The Treasury Department sold $6.4 billion in new three-month bills at an average discount rate of 5.74%, down from 5.80% last week. Another $6.4 billion was sold in new six-month bills at an average discount rate of 6.24%, unchanged from last week. The three-month rate was the lowest since these securities sold for 5.12% on Oct. 26. Six-month bills had sold for 5.98% on Oct. 26. The new discount rates understate the actual return to investors--5.92% for three-month bills selling for $9,854.90 and 6.55% for six-month bills selling for $9,684.50. The discount rate reflects the price discount received when government securities are purchased at less than face value.