Standard Bank announced on Thursday that Kennedy Bungane, CEO of Corporate and Investment Banking South Africa (CIB SA), had resigned.
Bugane would continue his career in the financial services industry following his decision to join a competitor, it said.
"Mr Bungane has made a significant contribution to Standard Bank over his 20 years of service. This contribution extended to the industry as a whole through the role he played in the design of the Financial Sector Charter as President of the Association of Black Securities and Investment Professionals at the time.
"In the last five years, Mr Bungane has been intimately involved in the evolution of CIB and the Standard Bank of South Africa through his roles as Deputy CEO and CEO of the CIB SA. He has been a strong advocate for the central role that the South African business can play in the broader CIB context," the bank said.
"With immediate effect, Mr Bungane's responsibilities will be reassigned and a further announcement will be made in due course," it added.