The Internal Revenue Service on 8 September 2017 announced that interest rates will remain the same for the calendar quarter beginning October 1, 2017. The rates will be four percent for overpayments (three percent in the case of a corporation); one and one-half (1.5) percent for the portion of a corporate overpayment exceeding $10,000; four percent for underpayments; and six percent for large corporate underpayments.
Under the Internal Revenue Code, the rate of interest is determined on a quarterly basis. For taxpayers other than corporations, the overpayment and underpayment rate is the federal short-term rate plus 3 percentage points.
Generally, in the case of a corporation, the underpayment rate is the federal short-term rate plus 3 percentage points and the overpayment rate is the federal short-term rate plus 2 percentage points. The rate for large corporate underpayments is the federal short-term rate plus 5 percentage points. The rate on the portion of a corporate overpayment of tax exceeding $10,000 for a taxable period is the federal short-term rate plus one-half of a percentage point.
The interest rates are computed from the federal short-term rate determined during July 2017 to take effect from August 1, 2017, based on daily compounding.
