The rate on six-month bills was unchanged. The Treasury Department sold $7.6 billion in new three-month bills at an average discount rate of 7.19%, up from 7.15% last week. Another $7.6 billion was sold in new six-month bills at an average discount rate of 7.26%, the same as last week. The three-month rate was the highest since 7.24% on Nov. 18, while the six-month rate was the highest since 7.3% on Nov. 4. The new discount rates understate the actual return to investors--7.42% for three-month bills and 7.64% for six-month bills. The discount rate reflects the price discount received when government securities are purchased at less than face value.