Rates rise at weekly US Treasury auction

WASHINGTON (AP) - Interest rates on short-term Treasury bills rose in Monday's auction, with six-month rates rising to their highest level since late December.

The Treasury Department auctioned $37 billion in three-month bills at a discount rate of 0.335 percent, up from 0.315 percent last week. Another $30 billion in six-month bills was auctioned at a discount rate of 0.510 percent, up from 0.475 percent last week.

The three-month rate was the highest since those bills averaged 0.350 percent on Feb. 1. The six-month rate was the highest since those bills averaged 0.550 percent on Dec. 28.

The discount rates reflect that the bills sell for less than face value. For a $10,000 bill, the three-month price was $9,991.53, while a six-month bill sold for $9,974.22. That would equal an annualized rate of 0.340 percent for the three-month bills and 0.518 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, rose to 0.68 percent last week from 0.66 percent the previous week.