Short-term interest rates, as measured by weekly Treasury auctions of 13-week and 26-week bills, bounced up again yesterday to the highest levels since Oct. 5. T-bill rates have been rising and falling with no apparent trend for the past month.

The average discount rate on 13-week bills sold yesterday rose to 13.613 percent from 13.526 percent a week earlier. The investment rate, or equivalent coupon-issue yield, was 14.29 percent compared with 14.2 percent for the previous bill auction Oct. 9.

For 26-week bills, the discount rate was up to 13.795 percent from 13 1/2 percent. Equivalent coupon-issue yields rose to 15.03 percent from 14.69 percent a week ago.

Discount rates understate actual investment yield because some of the price is refunded at the time of purchase, in effect.

The Treasury sold $4.5 billion each of the 13-week and 26-week bills.

Reflecting investor interest in the bills, the total amount of tenders received for three-month bills was $12.1 billion compared with a more typical level of $7 billion to $9 billion.

The new six-month T-bill rate, plus a quarter point, is 14.045 percent, which becomes the highest rate that banks and thrift institutions may pay starting today on six-month money market certificates issued in denominations of $10,000 or more. The previous ceiling for the certificates was 13 3/4 percent.

In the bond and government securities markets yesterday, prices were mixed in quiet trading. Nervousness over the heavy supply of new tax-exempt issues coming to market this week--including a $96 million Maryland general obligation issue on Wednesday--was instrumental in pressing municipal prices lower and interest rates higher, dealers said.