Interest rates on short-term T-bills were mixed.

The Treasury Department sold $6.6 billion in new three-month bills at an average discount rate of 5.81%, up from 5.70% last week. Another $6.6 billion was sold in new six-month bills at an average discount rate of 6.10%, down from 6.18% last week. The rates for three-month bills were the highest since May 18 when they averaged 6.03%. The rates on six-month bills were the lowest since they sold for 5.74% on May 11. The new discount rates understate the actual return to investors--6% for three-month bills, with a $10,000 bill selling for $9,853.10, and 6.40% for six-month bills selling for $9,691.60. The discount rate reflects the price discount received when government securities are purchased at less than face value.