As a broad statement, the IRS charges interest on underpayments and pays interest on overpayments. The interest rates are set quarterly and the rates for the third quarter of 2024 are unchanged from the prior quarter. They are 8% for overpayments (7% for corporations), 8% for underpayments, 10% for large corporate underpayments, and 5.5% for corporate overpayments exceeding $10,000. Interest is charged on estimated tax underpayments that don’t fall within a safe harbor, so keep this in mind when figuring the second installment of estimated taxes for 2024 due on June 17, 2024. #IdeaoftheDay