IR-2013-55, May 23, 2013 WASHINGTON ― The Internal Revenue Service today announced that interest rates will remain the same for the calendar quarter beginning July 1, 2013, as in the prior quarter. The rates will be: three (3) percent for overpayments [two (2) percent in the case of a corporation]; three (3) percent for underpayments; five (5) percent for large corporate underpayments; and one-half (0.5) percent for the portion of a corporate overpayment exceeding $10,000. 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 (0.5) of a percentage point. The interest rates announced today are computed from the federal short-term rate determined during April 2013 to take effect May 1, 2013, based on daily compounding. The interest rates are provided in Revenue Ruling 2013-10 PDF. Follow the IRS on New Media Subscribe to IRS Newswire