S Corp Election Deadline: Windows, Late Relief, and Form 2553

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 targeting the 2026 tax year, that date is March 16, 2026, because March 15 falls on a Sunday. You can also file at any point during the prior tax year and have the election apply to the next one. The election is made on IRS Form 2553, and every shareholder must consent before it goes in.¹

The Two Filing Windows

Federal law gives you two separate chances to file Form 2553 for a given tax year.¹

Any time during the prior tax year. Filing anywhere in 2025 makes the election effective for the 2026 tax year.
On or before the 15th day of the third month of the tax year you want to be an S corporation. For a calendar-year entity in 2026, that is March 16.

Either window works. There is no advantage to waiting until the second one, and plenty of risk, because a single missed signature or wrong shareholder detail on a March filing leaves no time to fix the problem before the clock runs out.

When the Clock Starts for a New Business

A brand-new entity gets the same two-and-a-half-month window, but the clock starts on the earliest date the corporation had shareholders, acquired assets, or began doing business. Whichever of those three events comes first marks the beginning of the entity’s first tax year.²

Formation paperwork doesn’t always align with when business activity starts. Incorporate in October but issue stock in November, and the November date triggers the clock. If that first tax year turns out to be shorter than two and a half months, filing by the end of the short year counts 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.¹ A calendar-year entity that files in April 2026 would see its S status start on January 1, 2027. For all of 2026, the business would be taxed under whatever its default classification is: C corporation for a corporation, partnership for a multi-member LLC, sole proprietorship for a single-member LLC.

A late-filed election also rolls to the next year if the entity failed any eligibility requirement on any day before the filing date during the current tax year, or if any shareholder who held stock before the election date did not consent. That rule catches attempts to clean up a disqualifying situation (a nonresident alien shareholder, say) and then file retroactively as if the problem never existed.

Late Election Relief Under Rev. Proc. 2013-30

Missing the deadline isn’t necessarily the end of the matter. The IRS offers a streamlined process under Revenue Procedure 2013-30 that lets IRS campus offices grant retroactive relief without a formal ruling request. All four of these conditions must be met:³

The entity intended to be classified as an S corporation as of the requested effective date.
The request is filed within three years and 75 days of the intended effective date.
The only defect was the late filing. The entity would have qualified for S status except for the missed deadline.
The entity has a reasonable explanation for missing the deadline and acted quickly once the mistake was discovered.

The filing itself is a completed Form 2553 marked at the top with a statement that relief is being requested under Rev. Proc. 2013-30, a reasonable cause statement signed under penalties of perjury, and evidence that the shareholders have been reporting their income consistently with S corporation treatment since the intended effective date. That last point matters. If shareholders filed personal returns as if they were C corporation shareholders, reporting only dividends rather than their pro-rata share of corporate income, the IRS will doubt that S status was actually intended.⁴

When Only a Private Letter Ruling Will Work

If more than three years and 75 days have passed since the intended effective date, or the entity otherwise falls outside Rev. Proc. 2013-30, the remaining option is a Private Letter Ruling. Under the current fee schedule, a ruling request for a late election under Section 1362(b)(5) costs $14,500. Reduced fees apply to smaller businesses: $9,775 if gross income is under $10 million, and $3,450 if gross income is under $400,000.⁴ Add professional fees for preparing the request and the cost can exceed the tax savings the election would have produced. A PLR is a last resort.

Eligibility Still Has to Be There

No deadline rule, timely or late, helps an entity that doesn’t qualify in the first place. The corporation must be domestic, have no more than 100 shareholders, limit ownership to individuals, certain trusts, and estates (no partnerships, corporations, or nonresident aliens), and have only one class of stock based on distribution and liquidation rights.⁵ Differences in voting rights alone are fine. Shareholder agreements that give some owners priority distributions quietly create a second class and void the election.

One eligibility trap is worth flagging because it sits outside the Form 2553 process entirely. If a trust holds S corporation stock, it must independently qualify as an eligible shareholder, usually through a Qualified Subchapter S Trust (QSST) or Electing Small Business Trust (ESBT) election. Each has its own separate filing deadline (two months and 16 days after the stock is transferred to the trust), and missing it can terminate the corporation’s S status for everyone.

How LLCs Hit the Deadline

LLCs are the most common filers, and there is a shortcut worth knowing. By default, an LLC is not a corporation at all: a single-member LLC is taxed as a sole proprietorship, a multi-member LLC as a partnership. To become an S corporation, an LLC would ordinarily have to first elect corporate treatment on Form 8832 and then elect S status on Form 2553.

The IRS lets eligible LLCs skip Form 8832. Filing Form 2553 alone automatically treats the LLC as a corporation as of the S election’s effective date.² One form, one deadline, no risk of mismatched effective dates between two filings.

Filing the Form on Time

Form 2553 cannot be filed electronically. It must be mailed or faxed to the IRS service center that handles the state where the corporation’s principal office is located; the addresses and fax numbers are in the form’s instructions. Keep proof of submission. A certified mail receipt or a fax confirmation is your evidence that the form went in on time if the IRS later questions it. Processing typically takes about 60 days, after which the IRS mails an acceptance letter (CP261) confirming the S corporation status and its effective date. If 60 days pass without a response, the IRS Business and Specialty Tax Line can confirm whether the election was received.

The place elections most often fall apart is shareholder consent. Every person who owned shares at any point during the tax year before the election date, including former shareholders, must sign and provide name, address, Social Security number, number of shares, and acquisition date. One missing signature invalidates the election for that tax year, and by the time the IRS flags it the original deadline is usually long gone.

1
Office of the Law Revision Counsel. 26 USC 1362 – Election; Revocation; Termination
2
Internal Revenue Service. Instructions for Form 2553
3
Internal Revenue Service. Revenue Procedure 2013-30
4
Internal Revenue Service. Late Election Relief
5
Office of the Law Revision Counsel. 26 USC 1361 – S Corporation Defined