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S corporation tax returns: Form 1120-S and California Form 100S

The S corporation's federal and California returns, plus K-1s for shareholders.

Agency
IRS + CA Franchise Tax Board
Who has to do it
S corporations (and LLCs that elected S-corp tax treatment).
If it's late
Per-shareholder monthly penalty federally, plus California penalties.
IRS Form 1120-S ↗California forms (FTB) ↗

Step by step

  1. IRS Form 1120-S

    IRS Form 1120-S ↗

  2. Export last year's profit and loss.

  3. Prepare Form 1120-S and California Form 100S.

  4. Send each shareholder a K-1.

  5. Or file extensions (IRS Form 7004; California is automatic).

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