Form CT-400 is the New York State form corporations use to make their second, third, and fourth quarterly estimated tax installments toward franchise, excise, or gross receipts tax. It is filed by corporations whose current-year tax is reasonably expected to exceed $1,000, or $5,000 for Article 9-A C corporations in tax years beginning on or after January 1, 2026.1New York State Department of Taxation and Finance. Instructions for Form CT-400 The “CT” stands for corporation tax, not Connecticut.
Who Has to File
Whether you owe estimated payments depends on which article of New York Tax Law governs your corporation and how much tax you expect for the year.2New York State Department of Taxation and Finance. Estimated Tax Requirements for Corporations
- Article 9-A C corporations must file if franchise tax is reasonably expected to exceed $5,000 for the current tax year. Before 2026, the threshold was $1,000.3New York State Senate. New York Tax Law 213-B – Payments on Account of Estimated Tax
- Article 9 and Article 33 corporations must file if franchise, excise, or gross receipts tax is expected to exceed $1,000.1New York State Department of Taxation and Finance. Instructions for Form CT-400
- New York S corporations under Article 9-A are not required to make estimated tax payments.2New York State Department of Taxation and Finance. Estimated Tax Requirements for Corporations
The rules apply equally to corporations formed in New York and foreign corporations doing business there.
Pay the Mandatory First Installment on Form CT-300 First
Before you file your first CT-400 of the year, most corporations owe a mandatory first installment (MFI) on a separate form, Form CT-300. This trips up filers because the MFI is calculated from the tax liability of two years prior, not the current year’s estimate. It is due on the 15th day of the third month of the tax year, which for calendar-year filers is March 15.4New York State Department of Taxation and Finance. Instructions for Form CT-300
The MFI percentage depends on how large that second-preceding-year tax was:
- Article 9-A C corporations owe 25% of the second preceding year’s franchise tax if that tax exceeded $5,000 but was $100,000 or less, and 40% if it exceeded $100,000.4New York State Department of Taxation and Finance. Instructions for Form CT-300
- Article 9 and Article 33 filers (except life insurance companies) owe 25% if the second preceding year’s tax exceeded $1,000 but was $100,000 or less, and 40% above $100,000.4New York State Department of Taxation and Finance. Instructions for Form CT-300
- Life insurance companies always owe 40%, as long as the second preceding year’s tax exceeded $1,000.4New York State Department of Taxation and Finance. Instructions for Form CT-300
New York S corporations do not file Form CT-300.
Calculating Each CT-400 Installment
Once the MFI is paid, subtract it from your total estimated tax for the year and divide the remainder by three. Each of those three equal amounts is reported on a separate Form CT-400.1New York State Department of Taxation and Finance. Instructions for Form CT-400
For a calendar-year corporation, the schedule is:
- MFI on Form CT-300: March 15
- Second installment on Form CT-400: June 15
- Third installment on Form CT-400: September 15
- Fourth installment on Form CT-400: December 15
Fiscal-year filers use the same pattern shifted to match their year-end: the MFI falls on the 15th of the third month, and the three CT-400 installments on the 15th of the sixth, ninth, and twelfth months. When a due date lands on a weekend or legal holiday, the payment is due the next business day.1New York State Department of Taxation and Finance. Instructions for Form CT-400
If your estimate turns out to be too high or too low partway through the year, you can amend the declaration and the remaining installments are adjusted proportionally.3New York State Senate. New York Tax Law 213-B – Payments on Account of Estimated Tax
How to File and Pay
Most corporations must e-file Form CT-400. The electronic filing mandate applies if you use a computer to prepare or calculate your tax forms and have broadband internet access, whether or not you work with a paid preparer. Filing on paper when you meet those conditions can result in penalties.5New York State Department of Taxation and Finance. Form CT-400, Estimated Tax for Corporations
You have two e-file routes. The first is Web File through your Business Online Services account on the Department of Taxation and Finance website, which is free. The second is approved commercial tax software that transmits the form on your behalf.5New York State Department of Taxation and Finance. Form CT-400, Estimated Tax for Corporations Payments go through either ACH debit, where the state pulls funds from your bank account, or ACH credit, where you push funds through your bank.6New York State Department of Taxation and Finance. Electronic Filing Mandate for Business Taxpayers
If you qualify for a paper-filing exception, mail Form CT-400 with a check to: NYS Estimated Corporation Tax, PO Box 15200, Albany, NY 12212-5200.1New York State Department of Taxation and Finance. Instructions for Form CT-400 You will need your Federal Employer Identification Number, your legal business name and address as they appear on file with New York State, the tax year, and the installment number. Confirm the FEIN and tax period before submitting; errors route payments to the wrong account and can trigger false underpayment notices.
Avoiding Underpayment Penalties
Missing or underpaying an installment triggers an addition to tax under Tax Law Section 1085. The penalty is calculated at the underpayment rate set by the Tax Commissioner, or at 7.5% per year if no rate has been set, applied to the shortfall for the period it remains unpaid. It stops accruing on the 15th day of the fourth month after the close of your tax year.7New York State Senate. New York Tax Law 1085 – Underpayment of Estimated Tax
The safe harbor is set at 91% of the tax shown on the current year’s return for installments not based on prior-year tax. A partial relief provision reduces the penalty to 75% of what it would otherwise be if substituting 80% for 91% would eliminate the underpayment.7New York State Senate. New York Tax Law 1085 – Underpayment of Estimated Tax Paying at least 91% of your actual liability across the four installments avoids penalties; staying above 80% at least softens them.
If your income swings sharply through the year, two alternative calculation methods can shrink the required installments: the annualized income installment method and the adjusted seasonal installment method. Both recompute each quarter’s required payment based on income actually earned during the period, so a business that earns most of its revenue late in the year owes less early on. To use either one, complete Form CT-222 and attach it to your annual return. The form automatically picks the smallest required installment from among the annualized method, the seasonal method where applicable, and the standard calculation.8New York State Department of Taxation and Finance. Instructions for Form CT-222 – Underpayment of Estimated Tax by a Corporation
What Changes in 2026
For tax years beginning on or after January 1, 2026, the Article 9-A C corporation threshold rises from $1,000 to $5,000. A C corporation whose second preceding year’s franchise tax was between $1,001 and $5,000 no longer owes a mandatory first installment, though it may still need to file Form CT-400 if its current-year tax is reasonably expected to exceed $5,000.3New York State Senate. New York Tax Law 213-B – Payments on Account of Estimated Tax Article 9 and Article 33 corporations keep the $1,000 threshold.1New York State Department of Taxation and Finance. Instructions for Form CT-400 The $5,000 figure applies to the second preceding year’s tax for MFI purposes and the current-year expected tax for CT-400 filing purposes, so verify both numbers during the transition year before skipping any installment.