BNP Paribas Investment Partners is set to become the 15th largest fund manager in Australia after its expected integration with Fortis Investment Management Australia (Fortis) goes ahead in April.

The combined entity will have $23.2 billion in assets under management (AUM), up from $18.2 billion as at 31 December 2009.

As reported previously, the current chief executive of BNP Paribas Investment Partners Robert Harrison will head up the combined entity in Australia and New Zealand.

Fortis chief executive Ian Manton-Hall will stay on for a transitional period before leaving. It is understood that directors of institutional sales, Kerrie Howard and Martin Smith, have already departed.

As a result of the integration, there are also plans to expand the product offering in Australia and New Zealand to include the distribution of Fortis Investment's funds management expertise in Australian equities and global real estate.

"The merger puts us in a strong position to increase our market share and better serve our clients in Australia and New Zealand, with both the diversification of our product offering and the increase in our client management resources," Harrison said.

Fortis Investment Partners, the Australian equites fund manager currently 40 per cent-owned by Fortis Investment Management Australia, will become one of the 26 specialist partners within the global BNP Paribas Investment Partners network.

BNP Paribas Investment Partners will retain a 40 per cent shareholding in the Australian equities fund manager, which will be rebranded during 2010.

Globally, the merger will mean BNP Paribas Investment Partners will have over $800 billion in AUM and will be the 11th largest asset manager worldwide.