Rates rise at weekly US Treasury bill auction

Interest rates on short-term Treasury bills rose in Tuesday's auction to their highest levels since the fall of 2008.

The Treasury Department auctioned $39 billion in three-month bills at a discount rate of 0.960 percent, up from 0.920 percent last week. Another $33 billion in six-month bills was auctioned at a discount rate of 1.060 percent, up from 1.050 percent last week.

The three-month rate was the highest since those bills averaged 1.250 percent on Oct. 20, 2008. The six-month rate was the highest since those bills averaged 1.100 percent on Nov. 3, 2008.

The discount rates reflect that the bills sell for less than face value. For a $10,000 bill, the three-month price was $9,975.73, while a six-month bill sold for $9,946.41. That would equal an annualized rate of 0.976 percent for the three-month bills and 1.081 percent for the six-month bills.

The weekly auction is normally held on Monday but was held on Tuesday this week because of the Memorial Day holiday.

Separately, the Federal Reserve said Tuesday that the average yield for one-year Treasury bills, a popular index for making changes in adjustable rate mortgages, rose to 1.17 percent last Friday, up from 1.14 percent on May 23.