The S corp election deadline is the 15th day of the third month of the tax year you want the election to take effect. For a calendar-year business in 2026, that falls on Monday, March 16, because March 15 is a Sunday. File Form 2553 by that date and the election covers the whole 2026 tax year. File even one day late and, absent relief, the election is bumped to 2027 and your business is taxed under its default classification for all of 2026.
The Two Filing Windows
Federal law gives you two windows to file Form 2553 for a given tax year.1Office of the Law Revision Counsel. 26 USC 1362 – Election; Revocation; Termination
- Anytime during the prior tax year. Filing at any point during 2025 makes the election effective for the 2026 tax year.
- On or before the 15th day of the third month of the tax year itself. For calendar-year entities that is normally March 15, and March 16 in 2026.
The form cannot be filed electronically. It has to be mailed or faxed to the IRS service center listed in the Form 2553 instructions for the state where the corporation’s principal office sits. Keep a certified mail receipt or fax confirmation. That receipt is your evidence of timely filing if the IRS ever questions the date, and the IRS typically takes about 60 days to send back a formal acceptance letter (CP261).
When the Clock Starts for a New Business
A brand-new entity gets the same two-month-and-15-day window, but the clock does not start on the date shown on your incorporation paperwork. It starts on the earliest of three events: the corporation had shareholders, it acquired assets, or it began doing business.2Internal Revenue Service. Instructions for Form 2553
That distinction matters. If you incorporate in October but do not issue stock or begin operating until November, the November date triggers the clock. And if the resulting short first tax year runs two and a half months or less, the election just needs to be filed by the end of that short tax year to count as timely.
What Happens if You File Late
An election filed after the 15th day of the third month, but on or before that same date in the following tax year, is treated as effective for the next tax year.1Office of the Law Revision Counsel. 26 USC 1362 – Election; Revocation; Termination A calendar-year entity that files in April 2026 lands its effective date on January 1, 2027. For the entire 2026 tax year, the business is taxed under whatever its default classification was: C corporation for a corporation, partnership for a multi-member LLC, sole proprietorship on Schedule C for a single-member LLC.
An election also gets bumped to the following year if the corporation failed any eligibility requirement on any day of the tax year before the election was filed, or if a shareholder who held stock during that pre-election period did not consent. This catches situations where a disqualifying shareholder sold out and the new ownership group then tried to elect retroactively.
Late Election Relief
Missing the deadline is not necessarily fatal. Revenue Procedure 2013-30 lets IRS campus offices grant retroactive relief without the cost of a private letter ruling. Four conditions all have to be met:3Internal Revenue Service. Revenue Procedure 2013-30
- The entity intended to be an S corporation as of the requested effective date.
- The request is filed within three years and 75 days of that intended effective date.
- The only defect was the late filing. If the entity also failed an eligibility requirement, this relief does not apply.
- The entity has reasonable cause for missing the deadline and acted diligently to correct it once the mistake was discovered.
The filing itself is a completed Form 2553 with a note at the top that relief is being requested under Rev. Proc. 2013-30, a reasonable cause statement signed under penalties of perjury, and evidence that shareholders have been reporting their income consistently with S corporation treatment since the intended effective date. That last piece matters. If shareholders filed their personal returns as though they held C corporation stock, reporting only dividends received rather than a share of corporate income, the IRS will question whether S status was truly intended.4Internal Revenue Service. Late Election Relief
When Rev. Proc. 2013-30 Isn’t Available
Past three years and 75 days, or when the conditions above aren’t met, the remaining option is a private letter ruling. The user fee alone for a ruling request under Section 1362(b)(5) is $14,500, reduced to $9,775 if gross income is under $10 million and $3,450 if gross income is under $400,000.4Internal Revenue Service. Late Election Relief Add attorney fees on top of that, and the total often exceeds whatever tax savings the election would have delivered. A PLR is a last resort.
The LLC Shortcut
LLCs are the most common entity type making this election, and the process contains a useful shortcut. By default, a single-member LLC is taxed as a sole proprietorship and a multi-member LLC as a partnership. Neither is a corporation, so becoming an S corporation would ordinarily require electing corporate treatment on Form 8832 first, then filing Form 2553.
The IRS lets you skip the first step. An eligible LLC can file Form 2553 alone, and the S election itself causes the entity to be treated as a corporation as of the election’s effective date.2Internal Revenue Service. Instructions for Form 2553 One form, one effective date, no risk of the two elections falling out of sync.
An LLC that misses the Form 2553 deadline stays under its default classification for the entire tax year. Not catastrophic, but it delays the intended tax treatment by a full year.
Eligibility to Confirm Before You File
A timely-filed Form 2553 does nothing if the entity does not qualify. The IRS requires the corporation to fit the definition of a small business corporation:5Office of the Law Revision Counsel. 26 USC 1361 – S Corporation Defined
- Organized in the United States.
- No more than 100 shareholders. A married couple and their estates count as one shareholder, and the same treatment extends to members of a single family going back up to six generations.
- Shareholders limited to individuals, certain trusts, and estates. Partnerships, other corporations, and nonresident aliens cannot own shares.
- One class of stock. All outstanding shares must carry identical rights to distributions and liquidation proceeds. Differences in voting rights alone are fine.
The one-class-of-stock rule catches more businesses than owners expect. A shareholder agreement that gives one owner a priority distribution or a guaranteed payment can inadvertently create a second class and void the election. Straight debt, such as a shareholder loan with a fixed interest rate and no conversion feature, gets a statutory safe harbor.
Every shareholder who owns stock on or before the election date has to sign the consent section of Form 2553. So does any former shareholder who held stock earlier in the same tax year. A single missing signature invalidates the election for that year. If a trust holds stock, it must independently qualify as an eligible shareholder, and QSSTs and ESBTs each require their own separate election filed within two months and 16 days after the stock transfer. Missing that trust-level deadline can terminate the corporation’s S status.
State Filings Are Separate
The S corporation election is a federal designation. Most states recognize it automatically, but a handful, New York being the most prominent, require a separate state-level election. Skip the state filing in one of those states and the entity can be treated as a C corporation for state tax purposes even while being an S corporation federally. Some states also impose minimum annual taxes or franchise fees on S corporations regardless of income. Check your state’s rules before you file, not after the first state tax bill arrives.