- 3% for overpayments; 2% in the case of a corporation
- 3% for underpayments
- 5% for large corporate underpayments
- 1/2% for the portion of a corporate overpayment that exceeds $10,000
The 3% interest rate also applies to estimated tax underpayments for the first calendar quarter in 2012 as well as the first 15 days in April 2012.
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. In the case of a corporation, the underpayment rate generally 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. Further, the federal short-term rate that applies during the third month following the taxable year also applies during the first 15 days of the fourth month following the taxable year.
These interest rates are computed from the federal short-term rate during October 2011 to take effect Nov. 1, 2011, based on daily compounding.