A partnership’s federal income tax return, Form 1065, is due by the 15th day of the third month after the partnership’s tax year closes.1Office of the Law Revision Counsel. 26 USC 6072 – Time for Filing Income Tax Returns2Internal Revenue Service. Publication 509 (2026), Tax Calendars3Internal Revenue Service. Instructions for Form 1065 (2025) The partnership doesn’t pay income tax on this return; it reports the numbers and passes each partner’s share through on a Schedule K-1.4Internal Revenue Service. About Form 1065, U.S. Return of Partnership Income
Fiscal-Year Partnerships
The three-month rule applies whether or not the partnership uses a calendar year. A partnership with a June 30 fiscal year end files by September 15. One that closes its books October 31 files by January 15. This is a month tighter than the individual fiscal-year rule, which allows four months, so if you’re used to individual deadlines, don’t borrow the timing.
When the calculated date lands on a Saturday, Sunday, or legal holiday, the return is due the next business day.2Internal Revenue Service. Publication 509 (2026), Tax Calendars
Getting a Six-Month Extension
A partnership that needs more time files Form 7004 by the original due date and gets an automatic six-month extension.5Internal Revenue Service. About Form 7004, Application for Automatic Extension of Time To File Certain Business Income Tax, Information, and Other Returns For a 2025 calendar-year partnership, filing Form 7004 by March 16, 2026 moves the deadline to September 15, 2026.
No reason is required. As long as Form 7004 is complete and timely, the extension is granted. One caveat matters: the extension covers filing, not paying. If the partnership owes any tax, such as withholding on foreign partners, that money is still due by the original deadline, and a late payment triggers a separate failure-to-pay penalty.6Internal Revenue Service. Form 7004 (Rev. December 2025) – Application for Automatic Extension of Time To File Certain Business Income Tax, Information, and Other Returns
Schedule K-1 Delivery
The partnership must furnish a Schedule K-1 to each partner by the same date Form 1065 is due, which for the 2025 tax year means March 16, 2026.4Internal Revenue Service. About Form 1065, U.S. Return of Partnership Income Extending the partnership return extends the K-1 delivery date, too. That creates a downstream squeeze for partners: individual returns are due April 15, and a partner still waiting on a K-1 in September almost always has to file their own Form 4868 extension to push their personal deadline to October 15.7Internal Revenue Service. Partners Instructions for Schedule K-1 (Form 1065)
Penalty for Missing the Deadline
A partnership that files Form 1065 late, or files an incomplete return, is penalized under IRC § 6698. For returns due in 2026, the penalty is $245 per partner for each month or partial month the return is late, capped at 12 months.8Office of the Law Revision Counsel. 26 USC 6698 – Failure to File Partnership Return
Because it’s multiplied by both partners and months, the number climbs quickly. A ten-partner firm filing four months late owes $9,800. A fifty-partner firm that hits the twelve-month cap owes $147,000. Since the partnership itself doesn’t pay income tax, this penalty is the main financial risk of a late return.
The same penalty applies to a return that arrives on time but leaves out required information about partnership operations.8Office of the Law Revision Counsel. 26 USC 6698 – Failure to File Partnership Return
How to Get the Penalty Waived
Three paths lead to abatement. Which one fits depends on the partnership’s size and history.
Small Partnership Relief (Rev. Proc. 84-35)
Partnerships of ten or fewer partners get streamlined relief. The IRS presumes reasonable cause and waives the penalty when all four of these conditions hold:9Internal Revenue Service. Understanding Your CP162B Notice
- No more than 10 partners during the tax year, with a married couple filing jointly counted as one.
- Every partner is a natural person (not a nonresident alien) or the estate of one.
- Each partner’s share of every partnership item matches their share of every other item.
- The partnership did not elect into the centralized partnership audit regime under IRC §§ 6221–6234.
Every partner also has to have filed their own returns on time and reported their share of partnership income correctly. When the criteria are met, a letter to the IRS citing Rev. Proc. 84-35 and confirming each condition usually resolves the notice.
First-Time Penalty Abatement
Partnerships with a clean compliance history can request first-time abatement, and the § 6698 penalty is on the list of penalties eligible for it.10Internal Revenue Service. 20.1.1 Introduction and Penalty Relief The partnership must have filed the same type of return in each of the three preceding tax years with no unresolved penalties on those returns. For larger partnerships that fall outside Rev. Proc. 84-35, this is usually the quickest option.
Reasonable Cause
Any partnership can seek abatement by showing reasonable cause: that it exercised ordinary business care and prudence but still couldn’t file on time.11Internal Revenue Service. 12Internal Revenue Service. Reporting and Paying Tax on Partnership Withholding Filing Form 7004 to extend Form 8804 does not extend the time to pay the withholding tax, so the money is still due at the original deadline. A partnership made up entirely of nonresident alien partners has until the 15th day of the sixth month to file Form 8804, though payment is still due on the earlier date.