WASHINGTON (AP) — Interest rates on short-term Treasury bills were mixed in Monday’s auction with three-month bills unchanged and six-month bills dropping to their lowest level in three weeks.

The Treasury Department auctioned $26 billion in three-month bills at a discount rate of 0.025 percent, unchanged from last week. Another $24 billion in six-month bills was auctioned at a discount rate of 0.055 percent, down from 0.060 percent last week.

The six-month rate was the lowest since those bills stood at 0.050 percent on June 23.

The discount rates reflect that the bills sell for less than face value. For a $10,000 bill, the three-month price was $9,999.37 while a six-month bill sold for $9,997.22. That would equal an annualized rate of 0.025 percent for the three-month bills and 0.056 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, was 0.11 percent last week, unchanged from the previous week.

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