Federal S corporation return

File Form 1120-S and give each shareholder a Schedule K-1, or file Form 7004 for a six month extension.

When: By the 15th day of the 3rd month after the fiscal year ends (March 15 for a calendar year).
Agency: IRS
Form: Form 1120-S
Applies to: S corporations in the United States.
If missed: $255 per shareholder for each month late, up to 12 months (the 2026 figure, adjusted yearly)
Source: www.irs.gov, read October 22, 2026

Jay explains

An S corporation files Form 1120-S by the 15th day of the third month after its fiscal year ends, March 15 for a calendar year. The return itself owes no tax in most cases, but the late filing penalty is charged per shareholder per month, so a late return with three owners costs more than most people expect.

Next dates

For a calendar year company. Weekend and holiday dates are moved to the next business day, as the IRS does.

March 15, 2027
March 15, 2028

Also in the federal calendar

Federal corporate income tax return Federal partnership return Business income on the owner's personal return Nonresident owner's US return, if one is owed Annual electronic notice for small exempt organizations Short annual return of an exempt organization Annual return of an exempt organization Annual return of a private foundation Exempt organization business income tax return Written acknowledgments to donors Corporate estimated tax payment Owners' estimated tax payments

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Your company's compliance calendar

Three answers to start. Refine it after.

What kind of organization is it?

An LLC's tax treatment decides which federal return it files. Choose the line that matches yours. Nonprofits are covered too.

State of formation

Employees

Count everyone on payroll. An S corporation's working owners are employees: they are paid a salary.

Where is it based? The state of the office, or of most of the people

A company based outside its state of formation is registered in both and files in both.

More about the company: other states, payroll, dates, abroad

Company name

Date registered in each other state

Optional. Some states key their report to the day you registered there rather than your date of formation; without it, the formation date stands in and the calendar says so.

Who runs payroll?

Fiscal year ends in

Date of formation

Needed for states that key filings to the anniversary of formation.

Annual revenue

Some taxes start at a revenue threshold.

We pay independent contractors We offer a retirement plan (401(k), SIMPLE, SEP)

Outside the United States We hold a bank or financial account outside the US A person or company outside the US owns 25% or more of it We own 10% or more of a company outside the US We pay people or companies outside the US

Each adds the FinCEN or IRS form that comes with it: the FBAR, Form 5472, Form 5471, Forms 1042 and 1042-S.

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