• 8 percent for overpayments, 7 percent in the case of a corporation
  
• 8 percent for underpayments
  
• 10 percent for large corporate underpayments
  
• 5.5 percent for the portion of a corporate overpayment exceeding $10,000.

The rate of interest is determined on a quarterly basis under the Internal Revenue Code (IRC). 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 taxable period is the federal short-term rate plus 0.5 of a percentage point. The interest rates just announced are computed from the federal short-term rate, based on daily compounding determined during in October 2006.