Rates mixed at weekly US Treasury bill auction with 3-months bills down to lowest since 2011

Interest rates on short-term Treasury bills were mixed in Monday's auction, with rates on three-month bills declining to their lowest level since late 2011, while rates on six-month bills rose.

The Treasury Department auctioned $24 billion in three-month bills at a discount rate of 0.010 percent, down from 0.015 percent last week. Another $24 billion in six-month bills was auctioned at a discount rate of 0.100 percent, up from 0.080 percent last week.

The three-month rate was the lowest since three-month bills averaged 0.005 percent on Dec. 19, 2011. The six-month rate was the highest since these bills averaged 0.105 percent on April 13.

The discount rates reflect that the bills sell for less than face value. For a $10,000 bill, the three-month price was $9,999.75, while a six-month bill sold for $9,994.94. That would equal an annualized rate of 0.010 percent for the three-month bills and 0.102 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 up to 0.28 percent last week from 0.27 percent the previous week.