Rates on short-term bills fall at weekly US Treasury auction

Interest rates on short-term Treasury bills fell in Tuesday's auction, with rates on six-month bills dropping to their lowest level in four weeks.

The Treasury Department auctioned $34 billion in three-month bills at a discount rate of 0.530 percent, down from 0.555 percent last week. Another $28 billion in six-month bills was auctioned at a discount rate of 0.630 percent, down from 0.660 percent last week.

The three-month rate was the lowest since three-month bills averaged 0.515 percent two weeks ago on Dec. 19. The six-month rate was the lowest since those bills averaged 0.515 percent four weeks ago on Dec. 5.

The discount rates reflect that the bills sell for less than face value. For a $10,000 bill, the three-month price was $9,986.60, while a six-month bill sold for $9,968.15. That would equal an annualized rate of 0.538 percent for the three-month bills and 0.641 percent for the six-month bills.

Separately, the Federal Reserve said Tuesday that the average yield for one-year Treasury bills, a popular index for making changes in adjustable rate mortgages, stood at 0.85 percent last Friday, down from 0.89 percent on Dec. 27.