Regulatory Architecture, Governance Enforcement, and Market Integrity in the Nigerian Capital Market: A Longitudinal Institutional Analysis

This dissertation conducts a longitudinal institutional analysis of the regulatory architecture, governance enforcement mechanisms, and market integrity outcomes in the Nigerian capital market over a twenty-year period. Market integrity, encompassing price discovery efficiency, insider trading prevention, and investor protection quality, is fundamentally dependent on the design and effectiveness of regulatory and governance enforcement systems. Nigeria's capital market has undergone significant regulatory transformation, including the restructuring of the Securities and Exchange Commission, the demutualisation of the Nigerian Exchange Group, and the introduction of multiple market conduct and disclosure regulations. Despite these reforms, governance enforcement and market integrity concerns persist. Drawing on regulatory theory, institutional economics, and capital market governance literature, this study combines longitudinal document analysis of SEC enforcement records, legislative and regulatory reforms, and market integrity data with comparative benchmarking against selected African and emerging market capital markets. A theory of regulatory governance effectiveness is developed and tested through case analysis of three distinct regulatory reform episodes. The study makes original contributions by constructing a twenty-year longitudinal governance enforcement dataset for the Nigerian capital market, developing a regulatory architecture quality index, and identifying the institutional conditions under which enforcement improvements translate into market integrity gains. Findings carry significant implications for SEC reform, investor protection policy, and capital market development strategy. Keywords: regulatory architecture, governance enforcement, market integrity, capital market, institutional analysis.