March 16 Is the S-Corp and Partnership Tax Deadline: What You Need to Know for 2026

Disclaimer: This article is for general educational purposes and does not constitute tax advice. Tax outcomes depend on your specific facts and circumstances. Consult a licensed CPA before making filing decisions.

Updated July 2026: The original March 16, 2026 deadline has passed. If you filed Form 7004 on time, your extended S-Corp/partnership deadline is September 15, 2026 - do not wait until September to start. If you missed the deadline entirely, jump to "What Are My Options If I Missed the March 16 Deadline?" - penalties accrue monthly.

In This Article

1. What Does the March 16, 2026 S-Corp and Partnership Tax Deadline Cover?
2. Why Does the March 16 S-Corp and Partnership Deadline Matter More Than April 15?
3. What Tax Forms Are Actually Due on March 16 for S-Corps and Partnerships?
4. What New Jersey-Specific Requirements Apply to S-Corps and Partnerships on March 16?
5. What Should I Do If I Can't File My S-Corp or Partnership Return by March 16?
6. What Are the Late Filing Penalties for S-Corp and Partnership Returns?
7. What Should S-Corp and Partnership Owners Do Before the March 16 Deadline?
8. What Are My Options If I Missed the March 16 S-Corp or Partnership Deadline?
9. Frequently Asked Questions
10. Ready to File With Confidence?

What Does the March 16, 2026 S-Corp and Partnership Tax Deadline Cover?

If you own an S-Corporation or a partnership, March 16, 2026 is one of the most important dates on your tax calendar. This is the original due date for:

• Form 1120-S: the U.S. Income Tax Return for an S Corporation
• Form 1065: the U.S. Return of Partnership Income
• Schedule K-1s: which must be distributed to all shareholders (S-Corps) or partners (partnerships) by this same date

Note: March 15 is the statutory deadline, but it falls on a Sunday in 2026, so the actual deadline shifts to Monday, March 16, 2026.

Why Does the March 16 S-Corp and Partnership Deadline Matter More Than April 15?

Most individual taxpayers think of April 15 as "tax deadline day." But for pass-through entity owners, March 16 is more consequential, and missing it has downstream effects on your personal return.

Here's why: S-Corps and partnerships file informational returns and issue Schedule K-1s that report each owner's share of income, deductions, and credits. Your personal return (Form 1040) cannot be completed accurately until you receive your K-1. This means:

1. If your S-Corp or partnership files late, you can't complete your personal return on time.
2. You may be forced to file a personal extension (Form 4868) even if your personal return is otherwise ready.
3. Late K-1s are a leading cause of amended individual returns.

The March 16 deadline exists specifically to give pass-through entity owners enough time to complete their personal returns by April 15.

What Tax Forms Are Actually Due on March 16 for S-Corps and Partnerships?

Form 1120-S (S-Corporations)

Form 1120-S reports the S-Corporation's income, deductions, and credits for the year. The return itself does not result in a tax payment (S-Corps are pass-through entities; income is taxed at the shareholder level). However, the return must be filed or extended on time, and Schedule K-1s must be distributed to all shareholders.

Key items on 1120-S:

• Ordinary business income or loss
• Rental income and other separately stated items
• Section 179 deductions and bonus depreciation
• Shareholder W-2 wages (reasonable compensation)
• Accumulated Adjustments Account (AAA)

Form 1065 (Partnerships and Multi-Member LLCs)

Form 1065 is the informational return for general partnerships, limited partnerships, LLPs, and multi-member LLCs taxed as partnerships. Like the 1120-S, no entity-level tax is paid with the return (unless the partnership has New Jersey BAIT obligations).

Key items on 1065:

• Ordinary income or loss from partnership activities
• Guaranteed payments to partners
• Section 704(b) allocations if partners have special allocation agreements
• Self-employment income allocations for general partners

Schedule K-1s

This is the document each owner receives from the entity. It shows your individual share of income, deductions, and credits. K-1s must be distributed by the same March 16 deadline.

If you have multiple K-1s (e.g., you're a partner in multiple partnerships or an investor in several S-Corps), all of them should be in your hands before you can finalize your personal return.

What New Jersey-Specific Requirements Apply to S-Corps and Partnerships on March 16?

New Jersey has its own pass-through entity requirements that align with (but are not identical to) federal due dates.

NJ-1065 (Partnerships)

New Jersey requires partnerships to file Form NJ-1065 by the 15th day of the 4th month following the close of the tax year - April 15, 2026 for calendar-year filers (NOT March 15/16; NJ-1065 is NOT on the federal partnership deadline). The NJ-1065 includes a New Jersey Gross Income Tax prepayment for non-resident partners. Partnerships needing more time file Form PART-200-T for a 5-month extension to September 15, 2026 (Form NJ-630 - the Gross Income Tax extension used for NJ-1040/NJ-1041 filings - is not used for partnerships).

NJ BAIT Election

The New Jersey Business Alternative Income Tax (BAIT) allows pass-through entities to elect to pay income tax at the entity level. The TY2025 BAIT election had to be made via the NJ Division of Taxation's PTE File and Pay System before March 16, 2026 - the original due date of the 2025 PTE-100 (the 15th day of the third month after the close of the tax year, rolled from Sunday March 15). For TY2026, the election must be made before March 15, 2027. The election is NOT made on the entity tax return. The BAIT election can significantly benefit partners and shareholders by effectively bypassing the federal SALT deduction cap.

NJ CBT-100S (S-Corporations)

S-Corporations in New Jersey must file Form CBT-100S by the 15th day of the month following the federal due date - April 15, 2026 for TY2025 calendar-year filers (one month after the federal March 16, 2026 deadline). The 6-month extension is requested on Form CBT-200-T and extends the return to October 15, 2026. Unlike federal S-Corp treatment (where no entity-level tax is owed), New Jersey imposes a tiered minimum CBT tax ($375 to $1,500 based on NJ gross receipts) and potentially additional CBT tax on S-Corps. This is a common surprise for business owners who assume their S-Corp has no state-level tax obligations.

NJ CBT-100 (C-Corporations)

NJ C-Corporations file Form CBT-100 by the 15th day of the 5th month after the close of the tax year - May 15, 2026 for TY2025 calendar-year filers (one month after the federal C-Corp April 15 deadline). The 6-month extension via Form CBT-200-T runs to November 15, 2026.

What Should I Do If I Can't File My S-Corp or Partnership Return by March 16?

File an extension. The IRS automatically grants a 6-month extension if you file Form 7004 by March 16. For S-Corps, this extends the deadline to September 15, 2026. For partnerships, the same: September 15, 2026.

Important: An extension of time to file is not an extension of time to pay. If your entity owes any taxes (some S-Corps owe built-in gains tax or excess net passive income tax), those amounts are still due by March 16. Underpayment can result in penalties and interest.

NJ extension: CBT-200-T is used for both CBT-100S and CBT-100 (6-month extension). For a partnership (NJ-1065), New Jersey honors the federal Form 7004 extension only when no NJ partnership filing fee or nonresident-partner tax is due (enclose a copy of the federal 7004); when a fee or nonresident-partner tax is owed, file PART-200-T with at least 80% of the balance paid by the original due date (5-month extension to September 15). Form NJ-630 is the Gross Income Tax extension for individual and fiduciary returns (NJ-1040/NJ-1041), not for partnerships. All NJ extensions must be filed with the appropriate form by the original due date.

What Are the Late Filing Penalties for S-Corp and Partnership Returns?

The IRS imposes penalties for late filing of pass-through entity returns:

• Form 1065 (Partnerships): $255 per partner, per month (up to 12 months maximum) for TY2025 returns filed in 2026, per Rev. Proc. 2024-40 / 2025-32 inflation adjustment. So a 3-partner LLC that files 3 months late could face $2,295 in penalties.
• Form 1120-S (S-Corps): $255 per shareholder, per month (up to 12 months maximum) for TY2025 returns filed in 2026.

These penalties can add up quickly for multi-partner arrangements. Filing an extension eliminates the late-filing penalty, even if you can't pay what's owed.

What Should S-Corp and Partnership Owners Do Before the March 16 Deadline?

If you own an S-Corp or partnership and have not yet engaged a CPA for your 2025 return, here's what to do right now:

1. Gather your 2025 financials. P&L statement, balance sheet, and bank reconciliations for the full year.
2. Compile payroll records. W-2s for all employees, including owner-employees (S-Corp shareholders who received wages).
3. Pull last year's return. Your 2024 1120-S or 1065 provides carry-forward items, basis schedules, and depreciation records.
4. Contact a CPA now. If March 16, 2026 has already passed and you filed Form 7004 on time, your extended deadline is September 15, 2026 - do not wait until September to start. If you missed the deadline without an extension, see the next section: penalties accrue monthly, so file as soon as possible.

Monaco CPA handles S-Corp and partnership returns for New Jersey small businesses. Contact us to discuss your situation.

What Are My Options If I Missed the March 16 S-Corp or Partnership Deadline?

If you missed the March 16 deadline for your S-Corp or partnership return, file Form 7004 for an automatic 6-month extension (new deadline: September 15, 2026). The extension covers the return only, not tax payments. Any tax owed was still due March 16.

If you missed the deadline to elect S-Corp status for 2026, you may qualify for late election relief under Rev. Proc. 2013-30. The IRS allows late Form 2553 filings within 3 years and 75 days of the intended effective date if you had reasonable cause, intended S-Corp treatment from the effective date, and you and all shareholders reported income consistently with S-Corp status. If you missed the window, Use the contact form to determine if you qualify.

Use the S-Corp calculator to see if the election makes sense for your income level.

Greg Monaco, CPA, MBA is the founder of Gregory Monaco, CPA LLC, a virtual CPA practice based in Livingston, NJ. His practice focuses on small business tax compliance, S-Corp elections, and NJ tax planning. Member of AICPA and NJCPA.

Frequently Asked Questions

Ready to File With Confidence?

Tax rules change frequently. If anything in this guide applies to your situation, a quick review with a CPA can prevent costly mistakes. Greg Monaco is a NJ-licensed CPA (License #20CC04711400). Greg remains responsible for every engagement and reviews, approves, and signs all client-facing work. Trained staff may assist under his direct supervision and confidentiality procedures.

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