The 2026 filing deadlines below are for your 2025 tax year — the return year that comes due this year. As of this update, the two original deadlines have already passed, so what matters now is whether you filed for an extension, and if not, what to do next. Here’s exactly where things stand.
Where things stand right now
- March 16, 2026 — the original deadline for multi-member LLCs taxed as partnerships, filing Form 1065 and issuing K-1s. This date has passed.
- April 15, 2026 — the original deadline for C-Corporations filing Form 1120, and foreign-owned single-member LLCs filing their pro-forma Form 1120 with Form 5472 attached. This date has passed too.
Not sure which one applies to you? As a rule of thumb: one owner, no elections made → the April 15 category. Two or more owners, taxed as a partnership → the March 16 category. We confirm your entity’s filing category as part of onboarding, so you’re never guessing.
Still ahead: the extended deadlines
If Form 7004 was filed by the original date, the return itself isn’t due yet:
- September 15, 2026 — extended deadline for multi-member LLCs filing Form 1065.
- October 15, 2026 — extended deadline for C-Corporations (Form 1120) and foreign-owned single-member LLCs (pro-forma Form 1120 with Form 5472 attached).
Missed the original deadline with no extension on file?
This is fixable, and it’s more common than you’d think — the path forward just depends on your specific situation (how late, what’s owed, whether this is the entity’s first return). Reach out to us and we’ll help you work out the right next step for your case. A filing after the original deadline with no Form 7004 on file is priced as a late filing.
A filing extension is not a payment extension
Form 7004 extends the time to file your return — it does not extend the time to pay any tax owed. If you had a balance due, interest keeps accruing on it from the original deadline (March 16 or April 15), even with an approved extension. That’s true whether you or your tax preparer filed the extension.
Sources: IRS, About Form 7004 and IRS, Instructions for Form 5472 — checked September 2026.
State-side dates worth knowing
Federal filings aren’t the only date on the calendar. If you formed in Wyoming or Delaware, keep these in mind too:
- Wyoming annual report — due on the first day of your company’s anniversary month each year (so it’s different for every company, based on when you formed). The fee is $60 minimum.
- Delaware LLC franchise tax — a flat fee ($400) due June 1 each year, with no annual report required. June 1, 2026 has already passed — the next one is June 1, 2027.
- Delaware corporation franchise tax + annual report — due March 1 each year, calculated from either authorized shares or assumed par value. March 1, 2026 has already passed — the next one is March 1, 2027.
These state dates run on their own schedule, separate from your federal filing. We track both for you, so nothing depends on you remembering two different calendars.
What we handle for you, and when
Here’s roughly how our year runs alongside yours:
- Weeks before your deadline — we reach out for the year’s transaction details (contributions, distributions, loans, income) so nothing is rushed at the last minute.
- We prepare your return — a pro-forma 1120 with 5472 or a 1120 (a 1065 for multi-member LLCs is coming soon) — based on what you send us.
- We file it on time. If you need more runway, you or your preparer file Form 7004 by the original deadline and you upload the confirmation in your dashboard before you pay; we track whichever deadline applies to your entity.
- You get a copy of everything filed, plus a submission record, so you always have your own paper trail alongside ours.
A quick founder checklist
- Know your entity type (single-member LLC, multi-member LLC, or C-Corp) — it decides your date.
- If you’re on extension, mark September 15 or October 15, 2026 on your calendar, whichever applies to you.
- If you owe tax and haven’t paid it, know that interest is running even with a filing extension in place.
- If you missed the original deadline with no extension filed, reach out rather than waiting.
- Send us your year’s transaction summary as soon as it’s ready — earlier is easier for everyone.
- If your state formation includes an annual report or franchise tax, note that date separately (it doesn’t follow the federal calendar).
None of this needs to live in your head. It’s built into every one of our federal tax plans: we track your specific deadline, prepare your return, and file it on time, every year, with copies and a submission record for your files.
