US Treasury bill rates mixed in weekly auction with 3-month bills rising to highest since June

Interest rates on short-term Treasury bills were mixed in Monday's auction with three-month bills rising to the highest level since late June while rates on six-month bills were unchanged.

The Treasury Department auctioned $29 billion in three-month bills at a discount rate of 0.030 percent, up from 0.025 percent last week. Another $25 billion in six-month bills was auctioned at a discount rate of 0.050 percent, the same as last week.

The three-month rate was the highest since these bills averaged 0.040 percent on June 30.

The discount rates reflect that the bills sell for less than face value. For a $10,000 bill, the three-month price was $9,999.24 while a six-month bill sold for $9,997.47. That would equal an annualized rate of 0.030 percent for the three-month bills and 0.051 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 down to 0.11 percent last week from 0.12 percent the previous week.