Rates on US Treasury bills nearly reach a 10-year high

Interest rates on short-term Treasury bills rose in Monday's auction to their highest levels in nearly a decade.

The Treasury Department auctioned $48 billion in three-month bills at a discount rate of 1.89 percent, up from 1.84 percent last week. Another $42 billion in six-month bills was auctioned at a discount rate of 2.035 percent, up from 2 percent last week.

The three-month rate was the highest since those bills averaged 1.9 percent on June 30, 2008. The six-month rate was the highest since those bills averaged 2.06 percent on July 7, 2008.

The discount rates reflect that the bills sell for less than face value. For a $10,000 bill, the three-month price was $9,952.23 while a six-month bill sold for $9,897.12. That would equal an annualized rate of 1.925 percent for the three-month bills and 2.085 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, stood at 2.28 percent on Friday, up slightly from the beginning of last week, May 7, when the yield stood at 2.25 percent.