Short-term interest rates mixed at weekly Treasury auction

Interest rates on short-term Treasury bills were mixed in Monday's auction with rates on three-month bills unchanged while rates on six-month bills rose to their highest level in more than nine years.

The Treasury Department auctioned $48 billion in three-month bills at a discount rate of 1.430 percent, unchanged from last week. Another $42 billion in six-month bills was auctioned at a discount rate of 1.615 percent, up from 1.600 percent last week.

The six-month rate was the highest since these bills averaged 1.800 percent on Oct. 20, 2008.

The discount rates reflect that the bills sell for less than face value. For a $10,000 bill, the three-month price was $9,963.85 while a six-month bill sold for $9,918.35.

That would equal an annualized rate of 1.455 percent for the three-month bills and 1.651 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 1.79 percent last Thursday, up slightly from 1.78 percent on Jan. 12.