Bank of Ireland Asset Management has retained its number one position as the best-performing long-term pension fund manager with a 15 per cent annual return over the past 10 years. However, its fund performance over shorter periods has weakened, according to figures from the Irish Pensions Trust and Mercer.

Investments like pensions are best valued on their long-term performance despite the penchant of some providers to emphasise their returns over a year and sometimes even a quarter.

The worst 10-year performers of the 16 pensions 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.