S-Corp Election Deadline

The S-Corp election deadline is one of the most misunderstood rules in small-business taxation. Miss it by a day and your election does not take effect until the following tax year — costing some owners thousands of dollars in unnecessary self-employment tax. The good news: the IRS provides relief for most missed elections. The bad news: relief is not automatic, and it requires a separate filing with reasonable cause.

This guide is educational and is not a substitute for personalized tax or legal advice. If you are unsure how the deadline applies to your specific entity, please consult a CPA or tax attorney.

The general rule: 75 days from the start of the tax year

The statutory deadline for filing IRS Form 2553 to elect S-Corporation status is 2 months and 15 days after the start of the tax year in which the election is to take effect. In practice that works out to 75 days. Whether you are a brand-new LLC or an existing C-corporation switching its tax treatment, this is the window you have to act.

For calendar-year entities: March 15

Most small businesses use the calendar year as their tax year. For them, the math is simple: the tax year starts January 1, and 2 months and 15 days later is March 15. So the deadline to file Form 2553 and have the election effective for the current year is:

• March 15, 2026 for an election effective January 1, 2026
• March 15, 2027 for an election effective January 1, 2027

File after March 15 and the election will not take effect until January 1 of the next year — unless you qualify for late-election relief under Rev. Proc. 2013-30.

For newly formed entities: 75 days from "day one"

A brand-new LLC or corporation forming mid-year does not have to wait until the next March 15. New entities have 75 days from the earliest of these three events to file Form 2553 for their first tax year:

1. The date the entity first had shareholders or members.
2. The date the entity first acquired assets.
3. The date the entity began doing business.

So an LLC formed on August 1, 2026 has until approximately October 15, 2026 to elect S-Corp treatment effective for its first short tax year. Miss that window and the entity will be taxed as a partnership or sole proprietorship for the partial year, with S-Corp status starting January 1, 2027.

Fiscal-year filers

A small minority of S-Corps use a non-calendar fiscal year. For these entities, the deadline is still 2 months and 15 days from the start of the chosen fiscal year. Choosing a non-calendar tax year requires filing Part II of Form 2553 and demonstrating a valid business purpose, which the IRS scrutinizes. Most newly electing S-Corps simply use the calendar year because it is administratively simpler and avoids needing IRS approval.

Filing early is fine — and often smart

You can file Form 2553 well before the deadline. In fact, the IRS encourages it. The form may be filed any time during the prior tax year, or at any point during the current tax year up to the 75-day cutoff. Filing in late December or early January gives you cushion in case anything is wrong with the form, plenty of time to fix it, and an IRS confirmation (CP261 notice) before payroll setup begins.

What counts as "filed"

For mailed forms, the IRS uses the postmark date, not the date the form is received. Send Form 2553 by certified mail with return receipt, or by USPS Priority Mail with tracking, so you have proof of timely mailing. For faxed forms, the date and time printed on the IRS confirmation page is the filing date. Keep both records — the IRS occasionally loses paperwork, and you may need to prove timely filing months later.

What if I miss the deadline?

Missing the deadline is not the end of the world. Under Revenue Procedure 2013-30, the IRS grants automatic late-election relief if all of the following are true:

• The entity intended to be classified as an S-Corp as of the requested effective date.
• The only reason the election was not timely was a failure to file Form 2553 on time.
• The entity has not yet filed a tax return for the first year the election was intended.
• The election is being filed within 3 years and 75 days of the requested effective date.
• The entity has reasonable cause for missing the deadline (e.g., it was overlooked, it was filed but lost in the mail, an advisor failed to file it).

To request relief, the entity files Form 2553 with "FILED PURSUANT TO REV. PROC. 2013-30" written across the top, completes Part IV with a reasonable-cause statement, and obtains shareholder consents. Detailed steps are in our late S-Corp election guide.

Putting it together

• If you formed your entity in a prior year and use the calendar year: March 15 is your deadline for current-year effectiveness.
• If you formed your entity this year: 75 days from the day it began operations.
• If today is past either of those dates: file under Rev. Proc. 2013-30 with a reasonable-cause statement.
• If you want certainty, file early — the form can be sent any time during the prior tax year.

Entity IQ generates a pre-filled, IRS-ready Form 2553 from your business details and handles both timely and late elections under Rev. Proc. 2013-30, including the reasonable-cause statement. Want to see how much an S-Corp election would actually save you before filing? Run the numbers with our free S-Corp tax calculator.

This article is for educational purposes and is not legal or tax advice. Deadlines can interact with state-level filings, fiscal year elections, and existing IRS issues. Please consult a qualified CPA or tax attorney before filing.