UPDATE 1-Investec to hive off asset management unit

(Adds details, CEO comment)

JOHANNESBURG, Sept 14 (Reuters) - Investec plans to hive off and separately list its asset management unit, it said on Friday, in a strategic overhaul that comes ahead of the departure of founder and boss of the Anglo-South African financial services group.

"It is now the right time to demerge and list our asset management business to support it in the next phase of its development," outgoing chief executive Stephen Koseff said in a statement.

Investec's asset management unit has 109 billion pounds ($143 billion) in clients' assets under custody, with offices in several cities such as London, Cape Town, New York and Hong Kong.

The proposed deal, the details of which are yet to be worked out, comes ahead of the departure of Koseff, who will step down next month after four decades at the helm.

Under the deal, the current head of the asset management business, Hendrik du Toit, would be the chief executive of that business, while Fani Titi would become the CEO of investment banking business, or what is left of Investec. (Reporting by Tiisetso Motsoeneng; Editing by Jason Neely and Mark Potter)