Quarterly IRS Interest Rates Used in Calculating Interest on Overdue Accounts and Refunds of Customs Duties

This notice advises the public that the quarterly Internal Revenue Service interest rates used to calculate interest on overdue accounts (underpayments) and refunds (overpayments) of customs duties will increase from the previous quarter. For the calendar quarter beginning July 1, 2026, the interest rates for underpayments will be 7 percent for both corporations and non-corporations. The interest rate for overpayments will be 7 percent for non-corporations and 6 percent for corporations. This notice is published for the convenience of the importing public and U.S. Customs and Border Protection personnel.