T-Bill Rates Rise to Highest in 4 Years

The Treasury Department auctioned $17 billion in three-month bills at a discount rate of 2.975%, up from 2.965% last week. An additional $15 billion in six-month bills was auctioned at a discount rate of 3.120%, up from 3.060% last week.

The new discount rates understate the actual return to investors -- 3.039% for three-month bills, with a $10,000 bill selling for $9,924.80 and 3.214% for a six-month bill selling for $9,842.27.

Separately, the Federal Reserve said the average yield for one-year Treasury bills, a popular index for making changes in adjustable-rate mortgages, edged up to 3.30% last week from 3.28% the previous week.