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Form 1120-S: U.S. Income Tax Return for an S Corporation

Definition: Form 1120-S is the annual IRS tax return filed by eligible S corporations to report income, deductions, gains, losses, and credits. Unlike C corporations, S corps are pass-through entities: profits/losses flow to shareholders’ personal returns via Schedule K-1, avoiding double taxation.

Why It Matters: Accurate 1120-S filings ensure proper shareholder basis, prevent IRS mismatches (CP2000 notices), and support deductions like Section 179 or QBI (20% qualified business income). Late filings trigger penalties ($220/month per shareholder for 2025), and errors can lead to audits or disallowed losses. If S corp issues have created personal tax debt or collection notices, Omni Tax Help reviews your 1120-S, prepares/amends with Form 1120-S K-1s, and resolves IRS disputes—optimizing pass-through benefits and protecting shareholder liability.

Key Schedules:

  • Schedule K: Summary of shareholders’ pro-rata shares.
  • Schedule L: Balance sheet.
  • Schedule M-1/M-2: Reconciliation of income and analysis of AAA (Accumulated Adjustments Account).

What to Do Next:

  1. File by March 15 (or extend to Sept 15 with Form 7004).
  2. Issue K-1s to shareholders by filing deadline.
  3. E-file recommended—we ensure compliance and basis tracking.

S corp status saves taxes when done right.

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