WASHINGTON (AP) – Interest rates on short-term Treasury securities rose in Monday’s auction.

The Treasury Department sold $18 billion in three-month bills at a discount rate of 1.060 percent, up from 0.985 percent last week. An additional $15 billion was sold in six-month bills at a rate of 1.340 percent, up from 1.175 percent.

The three-month rate was the highest since June 2, 2003, when the bills sold for 1.110 percent. The six-month rate was the highest since Nov. 4, 2002, when the rate was 1.395 percent.

The new discount rates understate the actual return to investors – 1.078 percent for three-month bills, with a $10,000 bill selling for $9,973.20, and 1.368 percent for a six-month bill selling for $9,931.90.

In a separate report, the Federal Reserve said Monday that the average yield for one-year constant maturity Treasury bills rose to 1.63 percent last week.

from 1.55 percent the previous week.

AP-ES-05-10-04 1558EDT