Interest rates on short-term Treasury bills rose.

The Treasury Department sold $7.5 billion in new three-month bills at an average discount rate of 5.30%, up from 5.13% last week. Another $7.5 billion was sold in new six-month bills at an average discount rate of 5.39%, up from 5.22% last week. The rates were the highest since three-month bills sold for 5.32% on Aug. 25 and six-month bills averaged 5.65% on Aug. 18. The new discount rates understate the actual return to investors--5.45% for three-month bills and 5.62% for six-month bills. The discount rate reflects the price discount received when government securities are purchased at less than face value.