Study concludes that portfolio managers are cutting costs due in part to low interest rates.
The OAK prefers a uniform interest rate for the public workers and two other retirement plans, which a lobbying group says is wrongheaded.
Publica has cut some stocks to de-risk, and will also sell some of its bonds as part of a new strategy.
Group to be led by finance, economic and education ministers.
Proposed two-part pension system mired in controversy.