* Koseff retires after 40 years with company
* Investec MD, CFO also step down
* Fani Titi, Hendrik du Toit picked as joint CEOs (Adds analysts comment, details)
JOHANNESBURG, Feb 6 (Reuters) - Stephen Koseff, the entrepreneur who co-founded Anglo-South African investment bank and asset manager Investec four decades ago, will step down as chief executive in October as part of a changing of the guard.
Koseff, 66, was instrumental in transforming Investec from a small leasing outfit in Johannesburg into a global investment banker and asset manager with more $200 billion of clients' money under custody and a substantial presence in South Africa, Australia and Britain.
"When we joined Investec almost 40 years ago we aspired to develop a leading financial services group," Koseff, who has been chief executive since 1996, said in a statement.
Two other founding members of the business -- Bernard Kantor and Glynn Burger -- will also retire as the company's managing director and financial director, respectively.
Chairman Fani Titi and Hendrik du Toit -- head of Investec's asset management business -- have been picked as joint chief executives. The two will formally take charge in October.
Investec has largely prospered under Koseff, Kantor and Burger.
Its assets have surged more than 10-fold to over 50 billion pounds ($70 billion) during their tenure and its stock soared more than five-fold thanks to a string of deals.
The company escaped largely unscathed from the global banking crisis a decade ago thanks to tough South African regulation which stopped local lenders buying toxic U.S. mortgage-related assets and a more cautious approach to borrowing.
Titi and du Toit are being promoted to the helm of a company pressing hard to stay focused as a niche player targeting relatively wealthy individuals with banking and wealth management products.
Investec recently launched a life insurance product, initially targeting its high net-worth clients.
Du Toit is expected to be in charge of Investec overseas divisions and while Titi would oversee the company's business in South Africa, where he is based, Koseff told a conference call.
Koseff, whose hobbies include watching English soccer and supporting Tottenham Hotspur -- which once counted Investec as its shirt sponsor -- did not expect a 'dramatic shift" in the company's strategic direction.
Others shared that view.
"Stephen is handing over the reins to two safe pair of hands," said Graeme Körner, a fund manager at Körner Perspective.
"Fani and Hendrik have been with the company for a long time and it's a probably wise move to have joint CEOs because banking is a different animal to asset management," he added.
Other managements changes included the promotion of the company's head of finance at asset management, Kim McFarland, to group CFO while Perry Crosthwaite, a non-executive director, replaces Titi as chairman.
Shares in Investec fell nearly 4 percent to 89.40 rand in Johannesburg, tracking broader declines on the bourse and in the sector, before recovering later in the day. ($1 = 12.0900 rand) ($1 = 0.7162 pounds) (Reporting by Tiisetso Motsoeneng; editing by Jason Neely/Keith Weir)