When is a partnership or S corporation tax return due?
The short answer
Monday, March 15, 2027 — one month before personal returns. Partnerships (including multi-member LLCs) file Form 1065, and S corporations file Form 1120-S. Tax season starts in January; March 15 is these returns' deadline, not the start of the season.
Why this date controls your personal return
Your business return produces each partner's Form K-1: the document that says how much each partner earned. Without their K-1, no partner can file their personal taxes. If the business is late, everyone is late — and each partner may also need their own personal extension.
What does being late cost?
The IRS penalty is $260 per partner, per month of delay (up to 12 months). A 2-partner LLC that files 3 months late pays $1,560 in penalties — for a return that doesn't even pay tax at the business level.
What about an extension?
With Form 7004, the extension is automatic until September 15, 2027. But note: an extension gives more time to file, not to pay — and partners receive their K-1 later, when the business finally files.
What to have ready
- Business bank statements (the full year)
- Your bookkeeping or income and expense records
- Each partner's information and ownership %
- Payroll reports and the 1099s you issued, if applicable
- The business's prior-year return
Frequently asked questions
Is my single-member LLC also due March 15?
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No. A single-member LLC usually files within its owner's personal return (Schedule C), due April 15. March 15 applies to multi-member LLCs (partnerships) and S corporations.
Does the partnership pay tax with the 1065?
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Generally no: the partnership reports, and each partner pays on their share in their personal return, using the K-1. That's why an on-time K-1 matters so much.
Can I extend only my personal return?
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If your K-1 hasn't arrived, many partners extend the business return (Form 7004) and also file a personal extension. We help you coordinate both.
What is a K-1 in plain words?
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It's a paper that says how much each partner earned, based on their share of the business. With that paper, each partner files their personal taxes. The business almost never pays the tax: each partner pays it.
Do I have to file Form 1065 even if my business made no money?
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Yes. Even if you earned nothing, you still have to file it — and the penalty for not filing shows up just the same.
Can I switch my LLC to an S corporation to save on taxes?
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Sometimes it helps, but it's not for everyone: you have to request it with a form before a certain date, and the owner has to start paying themselves a salary. We review it with your numbers before deciding.
March 15 comes fast. Message us on WhatsApp at 857-919-5069 and we'll prepare your business return early, without the stress.