Oklahoma Teachers Retirement System, Oklahoma City, narrowed a search for two additional domestic fixed-income managers to four finalists from six, said Bill Puckett, investment officer. He said the search is to diversify the $5.3 billion fund. The four finalists are Loomis, Sayles; PIMCO; Payden & Rygel; and Western Asset Management. Mr. Puckett said $250 million will be allocated to each new manager. A decision is expected by the end of the month.