Form 2553 and Form 1120-S: What Must Be True First

17 October 2026 · Educational information · No affiliate links · 3 min read

General information, not tax, legal or financial advice. We are not the IRS. Check IRS.gov or a qualified tax professional. Sources read on October 17, 2026. Dates after 2026 are expected and amounts for 2026 returns may change. This page contains no affiliate links.

Short answer: per the 1120-S instructions, you file Form 1120-S if (a) the corporation elected to be an S corporation by filing Form 2553, (b) the IRS accepted the election, and (c) the election remains in effect. The instructions also say not to file Form 1120-S for any tax year before the year the election takes effect.

Checklist before March 15, 2027 (expected due date)

  1. Do you have confirmation that Form 2553 was accepted? The instructions say that if you did not receive notification of acceptance or non-acceptance within 2 months of filing (5 months if you asked for a letter ruling), follow up with the IRS at the number in the instructions.
  2. What effective date did you choose? The Form 2553 instructions explain which date to enter, including a first tax year in existence (earliest of the first date the corporation had shareholders, had assets, or began doing business).
  3. Is the election still in effect? Once made, it stays in effect until terminated.
  4. If the election ended during the year and the corporation reverted to a C corporation, the 1120-S instructions describe a short-year filing rule; read them or ask a professional.

When a timely election is filed

For a timely election, Form 2553 must generally be filed no more than 2 months and 15 days after the start of the tax year the election takes effect, or at any time during the preceding tax year (Instructions for Form 2553). For a calendar-year corporation electing S status starting January 1, 2027, that window is expected to run until March 15, 2027.

If the election was late or never made

If Form 2553 was not filed, or was filed late, the corporation may be entitled to relief for a late-filed election. Under the Form 2553 instructions (Rev. Proc. 2013-30), a corporation generally must show that it intended to be an S corporation, that it failed to qualify only because Form 2553 was not filed on time, that it had reasonable cause and acted diligently once it found the mistake, and that all shareholders reported income consistently with S status. In most cases Form 2553 must be filed within 3 years and 75 days of the effective date entered on line E, and the top margin of Form 2553 must read "FILED PURSUANT TO REV. PROC. 2013-30." If these requirements are not met, a private letter ruling (with a user fee) is generally needed. Talk to a tax professional before relying on this.

Dates

When the 1120-S is due: who files 1065 or 1120-S. Comparing with a C corporation: 1120-S vs 1120.

FAQ

Can an LLC elect S status? The 1120-S instructions say a corporation or other entity files Form 1120-S if it made and has had accepted an S election; see LLC classification. Eligibility rules were not read.

What we could not verify

Sources (official)