Short-term rates rise at weekly US Treasury auction

Interest rates on short-term Treasury bills rose in Monday's auction to their highest levels since August 2008.

The Treasury Department auctioned $51 billion in three-month bills at a discount rate of 1.780 percent, up from 1.670 percent last week. Another $45 billion in six-month bills was auctioned at a discount rate of 1.950 percent, up from 1.850 percent last week.

The three-month rate was the highest since those bills averaged 1.850 percent on Aug. 18, 2008. The six-month rate was the highest since those bills averaged 1.980 percent also on Aug. 18, 2008.

The discount rates reflect that the bills sell for less than face value. For a $10,000 bill, the three-month price was $9,955.00 while a six-month bill sold for $9,901.42. That would equal an annualized rate of 1.813 percent for the three-month bills and 1.997 percent for the six-month bills.

Separately, the Federal Reserve said Monday that the average yield for one-year Treasury bills, a popular index for making changes in adjustable rate mortgages, edged up to 2.08 percent Friday, up from 2.05 percent at the beginning of last week on March 12.