Abstract Guaranty Trust Bank (GTB) PLC, a wholly Nigerian business enterprise, founded in 1990, blazed the trail in the banking sector of Nigeria in many respects. By 1995, it had become the fourth most profitable bank in Nigeria and the first indigenous bank to attain a profit-before-tax of one bn naira, and by 2002 had expanded into several West African countries. The significance of the bank is attested by several scholarly studies of its founding, growth, performance and impact. This paper examines a neglected aspect of the history of the bank: its successes and failure in complying with standards of corporate governance and business ethics in a notoriously opaque industry. Specifically, it focuses on the GTB’s relations with statutory regulatory bodies – the Central Bank of Nigeria (CBN) and the National Deposit Insurance Corporation (NDIC) – as well as its shareholders, who kept the bank on its toes on matters of its business operations. Relying on previously unexploited sources, including minutes of the bank’s board of directors, annual reports and oral evidence provided by members of the board, management and staff, and former top employees of the bank, as well as snippets from the reports of the regulatory bodies (which are not to be cited), this paper highlights issues raised by stakeholders about how the bank managed its affairs, and how it dealt with the queries and questions raised by the external regulators and internal stakeholders in the first 15 years of its existence.