March 2026 Business Due Dates: S Corps, Partnerships, and Information Returns

While January and February often focus on getting W-2s out the door and starting individual returns, March is arguably the busiest month of the year for business entities. If you operate a partnership or an S Corporation, the clock is ticking on your primary tax return. Additionally, businesses that still file paper information returns face immediate deadlines early in the month.

Keeping your entity compliant now prevents significant penalties later and ensures your partners or shareholders receive the documents they need to file their own personal returns. Here is your roadmap for March 2026 business deadlines.

March 2: The Paper Filing & Special Industry Deadline

Because March 1, 2026, falls on a Sunday, the following deadlines move to Monday, March 2.

Information Returns (Paper Filings)

If you have not yet transitioned to electronic filing, today is the deadline to file government copies of information returns (Forms 1099) and transmittal Forms 1096 for payments made in 2025. Note that this applies to returns other than the 1099-NEC, which was due back in early February.

Health Coverage Reporting (ACA Forms)

Applicable Large Employers (ALEs) must file paper Forms 1094-C and 1095-C with the IRS. Other providers of minimum essential coverage must file paper Forms 1094-B and 1095-B.

Critically, you must also provide the actual forms to the recipients by this date:

  • ALEs: Provide Form 1095-C to full-time employees.
  • Coverage Providers: Provide Form 1095-B to responsible individuals.

Note: If you file these forms electronically, your filing deadline with the IRS extends to March 31.

Farmers and Fishermen

If you did not pay your estimated tax by January 15, you must file your 2025 income tax return (Form 1040 or 1040-SR) and pay all tax due by March 2 to avoid penalties. If you made that January payment, you have until April 15.

Family business owners discussing finances

March 16: The Pass-Through Entity Deadline

This is the big one for pass-through entities. Timely filing here is essential because the K-1s generated by these returns are required for the personal tax returns of every partner and shareholder.

Partnerships (Form 1065)

Partnerships must file their 2025 calendar year return (Form 1065). You must provide each partner with their Schedule K-1 and, if applicable, Schedule K-3. These forms detail the partner's share of income, deductions, and credits.

Need more time? If the books aren't closed yet, file Form 7004 to request an automatic 6-month extension. This pushes the filing deadline to September 15, but remember: the partners cannot file their personal returns until you finalize the partnership return.

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S Corporations (Form 1120-S)

S Corps must file the 2025 calendar year income tax return (Form 1120-S) and pay any tax due. Similar to partnerships, you must provide each shareholder with their Schedule K-1 and any applicable Schedule K-3.

To request a 6-month extension, file Form 7004 and pay any estimated tax owed. This extends the filing (and K-1 generation) deadline to September 15.

S Corporation Election (Form 2553)

If you are an LLC or C Corp and want to be taxed as an S Corp for the 2026 calendar year, you must file Form 2553 by March 16. Missing this date generally means your S Corp status won't take effect until 2027, unless you qualify for specific relief.

Monthly Tax Deposits

For businesses following the monthly deposit rule, deposit the tax for payments made in February regarding:

  • Social Security, Medicare, and withheld income tax.
  • Non-payroll withholding.

Close up of business calculations and tax forms

March 31: The Electronic Filing Deadline

The IRS encourages electronic filing by offering a later deadline for various information returns. If you file electronically, March 31 is your due date for:

  • Forms 1099 and 1096: General information returns (excluding the 1099-NEC).
  • Forms W-2G: Gambling winnings.
  • ACA Forms: 1094-C, 1095-C, 1094-B, and 1095-B.
  • Form 8027: Employer’s Annual Information Return of Tip Income and Allocated Tips.

Standard Rules & Disaster Relief

Weekends & Holidays: As always, if a due date falls on a Saturday, Sunday, or legal holiday, the deadline is automatically pushed to the next business day.

Disaster Area Extensions: If your business is located in a federally designated disaster area, you may have extra time to file. We monitor these announcements closely, but you can also verify the status of your area using the official resources below:

March is a pivotal month for business compliance. Whether you need to file an extension for your S Corp or ensure your 1099s were accepted, we are here to help you navigate the complexity. Please reach out if you need assistance finalizing your returns.

Let’s Start a Conversation.
You can count on us for professional guidance along with timely, and reliable tax services. If you’re ready to get started, or just want to start a conversation, then click below.
Learn More
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