Form detail
IRS Form 1120-S
U.S. Income Tax Return for an S Corporation
Country
United States
Revision year
2024
Methods
paper, efile
Updated
2026-05-20
U.S. Income Tax Return for an S Corporation
Annual return for S corporations with pass-through treatment to shareholders.
Who must file: Small business corporations with a valid S election under Section 1362 in effect for the tax year.
Practical overview
Form 1120-S is an information return with K-1 distribution to shareholders. Common issues include shareholder basis tracking, reasonable compensation requirements for shareholder-employees, built-in gains tax for corporations that converted from C status within the five-year recognition period, and Accumulated Adjustments Account (AAA) tracking that affects distribution treatment.
Practical steps
- Verify the S election is valid and in effect for the tax year.
- Prepare Schedules K-1 for each shareholder with their pro-rata share of income, deductions, and credits.
- Compute and report any built-in gains tax or passive investment income tax.
- Track AAA, OAA, and accumulated E&P balances if the entity has prior C-corp years.
- File by March 15 for calendar-year filers with extension via Form 7004.
Due-date notes
March 15 for calendar-year S corporations.
Timing: March 15
Extension reference: Form 7004
Penalty snapshot
$245 per shareholder per month (2024) for late filing, plus separate penalties for K-1 reporting failures.
Related citations
Computed from the cross-reference graph. Links open the related entity on this site.
Cited by
- FormIRS 2553
Primary sources
- About Form 1120-SVerified 2026-05-20
- Instructions for Form 1120-SVerified 2026-05-20
Important disclaimer
This library is for general tax education only. Always verify filing obligations, due dates, and tax consequences against the cited primary source or with a qualified tax professional.