The New Zealand Superannuation Fund, which was set up to partially fund the cost of a ballooning baby boomer pension bill, has ended a 12-year mandate with AMP Capital to manage part of its local equity portfolio.

The pension fund's manager, the Guardians of New Zealand Superannuation, terminated the active equities mandate effective from Oct. 30, it said in a statement. The portfolio was worth $257.5 million, and the decision to end the relationship, which started in 2003, doesn't affect the Super Fund's 5 percent allocation to New Zealand equities.

AMP Capital still has a mandate to manage some of the fund's investments, including unlisted New Zealand property through its AMP Property Portfolio and New Zealand management buy-outs and expansion capital transactions via the AMP Pencarrow Private Equity Fund II.

The so-called Cullen fund, named for its architect former Finance Minister Michael Cullen, spent $28.4 million on base managers' fees and $28.3 million in performance fees in the year ended June 30, compared to $30.8 million and $26.6 million in the 2013 financial year.

The decision to end the AMP Capital mandate comes after the private fund manager lost its deputy head of equities John Phipps earlier this year and more recently senior NZ shares portfolio manager Douglas Lau resigned.