WASHINGTON (AP) — Interest rates on short–term Treasury bills rose in Monday's auction to the highest levels since last August.

The Treasury Department auctioned $33 billion in three–month bills at a discount rate of 0.08 percent, up from 0.05 percent last week. Another $31 billion in six–month bills was auctioned at a discount rate of 0.10 percent, up from 0.075 percent last week.

The three–month rate was the highest since three–month bills averaged 0.115 percent on Aug. 1. The six–month rate was the highest since these bills averaged 0.150 percent, also on Aug. 1.

The discount rates reflect that the bills sell for less than face value. For a $10,000 bill, the three–month price was $9,997.98, while a six–month bill sold for $9,994.94. That would equal an annualized rate of 0.081 percent for the three–month bills and 0.102 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, edged up to 0.13 percent last week from 0.12 percent the previous week.