The $3.1 billion Oklahoma Public Employees' Retirement System, Oklahoma City, issued RFPs for active fixed-income managers to invest a total of about $922 million. RFPs are due July 31. The search comes as contracts for three incumbent fixed-income managers - Hoisington, Morgan Grenfell and Alliance - expire. Steve Edmonds, executive director, said a short list of managers to be interviewed is expected by September, with placements expected in October. The incumbents are expected to bid.