Interest rates remain the same for the fourth quarter of 2025

Key points / rates (annual, compounded daily)Individuals: 7% for overpayments and 7% for underpayments.Corporations: 6% for overpayments; 7% for underpayments.Portion of a corporate overpayment exceeding $10,000: 4.5%.Large corporate underpayments: 9%.Legal / calculation contextInterest rates are set quarterly under the Internal Revenue Code and are expressed as the federal short-term rate plus a statutory number of percentage points.For most taxpayers (non‑corporate), overpayment/underpayment = federal short-term rate + 3 percentage points.For corporations, underpayment = federal short-term rate + 3 percentage points; overpayment = federal short-term rate + 2 points; large corporate underpayments = federal short-term rate + 5 points; overpayment portion over $10,000 = +0.5 points.These rates are computed from the federal short-term rate determined in July 2025.Formal announcement of the rates appears in Revenue Ruling 2025-18 and will be published in Internal Revenue Bulletin 2025-37 (dated Sept. 8, 2025).