Short-term T-bill interest rates rose slightly.

Rates on the Treasury securities rose slightly to levels in effect at the beginning of the month. The Treasury sold $7.8 billion in three-month bills at an average discount rate of 5.64%, up from 5.60% last week. Another $7.8 billion was sold in six-month bills at an average discount rate of 5.65%, up from 5.60% last week. The rates, while still substantially below levels of a year ago, were the highest since Aug. 4, when three-month bills sold for 5.70% and six-month bills averaged 5.73%.