What is Form 1120-S?
Form 1120-S is the informational return an S corporation files to report income and each shareholder's share. The S corp usually pays no income tax itself — owners pay on their personal returns.
The 1120-S reports the S corp's profit and splits it among shareholders via K-1s, but the money-saving mechanic is payroll. Owner-employees take a W-2 salary (subject to payroll tax) and draw the rest as distributions that escape the 15.3% self-employment tax — the core reason profitable sole proprietors convert to S corps.
Who files it
Corporations and LLCs that elected S corporation status via Form 2553.
When it's due
Form 1120-S is generally due March 15 (calendar-year). Deadlines can move for weekends and holidays, so confirm the exact date for the current year on IRS.gov.
Key lines and parts
Here's what you'll actually fill in on Form 1120-S:
- Ordinary business income
- Deductions and wages
- Schedule K — shareholders' shares
- Schedule K-1 for each owner
How to file
File by March 15, issue a Schedule K-1 to each shareholder, and make sure owner-employees take reasonable W-2 wages.