Treasury Bill Rates Rise to Highest in 3 1/2 Years

The Treasury Department auctioned $20 billion in three-month bills at a discount rate of 2.735%, up from 2.71% last week.

An additional $18 billion in six-month bills was auctioned at a discount rate of 3%, up from 2.935% last week.

The three-month rate was the highest since three-month bills averaged 3.18% on Sept. 10, 2001. The six-month rate was the highest since 3.12% on Sept. 10, 2001.

The new discount rates understate the actual return to investors -- 2.792% for three-month bills, with a $10,000 bill selling for $9,930.87, and 3.089% for a six-month bill selling for $9,848.33.

In a separate report, the Federal Reserve said the average yield for one-year Treasury bills, a popular index for making changes in adjustable-rate mortgages, rose to 3.24% last week from 3.2% the previous week.