Oklahoma Firefighters Pension and Retirement System, Oklahoma City, is adding global core fixed income to its asset mix, said Jason Pulos, director at Asset Consulting Group, which is assisting the fund. The allocation is being made for diversification, he added. The $1.86 billion fund hopes to hire a manager to run $75 million to $100 million. Funding will come from reducing the domestic core bond portfolio. Bob Jones, director, could not be reached for comment by press time.