Beyond Board Governance: Does the External Governance Ecosystem Enhance Corporate Value in Emerging Markets? Evidence from Listed Nigerian Banking Institutions

Purpose This study investigates whether the external governance ecosystem enhances the corporate value of listed Nigerian banking institutions. Moving beyond the traditional board-centric approach, it examines the influence of regulatory oversight, external audit quality, and environmental governance as complementary external governance mechanisms operating through monitoring, credibility, and legitimacy channels. Methodology/Approach The study draws on agency, institutional, and stakeholder theories and employs a longitudinal panel design covering 11 listed Nigerian banking institutions over the period 2012-2025. Using 154 firm-year observations, Tobin’s Q serves as the measure of corporate value. The Prais-Winsten Panel-Corrected Standard Errors (PCSE) estimator is applied to address heteroskedasticity, serial correlation, and cross-sectional dependence. Firm size, leverage, and profitability are included as control variables. Findings The results reveal that regulatory oversight has a positive but statistically insignificant effect on corporate value, while external audit quality and environmental governance exhibit negative but insignificant effects. Among the control variables, firm size and leverage significantly reduce corporate value, whereas profitability has a positive but insignificant relationship with firm value. The findings suggest that external governance arrangements do not automatically generate market valuation benefits within emerging-market banking institutions. Originality/Value The study contributes to corporate governance literature by introducing an external governance ecosystem perspective that conceptualizes regulatory oversight, external audit quality, and environmental governance as interconnected governance institutions rather than isolated mechanisms. It also extends evidence from the underexplored context of Nigerian banking institutions and emerging markets. Practical Implications The findings highlight the importance of strengthening governance enforcement, disclosure credibility, and sustainability integration. Regulators, managers, and investors should focus on governance effectiveness rather than formal compliance, as external governance mechanisms appear to contribute more to transparency, accountability, and institutional legitimacy than to immediate market valuation gains.