In tandem with the dismissals, the pension fund is transitioning its foreign developed markets investment to passive or systemic management.
The fund said it was restructuring its equity portfolio which has resulted in four out of six equity manager employees being made redundant.
Following performance analysis over the spring and autumn of this year, AP1 found that a number of equity strategies did not achieve their return targets.
While the underperforming strategies, such as developed markets, are switching to passive or systematic management, some parts will remain fundamentally active including its Swedish equity investments.
Pension funds have been increasingly incorporating ETFs into their portfolios year-over-year, up to 26%, according to a recent study.
AP1 highlighted the transition will result in its annual costs being reduced by a significant margin.
A spokesperson from AP1 told ETF Stream: "Four of our equity managers are redundant and we have negotiations with unions at the moment so it’s not decided yet how many or who that will leave the fund.
"It is due to some restructuring of the equity portfolio that affects our organisational structure. We will continue with active fundamental strategies but will also change from active to passive and/or systematic in some areas.
"We want to improve our possibilities to increase our return but also better manage risk utilisation and saving cost."
With a total of 68 members of staff, AP1 will continue to have six employees working on active equity management following the redundancies.