The news comes following the successful shareholder vote to proceed with the demerger of Investec and listing of Ninety One and Investec's announcements on 31 January 2020 regarding Ninety One's expected intention to float.
The global offer will comprise up to 10% of the combined total issued shares, which will be available to both Ninety One staff along with institutional investors.
Ninety One will be listed on both the main market of the London Stock Exchange (LSE) and the main board of the Johannesburg Stock Exchange (JSE).
The firm intends to have a free float of 60-65% of newly issued shares, of which 55% will be held by Investec ordinary shareholders, 15% will be retained by Investec Group, 20% will be held by staff members of Ninety One and 10% will be held by new or existing institutional clients.
There is an expectation that, once listed, the firm would be eligible for inclusion in "several equity indices" including the FTSE UK index series.
Henrik du Toit, joint CEO of Investec and Ninety One founder, said: "After 29 years as part of a diversified financial services group, this is an important event in our development.
"This transaction strengthens our offering to clients as an independent specialist investment manager. Combined with our unique ownership structure, this enhances our efforts to attract and retain the very best talent."
He added: "The dual-listing structure will acknowledge our South African roots, while the London listing positions us for continued international growth."
The timetable for the IPO is as follows:
Publication of Prospectus - 2 March 2020
Latest time for indications of interest - Midday, 13 March
Announcement of the number of shares and the final offer price - 16 March
Admission of shares to the JSE - 7am, 16 March
Admission of shares to LSE - 8am, 16 March
Despatch of share certificates - by 20 March