KEY POINTS:
The $13.6 billion New Zealand Superannuation fund is expected to review its use of investment manager Brook Asset Management when its co-founders depart.
The Macquarie-owned asset manager announced last week fund managers Simon Botherway and Paul Glass would leave the company at the end of the year.
Since then ratings company Morningstar has downgraded the firm's two key funds, dropping its recommendation on the Tasman fund from highly recommended to investment grade and placing the Brook Alpha strategy on hold.
Morningstar senior research analyst Chris Douglas said he assumed the Super fund, dubbed the "Cullen fund", would also be assessing the impact of the loss of the two managers.
"Paul and Simon are both highly experienced. Their departure is going to have an impact on Brook," he said.
Figures from 2005 show Brook manages about $260 million for the fund and has the highest allocation of the New Zealand managers it uses.
Yesterday a spokeswoman for the New Zealand Superannuation fund said it did not comment on its relationship with individual fund managers.
Brook Asset's managing director Mark Brighouse also would not comment on any individual clients.
The super fund dropped Fisher Funds as an investment manager in April due to the size of its investment and the divergent objectives of the two businesses. Fisher managed around $100 million for the fund, which is now being managed internally.
The fund was set up by Labour five years ago to put money aside to help to meet the cost of future superannuation payments. National wants to increase investment in New Zealand by the fund to 40 per cent.
