Form 1120-S

The yearly return for S corporations

Due

March 15

Who files

Businesses

Source

IRS page for Form 1120-S →

Facts on this page come from IRS.gov (the Form 1120-S page was last updated by the IRS Jul 21, 2026); read by TaxScout Oct 22, 2026.

Who files Form 1120-S

A corporation files Form 1120-S to report its income, gains, losses, deductions and credits for any year its S corporation election is in effect. The election is made on Form 2553, and the IRS must accept it.

When it is due

March 15 for calendar-year filers.

Due by the 15th day of the 3rd month after the tax year ends. Calendar-year 2025 returns are due March 16, 2026, because March 15 is a Sunday. Weekend and holiday due dates move to the next business day, and Form 7004 requests an extension, generally by the regular due date.

What the IRS says

Do not file Form 1120-S for any tax year before the S election takes effect. Source
Schedule K-1 (Form 1120-S) reports each shareholder's share of income, deductions and credits. Source
The penalty for not giving a correct Schedule K-1 on time is $340 per schedule, unless there is reasonable cause. Source

Preparers who say they handle Form 1120-S

Each city page lists firms whose own website names this return. TaxScout read those sites; it does not rank firms by payment.

Charlotte, NC42 firms Raleigh, NC25 firms Greensboro, NC13 firms Boston, MA10 firms Durham, NC10 firms Matthews, NC9 firms Winston Salem, NC9 firms Huntersville, NC7 firms Asheville, NC7 firms Princeton, NJ7 firms Westwood, MA6 firms Wilmington, NC6 firms Cary, NC5 firms Woburn, MA5 firms Toms River, NJ5 firms Waxhaw, NC5 firms Jersey City, NJ5 firms Morristown, NJ4 firms

What preparers charge

Massachusetts · Form 1120-S (S corporation)$1,254

North Carolina · Form 1120-S (S corporation)$945

New Jersey · Form 1120-S (S corporation)$1,359

Average fees reported by preparers in the National Society of Accountants 2020-2021 Income and Fees Survey, State Averages (published 2020). Fees today are likely higher; ask the firm for its own quote.

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Common questions

Who files Form 1120-S?

When is Form 1120-S due?

March 15 for calendar-year filers. Due by the 15th day of the 3rd month after the tax year ends. Calendar-year 2025 returns are due March 16, 2026, because March 15 is a Sunday. Weekend and holiday due dates move to the next business day, and Form 7004 requests an extension, generally by the regular due date.

Do I need a CPA for Form 1120-S?

Not always. A CPA, an Enrolled Agent or another paid preparer with a PTIN can prepare it. Firms listed for this form say on their own websites that they handle it; TaxScout does not rank them by payment.

Related forms

All forms →

Form 7004 · More time to file a business returnWith its return

Not tax advice. TaxScout is not the IRS. Due dates and thresholds above are quoted from the IRS pages linked next to them and change from year to year; the IRS instructions for your tax year control.