Interest rates on short-term Treasury bills fell in Monday's auction with rates on six-month bills falling to the lowest level since late January.

Interest rates on short-term Treasury bills fell in Monday’s auction with rates on six-month bills falling to the lowest level since late January.

The Treasury Department auctioned $35 billion in three-month bills at a discount rate of 0.085 percent, down from 0.095 percent last week. Another $30 billion in six-month bills was auctioned at a discount rate of 0.110 percent, down from 0.115 percent last week.

The three-month rate was the lowest since these bills averaged 0.070 percent on Feb. 4. The six-month rate was the lowest since these bills averaged 0.095 percent on Jan. 22.

The discount rates reflect that the bills sell for less than face value. For a $10,000 bill, the three-month price was $9,997.85 while a six-month bill sold for $9,994.44. That would equal an annualized rate of 0.086 percent for the three-month bills and 0.112 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 0.15 percent last week, the same as the previous week.