March 2026 Business Tax Deadlines: A Guide for Greater Boston Business Owners

While April 15th gets all the media attention, seasoned business owners in Braintree and Quincy know that March is the true heavy-lifting month for corporate compliance. March 2026 brings a wave of deadlines that affect everything from payroll transparency to the foundational tax returns for pass-through entities.

As your local accounting firm and IRS Enrolled Agents, we want to ensure you don't get caught off guard. Missing these dates doesn't just result in penalties; it often creates a bottleneck that prevents partners and shareholders from filing their personal returns on time.

March 2: The Paper Filing & Special Industry Deadline

If your business still handles specific filings on paper, or if you operate in the agriculture or hospitality sectors, the first Monday of the month is your cutoff.

Information Returns (Paper Filers)

While we strongly encourage electronic filing for efficiency and security, if you are filing paper Forms 1099 and the accompanying Form 1096 transmittals for 2025 payments, they must be postmarked by today. Note that this excludes Form 1099-NEC, which was due back in early February.

Healthcare Reporting (ACA)

Applicable Large Employers (ALEs) filing paper forms must submit:

  • Forms 1094-C and 1095-C: For employer-provided health insurance offers and coverage.
  • Forms 1094-B and 1095-B: For other providers of minimum essential coverage.

Additionally, this is the deadline to provide the recipient copies of Form 1095-C (to full-time employees) or Form 1095-B (to responsible individuals).

Specialized Industries

  • Farmers and Fishermen: File your 2025 Form 1040 and pay tax due to avoid penalties, unless you already paid estimated taxes by mid-January.
  • Gambling Winnings: File Form 1096 along with Copy A of Forms W-2G.
  • Large Food & Beverage Establishments: File Form 8027 (Tip Income) if filing on paper.

Note: If you file these information returns electronically, you generally gain an extension until March 31.

Business partners reviewing documents

March 16: The Pass-Through Entity Crunch

Because March 15, 2026, falls on a Sunday, the deadline for calendar-year partnerships and S corporations moves to Monday, March 16. This is the most critical date of the month for many of our real estate investor and small business clients.

One Accounting Tax® Since 2017
Call/Text: (617) 829-0928 or email service@oneaccountingtax.com to schedule an in-person consultation or video call with our Tax Advisors (IRS Enrolled Agent, EA) today. Serving Braintree, Quincy, and Greater Boston with full-service accounting—tax preparation, payroll, bookkeeping, and year-round tax planning.
Contact Our Local Tax Advisors Today!

Partnerships (Form 1065)

You must file the 2025 Form 1065 and issue Schedule K-1s to all partners. The K-1 is essential; your partners generally cannot file their personal income tax returns until they receive this document indicating their share of income, deductions, and credits.

S Corporations (Form 1120-S)

Similar to partnerships, S Corps must file Form 1120-S, pay any tax due, and provide Schedule K-1s to shareholders. If your bookkeeping needs cleanup or you are waiting on other data, we can file Form 7004 to request an automatic 6-month extension. However, remember that an extension to file is not an extension to pay—estimated taxes must still be deposited.

S Corporation Election (Form 2553)

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

Accountant working on business tax return

March 31: The Electronic Filing Deadline

The IRS incentivizes digital workflows by offering later deadlines. If you file electronically, March 31 is your due date for:

  • Forms 1099 (excluding 1099-NEC) and 1098.
  • Forms W-2G (Gambling winnings).
  • Forms 1094-C, 1095-C, 1094-B, and 1095-B (ACA Reporting).
  • Form 8027 (Tip Income).

Extensions and Special Situations

Disaster Area Relief: The IRS often provides automatic extensions for businesses located in designated disaster areas. If your Greater Boston area business has been impacted by severe weather events recognized by FEMA, your dates may differ.

You can verify current disaster declarations here:

Whether you need help finalizing your S Corp return, managing complex payroll deposits, or handling sales and meals tax compliance, proper planning is your best defense against audits. Contact our office in Braintree today to get your March filings in order.

One Accounting Tax® Since 2017
Call/Text: (617) 829-0928 or email service@oneaccountingtax.com to schedule an in-person consultation or video call with our Tax Advisors (IRS Enrolled Agent, EA) today. Serving Braintree, Quincy, and Greater Boston with full-service accounting—tax preparation, payroll, bookkeeping, and year-round tax planning.
Contact Our Local Tax Advisors Today!
Share this article...
Ask me anything! Our Ai Smart Bot Can Assist With Questions You May Have
If you'd prefer a call - click Contact Us Now below
Please fill out the form and our team will get back to you shortly The form was sent successfully