Form 2220, Underpayment of Estimated Tax by Corporations

Form 2220, Underpayment of Estimated Tax by Corporations, is the IRS form that corporations, including S corporations, tax-exempt organizations subject to the unrelated business income tax, and private foundations use to determine whether they owe the estimated tax underpayment penalty and the amount of that penalty for the period that applies.

The form has four parts and a two-part schedule:

• Part I, Required Annual Payment (lines 1 to 5): starts from total tax and arrives at the smaller of the current-year tax or the prior-year tax.
• Part II, Reasons for Filing (lines 6 to 8): boxes for the adjusted seasonal installment method, the annualized income installment method, and a large corporation figuring its first installment on the prior year's tax.
• Part III, Figuring the Underpayment (lines 9 to 18): works through the four installments and shows any underpayment on line 17.
• Part IV, Figuring the Penalty (lines 19 to 38): counts the days of underpayment by period and totals the penalty on line 38.
• Schedule A (pages 3 and 4): the adjusted seasonal and annualized income methods, which can lower or eliminate the required installments.

The penalty is figured separately for each installment due date, so a corporation can owe it for an earlier date even if it paid enough later. The form is OMB No. 1545-0123 and is attached to the corporation's tax return, for example Form 1120, when it has to be filed. Form 8842 is a separate election form that the instructions name for the optional annualization periods.

Corporations (including S corporations), tax-exempt organizations subject to the unrelated business income tax, and private foundations use Form 2220 to determine whether they are subject to the underpayment penalty and how much it is.

Generally, the corporation does not have to file the form, because the IRS figures the penalty and notifies it of any amount due. The corporation may still use the form to figure the penalty itself; in that case it enters the amount from line 38 on the estimated tax penalty line of its return and does not attach the form.

You must complete and attach Form 2220 to the return, even if no penalty is owed, when the Part I, line 3 amount is at or above the minimum printed on the form and any of these applies:

• the adjusted seasonal installment method is used (box on line 6);
• the annualized income installment method is used (box on line 7);
• the corporation is a "large corporation" figuring its first required installment on the prior year's tax (box on line 8). The instructions for line 8 define this as a corporation other than an S corporation whose taxable income reached the stated threshold in any of the 3 preceding tax years.

Do not complete or file the form if line 3 is below that minimum: the corporation does not owe the penalty. For tax year 2025, corporations affected by the corporate alternative minimum tax (CAMT) relief must still file Form 2220 even if they owe no penalty.

Form 2220 has no due date of its own: when it must be filed, it goes with the corporation's tax return and is due when that return is due. The 2025 instructions say that if a box in Part II is checked, the form is attached to the income tax return, and that you also check the box on Form 1120, page 1, line 34 (or the comparable line of the other income tax return).

The installments themselves are due on the 15th day of the 4th, 6th, 9th and 12th months of the tax year (Form 990-PF filers use the 5th month for the first). The period of underpayment generally runs from the installment due date to the earlier of the payment date or the 15th day of the 4th month after the close of the tax year. C corporations with tax years ending June 30 and S corporations use the 3rd month; Form 990-PF and 990-T filers use the 5th. If you elect Option 1 or Option 2 annualization periods, Form 8842 must be filed by the due date of the first required installment.

Form 2220 is submitted as an attachment to the corporation's income tax return; it has no address, portal or appointment process of its own.

• Attached to the return: if you checked any box in Part II, or the instructions otherwise require the form, attach it to the corporation's return (Form 1120, or for example Form 1120-C, 1120-L or 1120-S) and file the return as you normally would. Check the box on Form 1120, page 1, line 34, or the comparable line of another return.
• Not attached: if you use the form only to figure the penalty and no Part II box applies, enter the line 38 amount on the estimated tax penalty line of the return and do not attach the form.
• Extra computations: if you made more than one payment toward a required installment, attach a separate computation for each payment. If a fiscal-year corporation has an underpayment period that runs past the latest date in Part IV, line 35, attach a computation of the penalty for that period and include it in line 38.

For quarterly penalty interest rates, see the IRS website at www.irs.gov or call 800-829-4933. FillingPDF lets you fill out and download the PDF; submission follows the channels that apply to the return it is attached to.