S election, 83(b) and the other start-up deadlines
A few filings in the first weeks cannot be undone if you miss them. Here is each one, its deadline, who needs it, and what late relief exists.
Prepared by Prem Tax and Accounting Corp. Last checked against official sources on October 9, 2026.
The deadlines
| Filing | Deadline | Notes |
|---|---|---|
| EIN (Form SS-4 or online) | Right after formation, before payroll or a bank account | Free. A responsible party with an SSN or ITIN can apply online; a business located outside the U.S. cannot use the online tool |
| S corporation election (Form 2553) | Within 2 months and 15 days of the start of the tax year | All shareholders sign. Late relief within 3 years and 75 days |
| Section 83(b) election | Within 30 days of the stock transfer | No late relief. Mail it with proof and keep a copy |
| Entity classification (Form 8832) | Up to 75 days before to 12 months after the filing | Needed only for a classification election without Form 2553 |
| Illinois registrations (IDOR, IDES) | Before the first sale or paycheck | Sales tax, withholding and unemployment insurance |
| Beneficial ownership (BOI) report | Not required for U.S. companies since August 14, 2026 | Foreign companies registered in the U.S. still report |
S corporation election: who qualifies
- A domestic corporation, or an LLC electing corporate treatment.
- No more than 100 shareholders (a family can count as one).
- One class of stock.
- Shareholders must be individuals, estates and certain trusts and exempt organizations. Nonresident aliens cannot be shareholders.
- Not a bank, insurance company or DISC.
Section 83(b): the one that cannot be fixed
Receiving stock that is subject to vesting is not taxed until it vests, unless you elect. The election makes you taxable on the value at the transfer date (usually very little for a new company), so later growth is taxed as capital gain when you sell instead of as pay when it vests. The deadline is 30 days from the transfer, with no extension.
Common questions
When must the S election be filed?
No more than 2 months and 15 days after the beginning of the tax year the election is to take effect, or at any time during the tax year before. For a new corporation, the year begins when it first has shareholders, assets, or starts business, whichever is earliest.
What if I miss the S election deadline?
Late election relief is available if you have reasonable cause, you file within 3 years and 75 days of the intended effective date, and everyone has reported income consistently with S status. Under Rev. Proc. 2013-30, shareholder statements are required. Do not wait.
What is an 83(b) election?
If you receive stock that vests over time, the election lets you pay tax on its value at the start (often close to zero for a new company) instead of as it vests. It must be filed within 30 days of the transfer and cannot be fixed later.
Does an LLC need Form 8832 to be taxed as a corporation?
An LLC that files Form 2553 for S status is treated as electing corporate classification. Form 8832 is for electing corporate or partnership classification without an S election. It can be effective up to 75 days before filing and up to 12 months after.
Is the EIN free?
Yes. Apply online with the IRS. Beware of websites that charge for an EIN. You can apply for only one EIN per responsible party per day.
Official sources
- IRS: Instructions for Form 2553 (S corporation election)
- IRS Rev. Proc. 2012-29 (section 83(b) election)
- IRS: Apply for an EIN online (free)
- IRS Publication 583: Starting a business and keeping records
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