Partnerships with foreign partners file two returns on the same March deadline: Form 1065 for the partnership’s income, and Form 8804 for the section 1446 withholding tax on foreign partners’ effectively connected income. The most expensive mistake in this corner of the calendar is extending one and assuming the other rode along.
It didn’t. Form 7004’s own instruction is to file a separate application for each return. Here is how the 8804 extension works.
Due date and the foreign-books variant
The instructions for Forms 8804, 8805, and 8813 set the deadline: file "on or before the 15th day of the 3rd month following the close of the partnership’s tax year" — March 15 for calendar-year partnerships, alongside the 1065. Partnerships keeping their records and books of account outside the United States and Puerto Rico get until the 15th day of the 6th month.
The extension: code 31, filed separately
Form 7004 with code 31 on line 1 extends Form 8804 by the standard 6 months. The critical mechanic: Form 7004 extends exactly one return per application. A partnership extending both its income return and its withholding return files two Forms 7004 — code 09 for the 1065, code 31 for the 8804.
A paper-filing quirk worth knowing: the 7004 for Form 8804 has its own mailing address (P.O. Box 409101, Ogden, UT 84409). E-filing sidesteps the sorting entirely.
The section 1446 tax itself was never waiting for the return: it is paid during the year in installments on Form 8813, with any balance due at the unextended 8804 deadline. The extension moves paperwork, not payment.
What Form 8804 covers, briefly
Section 1446 requires a partnership with income effectively connected to a U.S. trade or business to withhold tax on each foreign partner’s allocable share — whether or not cash is actually distributed. Form 8804 is the annual reconciliation; each foreign partner receives a Form 8805 showing their share of the withholding, which they credit on their own U.S. return. Extending Form 8804 also extends the time to furnish the associated 8805s with it.
Frequently asked questions
Does extending Form 1065 also extend Form 8804?⌄
When is Form 8804 due?⌄
Does the extension delay the withholding tax payment?⌄
How long is the Form 8804 extension?⌄
Related guides
More in Business Tax Extensions (Form 7004)
Official sources
Tax rules, rates and deadlines change — verify current requirements against the IRS sources above before acting. This guide is general information, not tax or legal advice.