Pennsylvania State Employees Retirement System, Harrisburg, is increasing its domestic fixed-income allocation, planning to use a portion of the assets to pay out benefits, according to Sean Sanderson, spokesman. Neither the amount of the increase nor the funding source has been decided. Currently, 18% of the $24 billion fund is invested in fixed income. Manager searches may result, he said. Some or all of the increase also might be distributed among the funds 14 domestic fixed-income managers. System officials are making the move "to protect our investments so we are not forced to sell equities at a disadvantage (when prices are falling), said Mr. Sanderson.