The Treasury Department sold $10 billion in four-week bills at a discount rate of 2.450 percent Tuesday, up from 2.250 percent last week.
It was the highest rate since Sept. 5 when the bills sold for 3.430 percent. The government began selling the four-week bills at weekly auctions on July 31.
The new discount rates understate the actual return to investors -- 2.495 percent for four-week bills with a $10,000 bill selling for $9,980.90.
Individual investors can purchase new bills from banks and brokerage houses.