Rev. Rul. 2023-17, page 798.

Interest rates: underpayments and overpayments. The rates for interest determined under Section 6621 of the code for the calendar quarter beginning October 1, 2023, will be 8 percent for overpayments (7 percent in the case of a corporation), 8 percent for underpayments, and 10 percent for large corporate underpayments. The rate of interest paid on the portion of a corporate overpayment exceeding $10,000 will be 5.5 percent.