The Treasury Department auctioned $29 billion in three-month bills at a discount rate of 0.050 percent, unchanged from last week. Another $24 billion in six-month bills was auctioned at a discount rate of 0.080 percent, down from 0.085 percent last week.
The six-month rate was the lowest since these bills averaged 0.075 percent on Jan. 30, 2012.
The discount rates reflect that the bills sell for less than face value. For a $10,000 bill, the three-month price was $9,998.74 while a six-month bill sold for $9,995.96. That would equal an annualized rate of 0.051 percent for the three-month bills and 0.081 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, was unchanged at 0.12 percent last week, the same as the previous week.