The 83(b) Election Explained: Why You Have 30 Days to Save Yourself From a Tax Disaster

If you're a US founder with vesting equity — which is essentially every founder who's raised institutional capital — you have 30 days from the date you receive your shares to file an 83(b) election with the IRS. Miss the deadline, and you face a tax bill that could eventually run into the millions.

This article explains what the 83(b) is, why it matters, and exactly how to file.

The short version

When you have shares subject to vesting, the IRS treats your equity as taxable income as it vests, at the share price at the time it vests. If your company is worth a lot more in year 4 than in year 0, you'll owe taxes on the appreciation as if it were salary.

The 83(b) election lets you tell the IRS: "I want to be taxed on the value of these shares now, when they're worth almost nothing, instead of as they vest." Most founders' shares are worth essentially zero at issuance, so the 83(b) means paying tax on a very small amount once, and never again on the appreciation.

You have 30 days from the grant date to file. Miss it and you cannot retroactively elect.

A worked example

Suppose you found a company. You're issued 4 million shares at $0.0001 per share at incorporation, vesting over 4 years. Total value at issuance: $400.

With an 83(b) filed: You owe tax on $400 of "income" today. At a high tax rate, maybe $150. You pay it. Done.

Without an 83(b): Each year, as 1m shares vest, you owe tax on the current value of those shares as ordinary income. If your company is worth $50m by year 2, your 1m shares are worth $500k. You owe tax on $500k as if it were salary — even though you haven't sold anything. By year 4, if the company is worth $500m, you owe tax on $5m of "phantom" income.

The 83(b) is the difference between paying $150 once and paying perhaps $2m+ over four years on income you haven't actually received in cash.

Who needs to file

Anyone with shares subject to vesting:

• Founders. Who almost always have founder shares with reverse-vesting at the first institutional round.
• Early employees. With restricted stock awards (RSAs), not options.
• Co-founders joining later. Same rule applies.

If you only have options (ISOs or NSOs), the 83(b) doesn't apply unless you early-exercise them. Standard option grants don't trigger 83(b) elections.

When 83(b) becomes relevant

Two common scenarios:

1. At incorporation. Founders typically issue themselves shares at incorporation. If those shares are immediately fully vested, no 83(b) needed. If they're subject to a vesting schedule (which most early-stage corporate counsel will recommend, especially before raising), 83(b) needed within 30 days of the grant.

2. At first institutional financing. Investors often require founders to "re-vest" their shares at the time of the priced round. Even if your shares were previously fully vested, the re-vesting agreement creates a new vesting schedule — which means a new 83(b) opportunity. File within 30 days of the financing.

How to file

The mechanics are straightforward:

1. Use the standard 83(b) form. Most lawyers will provide it; the IRS template is publicly available.
2. Fill it in. Your name, address, SSN, the company name, the number of shares, the value at grant, the vesting schedule.
3. Sign it.
4. Make three copies. - One to mail to the IRS (use the address for your state). - One for your own files. - One for the company's records.
5. Mail to the IRS within 30 days of the grant date — by certified mail with return receipt requested. This step is critical.
6. Keep the proof of mailing forever. Yes, forever. The IRS sometimes loses filings; your proof is your defence.
7. Optionally include the 83(b) with your next year's tax return. The IRS no longer formally requires this since 2016, but some lawyers recommend it for belt-and-braces.

That's it. The whole process takes maybe 30 minutes plus a trip to the post office.

What "30 days" actually means

The 30-day window is from the date of grant — typically the date the shares are issued and you take ownership. Not from the date the round closes, not from the date you started the company.

If your grant date is January 15, your 83(b) must be postmarked no later than February 14. Day 31 is too late.

The IRS does not extend the deadline. There is no retroactive 83(b). Miss the deadline, and you're stuck with the worse tax treatment for the life of those shares.

The most common 83(b) mistake

By far the most common mistake: forgetting to file.

This happens because:

• The company doesn't remind you (your lawyer should, but doesn't always).
• You're focused on closing the round, not paperwork.
• 83(b) doesn't appear in any closing checklist with a hard deadline.
• The 30 days passes without notice.

The fix: the moment you sign anything that creates vesting, set a reminder for 25 days later: "File 83(b)." Treat it as the same priority as wiring the closing payment.

What if you miss the deadline?

If you miss the 30-day window, you cannot file 83(b) for those shares. Your options:

• Continue with default tax treatment (taxed as shares vest, on appreciated value).
• Re-issue new shares with a new grant date — sometimes possible if pre-financing, requires careful legal coordination.

Neither is ideal. Don't miss the deadline.

When 83(b) is not the right call

Almost always file. The case for not filing is rare:

• You believe the shares will be worth less in the future than today (almost no founder believes this; rare except for distressed situations).
• The shares are already worth a lot, so paying tax now is significant.

For most founders, the upside is huge and the cost is small. File.

What about non-US founders?

The 83(b) is a US tax mechanism. Non-US founders incorporated outside the US don't file 83(b) elections — but should research the equivalent in their jurisdiction. UK has different rules (typically more favourable by default for founder shares); EU countries vary.

If you're a non-US founder who has flipped to Delaware and become a US tax resident, the 83(b) does apply to you.

A reminder you cannot afford to skip

The 83(b) is the smallest piece of paperwork in your fundraise. It's also one of the most consequential. A 30-minute task can be the difference between paying $150 in taxes and paying millions over the life of the company.

When you sign your founder vesting documents, mark "File 83(b)" on the calendar 25 days out. Send it. Get the proof of mailing. File it away.

The investors and lawyers helping you with the round will assume you filed. They will not chase you. The responsibility is yours.