Corporate Income Tax Deadlines | North Dakota Office of State Tax Commissioner

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2026

January 15

Fourth quarter installment for 2025 estimated income tax is due for calendar year-end taxpayers.

April 15

First quarter installment for 2026 estimated income tax is due for calendar year-end taxpayers.
Form 40 corporation income tax return and tax are due for 2025 calendar year-end taxpayers (Note: This date does not apply to a corporation that is a tax-exempt entity or cooperative. See May 15 and September 15.)

May 15

Form 40 corporation income tax return and tax are due for 2025 calendar year-end tax-exempt organizations that are required to report unrelated business taxable income.

June 15

Second quarter installment for 2026 estimated income tax is due for calendar year-end taxpayers.

September 15

Third quarter installment for 2026 estimated income tax is due for calendar year-end taxpayers.
Form 40 corporation income tax return and tax are due for 2025 calendar year-end cooperatives.

November 16

Important Note: Because November 15 falls on a Sunday, any return, tax payment, estimated payment, or other required action is not due until Monday, November 16.
Form 40 corporation income tax return is due for 2025 calendar year-end taxpayers with a federal extension.

December 15

Form 40 corporation income tax return is due for 2025 calendar year-end tax-exempt organizations with a federal extension that are required to report unrelated business taxable income.