Founder guide · checked 13 October 2026

83(b) election deadline calculator

If you got founder shares that vest over time, you have 30 days from the day the shares were issued to you to mail an 83(b) election to the IRS. There are no extensions and no fixes if you miss it.

Date the shares were issued or transferred to you

Who needs an 83(b) election

Anyone who receives restricted stock: shares that can be taken back if you leave before they vest. That's the normal setup for co-founders of a Delaware C-corp, and accelerators and investors usually expect it. Without the election, the IRS treats each vesting date as income equal to the shares' value then, which can be a large tax bill on paper gains. With it, you're taxed once on the value at grant, usually close to zero for a new company.

It doesn't apply to stock options (until exercised), to shares that are fully vested on day one, or to LLC units in most cases. Ask your company's lawyer if unsure.

Founders outside the US

Non-US founders of US startups are often told to file one anyway, because if they ever move to the US or the shares become taxable there, the election protects them, and it costs only postage. Whether it matters for you depends on where you pay tax; a cross-border tax adviser can confirm.

How to file

1. Fill in IRS Form 15620 (Section 83(b) Election), or a letter with the same details: your name, address and tax ID (SSN or ITIN; write "applied for" or leave it blank if you have none), the shares, the grant date, the vesting restrictions, the value and what you paid.
2. Sign it and make copies.
3. Mail it to the IRS address in the Form 15620 instructions by certified mail with return receipt, postmarked by the deadline. From outside the US, use a courier service the IRS accepts as a "private delivery service" and keep the receipt.
4. Give a copy to your company. Keep your copy and proof of mailing forever: investors and acquirers ask for it.

You no longer have to attach a copy to your tax return.

If you miss it

The IRS doesn't accept late 83(b) elections. Workarounds exist (for example, the company cancelling and re-issuing the shares with a new grant date), but they need a lawyer and may not work. Calendar the deadline the day you sign.

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Sources: Internal Revenue Code §83(b) and Treasury Reg. §1.83-2 (30-day rule, no attachment to return since 2016); §7503 (weekend and holiday rule); §7502 (timely mailing); IRS Form 15620.