Standard Life has lowered 600,000 savers' with-profits bonus rates for 2013 as its Heritage fund saw an overall return just shy of 8%.
It said the fund returned 7.9% and plans had seen a real increase in value from last year.
Unitised life plans will see bonus rates drop from 0.75% to 0.5% and unitised pension plans from 1% to 0.5%. The life and pensions firm said with profits bonds would see a 2.5% bonus rate, the same as last year.
A spokeswoman said 600,000 people would be affected and the decision was taken to give the business greater investment flexibility.
Margaret Flaherty, Standard Life's with-profits communications manager, said: "In the last year a typical pension customer has seen a return of 7% on their plan while a typical endowment customer has seen a return of 5% - every customer is contacted individually with updated information on their plan."
Avoids paperwork with two-step process
Investment process will use machines
Mark Sterling accused of operating a collective investment scheme without authorisation
'Increasing engagement will only favour those prepared to put in the effort'