Stephen Koseff, the entrepreneur who co-founded Anglo-South African investment bank and asset manager Investec, will step down as chief executive in October, ending four decades with the group.

Koseff, 66, was instrumental in transforming Investec from a small leasing outfit in Johannesburg into a global investment banker and asset manager with operations in South Africa, Australia and the United Kingdom.

“When we joined Investec almost 40 years ago we aspired to develop a leading financial services group,” Koseff said in a statement.

Two other founding members, Bernard Kantor and Glynn Burger, will also step down as the company’s managing director and financial director, respectively.

Chairman Fani Titi and head of Investec’s asset management business Hendrik du Toit have been picked as joint chief executives.

Shares in Investec fell nearly 4% to 89.40 rand in Johannesburg, tracking broader declines on the bourse and in the sector.