Rev. Rul. 2023-4, page 480.

Interest rates: underpayments and overpayments. The rates for interest determined under Section 6621 of the code for the calendar quarter beginning April 1, 2023, will be 7 percent for overpayments (6 percent in the case of a corporation), 7 percent for underpayments, and 9 percent

Finding Lists begin on page ii.

for large corporate underpayments. The rate of interest paid on the portion of a corporate overpayment exceeding $10,000 will be 4.5 percent.