Bank of Ireland Asset Management has retained its No 1 position as the bestperforming long-term pension fund manager with a 15 per cent annual return over the past 10 years, but its fund performance over shorter periods has weakened, according to figures from the Irish Pensions Trust and Mercer.

Investments such as pensions, however, are best valued on long-term performance, despite the penchant of some providers to emphasise returns over a year.

Guardian Life and New Ireland (now part of Bank of Ireland) were the next best performers over 10 years, with annual returns of 14.8 per cent and 14.6 per cent. The worst 10-year performers of the 16 pension fund managers surveyed separately by IPT and Mercer were Irish Life with 13.1 per cent and AIB Investment Managers with 12.9 per cent. The average annual return over 10 years is 14 per cent against average inflation of 2.6 per cent.

Over five years, Eagle Star is the clear leader with a 24.1 per cent annual return, followed by Standard Life with 20.9 per cent and Equitable Life with 20.6 per cent. The worst five-year performers were Irish Life and Bank of Ireland Asset Management (BIAM) with 18.9 per cent and 19.6 per cent respectively.

The Irish Pensions Trust (IPT) and Mercer figures show BIAM's performance has slipped substantially over the past five years.

Short-term performance - over the past year - shows a strong performance by Montgomery Oppenheim, which was by far the best performer with a 41.8 per cent return in 1997, well ahead of Norwich Union and Equitable Life in second place with 37.2 per cent. The worst one-year performer was Canada Life with a 27.1 per cent return, well below the 34.2 per cent average.

Montgomery Oppenheim, Norwich Union and Equitable Life were not involved in the pensions market to any significant degree a decade ago and are not included in the 10-year figures from IPT and Mercer.