In this release, the IRS announced updated interest rates under Section 6621 for the quarter beginning April 1, 2026.
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ADMINISTRATIVE
Rev. Rul. 2026-5, page 542.
Interest rates: underpayments and overpayments. The rates for interest determined under Section 6621 of the code for the calendar quarter beginning April 1, 2026, will be 6 percent for overpayments (5 percent in the case of a corporation), 6 percent for underpayments, and 8 percent for large corporate underpayments. The rate of interest paid on the portion of a corporate overpayment exceeding $10,000 will be 3.5 percent.