The wealth management business already has a 78.15 per cent holding in Perennial and will buy the remaining 21.85 per cent equity held by its management.
The purchase price will be $67.9 million plus a potential deferred payment based on Perennial's 2008/09 financial performance. IOOF will also pay key Perennial executives an initial $9.4 million plus a deferred payment.
"We have obviously had a close working relationship with Perennial operating independently and that will remain the case under the new shareholding structure," IOOF chief executive Ron Dewhurst said.
"We believe acquiring the remaining equity in the business provides IOOF with a transparent platform for growth while increasing our exposure to one of our core businesses."
The transaction represents an acquisition multiple of 25 times net profit after tax, with an initial payment based on a Perennial valuat of $320 million.
The transaction is expected to be completed by the end of November, but is subject to shareholder approval at the annual general meeting on November 15.
Perennial last month reported an increase of more than 50 per cent in its funds under management for the year ending June 30.
