UK - Trustees have been urged to halt moves towards passive equity funds and reconsider the benefits of active investing, Hewitt Associates said.
The investment consultant said there was a "rising demand" among schemes for passive investment options.
But it warned moving to such passive management could give away a considerable amount of upside - noting excess net returns of three percentage points a year from active investing would compound over ten years to deliver an additional 34.4% growth in assets.
Hewitt Associates manager research team UK head Lennox Hartman said: "Falling asset values and under-performance from many active managers have dealt pension funds a double blow leading trustees to reconsider not just their allocation to equities, but also the merits of active over passive investing."
He added: "However, the opportunities currently available to active managers are arguably greater than usual.
"We firmly believe that it is possible to identify a group of actively managed funds which have the ability perform better, on average, than the benchmark and to achieve material returns."
Hewitt Associates UK head of equity manager research Mark Howdle explained: "The second half of last year was exceptionally difficult for active managers, as share prices were less driven by fundamental factors than usual.
"Market declines were sharp and indiscriminate, but equity markets appear to be inefficient enough to provide skilful managers with opportunities to generate some excess return. While market recovery will ease the troubles of pension funds, it will not solve them in isolation. Even a small active return compounds significantly over time.
"We would argue that now is the time to take care in selecting those active managers most likely to produce superior returns, while mitigating market risk. Those who judge active management on the basis of an unprecedented period, may regret the missed opportunity in years to come."
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