The new rates for the calendar quarter beginning Jan. 1, 2009 will be: 

• Five percent for overpayments (four percent in the case of a corporation)
• Five percent for underpayments
• Seven percent for large corporate underpayments
• Two and one-half 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 of a percentage point.

Revenue Ruling 2008-54, announcing the new rates of interest will appear in Internal Revenue Bulletin No. 2008-52, dated Dec. 29, 2008.