Interest rates on short-term Treasury securities rose in Monday's auction.
The Treasury Department sold $15 billion in three-month bills at a discount rate of 1.210 percent, up from 1.205 percent last week.
An additional $15 billion was sold in six-month bills at a rate of 1.265 percent, up from 1.245 percent.
The new discount rates understate the actual return to investors -- 1.228 percent for three-month bills with a $10,000 bill selling for $9,969.80, and 1.291 percent for a six-month bill selling for $9,936.40.
In a separate report, the Federal Reserve said Monday that the average yield for one-year constant maturity Treasury bills, the most popular index for making changes in adjustable rate mortgages, rose to 1.51 percent last week from 1.46 percent the previous week.