Pennsylvania’s largest public pension fund paid $1 billion in expenses to outside managers in fiscal 2017 and should consolidate its investment office with the state employees’ fund, according to a study. The recommendations come from a state commission report released Thursday that looked at ways to reduce costs at the state’s largest fund, Pennsylvania Public School Employees’ Retirement System, known as PSERS, and the State Employees’ Retirement System, or SERS. Institutional investors including college endowments and public pensions are seeking to reduce costs by examining fees paid to managers.