit services. The level of non-interest income, per contra, varies from bank to bank. The paper, therefore, was conducted to examine the relationship between market power and income diversity by using a sample of 26 commercial banks during 2007 to 2017. The market power was proxied by both conventional and adjusted Lerner index; the quotient of non-interest income to total operating income represents the income diversity; and ownership structure, treated as a dummy variable, plays a role as moderator this relationship. Additionally, bank characteristics and country characteristics were considered to be control and dummy variables in the research model. Based on panel data analysis with GMM estimator, the results point out that the bank with greater market power can generate more non-interest income. This relationship, moreover, is impacted by ownership structure, which explains the activities managers and owners do in a bank. For more specific, this paper also highlights the positive impact of state ownership on the association between bank market power and its income diversity. The findings are expected to add the gap in the existing literature, lacking of investigation the impact of market power on bank income diversity in Vietnamese banking sector and give some useful implications for investors, bank managers as well as policy makers to catch up the market fluctuations.