Interest rates on short-term Treasury bills rose in Monday’s auction, and rates on three-month bills climbed to their highest level since late February. The Treasury Department auctioned $30 billion in three-month bills at a discount rate of 0.095 percent, up from 0.08 percent last week. Another $28 billion in six-month bills sold at a discount rate of 0.145 percent, up from 0.13 percent last week.