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Your Business Tax Roadmap for March 2026

While the general public often fixates on April 15, experienced business owners know that March is often the true finish line for entity tax compliance. For our clients here in Gilbert and the greater Arizona area, this month is critical for finalizing partnership returns, S Corporation filings, and wrapping up information reporting.

Missing these dates can lead to significant penalties, particularly regarding late filing fees for flow-through entities. Below is your detailed timeline for keeping your business compliant this month.

March 2: The Paper Filing Deadline

Because March 1 falls on a Sunday in 2026, the deadline for several paper-filed returns pushes to Monday, March 2. While we strongly encourage electronic filing for efficiency and tracking, businesses still filing paper forms must adhere to this date.

Information Returns (Forms 1099 & 1096)

If you are filing paper copies with the government, today is the deadline for Forms 1099 and the transmittal Form 1096 for payments made in 2025 (excluding the 1099-NEC, which was due previously). This also applies to payers of gambling winnings filing Form 1096 and W-2G.

ACA Reporting for Applicable Large Employers

Applicable Large Employers (ALEs) filing paper forms must submit Forms 1094-C and 1095-C to the IRS. Other providers of minimum essential coverage must file Forms 1094-B and 1095-B. Please note: if you file these electronically, your deadline is automatically extended to March 31.

Farmers and Fishermen

If you did not pay your estimated tax by January 15, your 2026 income tax return (Form 1040) is due today to avoid penalties.

Business partners reviewing documents

March 16: The Big Business Deadline

This is the most significant date on the calendar for flow-through entities. Since March 15 falls on a Sunday, the deadline moves to Monday, March 16.

Partnerships (Form 1065) & S Corporations (Form 1120-S)

Calendar year Partnerships and S Corporations must file their 2025 tax returns today. Equally important, you must provide Schedule K-1s to your partners or shareholders. These individuals generally cannot file their personal income tax returns until they receive these K-1s.

Need more time? If your books aren't quite ready—perhaps you are waiting on financials or corrections—you must file Form 7004 by today to request an automatic 6-month extension. Remember, an extension to file is not an extension to pay. If your S Corp owes taxes, you should estimate and pay them now to avoid interest.

S Corporation Election (Form 2553)

If you operate an LLC and want to be taxed as an S Corporation for the 2026 tax year to potentially optimize your self-employment taxes, you must file Form 2553 by this date. Filing late generally means the election won't take effect until 2027, unless reasonable cause is established.

March 31: Electronic Filing Deadlines

As the month closes, the window shuts for electronic information reporting. If you file electronically (which Martinez & Shanken PLLC highly recommends for accuracy and speed), this is your due date for:

  • Forms 1099, 1098, and W-2G: Filed with the IRS.
  • ACA Forms: Electronic filing of Forms 1094-C, 1095-C, 1094-B, and 1095-B.
  • Tip Reporting: Electronic filing of Form 8027 for large food and beverage establishments.
Tax forms organized on a desk

Important Administrative Notes

Weekend and Holiday Rule

When a tax deadline falls on a Saturday, Sunday, or legal holiday, the due date shifts to the next business day. This is why you see the primary business deadlines falling on March 2 and March 16 this year.

Disaster Area Extensions

The IRS frequently offers relief for businesses located in federally declared disaster areas. If your records or operations were affected by severe weather events, check the FEMA and IRS websites to see if your deadlines have been postponed.

Need Help with Your Extension?

If March 16 is approaching too fast, don't panic, but do act. Filing an extension is a standard procedure that prevents late-filing penalties. Contact Martinez & Shanken PLLC to ensure your extensions are filed correctly or to discuss your S Corp election status.

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1560 W Warner Rd Suite 200
Gilbert, Arizona 85233
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