The 83(b) election: the 30-day window, and what happens if you miss it

What the election actually does

Section 83 of the tax code governs property transferred in connection with services. The default rule is straightforward: you are taxed when the property is no longer subject to a substantial risk of forfeiture — in most cases, when it vests. The amount is the fair market value at vesting minus whatever you paid for it, taxed as ordinary compensation income.

That default is fine when the stock does not move. It is punishing when the stock appreciates. If you receive founder shares worth a fraction of a cent and they vest over four years while the company raises three rounds, you recognize ordinary income at each vesting date, at each new valuation. The tax follows the stock price up.

An 83(b) election flips the timing. You elect to be taxed at the moment of transfer, on the spread between the value then and what you paid. Everything after that is capital appreciation, not compensation. Your holding period for long-term capital gain treatment starts at the transfer date rather than at each vesting date.

For founder stock purchased at fair market value on day one, the spread is zero. The election costs nothing in current tax and moves the entire upside into capital gain territory. That is why the election is close to reflexive at formation — and why the 30-day window causes so much damage when it slips.

Who this applies to

The election is available where property is actually transferred to you subject to a risk of forfeiture. In practice that means two situations:

Restricted stock. Shares you own outright, subject to a company repurchase right or forfeiture condition tied to service or milestones. Founder stock, restricted stock purchase agreements, and restricted stock awards at private companies.

Early-exercised options. Plans that let you exercise unvested options and receive shares immediately, with the company retaining the right to buy back unvested shares if you leave. The shares are property. The repurchase right is the risk of forfeiture. The election is on the table.

For early-exercised incentive stock options, the election operates for alternative minimum tax purposes — it fixes the AMT preference item at the exercise date instead of letting it grow at each vesting date. The regular-tax analysis for ISOs runs on its own track.

Why standard RSUs are different

This is the most common misunderstanding we encounter, and it is worth being precise about.

A restricted stock unit is not stock. It is an unfunded contractual promise to deliver shares later, if conditions are met. No property changes hands at grant. Section 83 applies to transfers of property — so there is nothing to elect on.

You cannot file an 83(b) election on standard RSUs at a public company. You cannot file one on double-trigger RSUs at a private company either. Executives arriving from a startup background sometimes assume the election is a universally available lever. It is not. With RSUs, the taxable event is settlement, the value is the share price on that date, it runs through payroll withholding, and the planning question is about sell-to-cover decisions and withholding rates — not elections.

The terminology does not help. "Restricted stock" and "restricted stock units" are different instruments with different tax mechanics. Read the grant agreement, not the shorthand in the offer letter.

The 30-day window, and how it is counted

Thirty calendar days from the date of transfer. Not thirty business days. Not thirty days from when you signed the paperwork, or when the board consented, or when the certificate arrived.

The count begins the day after the transfer date and includes weekends and holidays. If day 30 falls on a Saturday, Sunday, or legal holiday, the election is generally treated as timely if it goes out on the next business day. That is the only softening in the rule.

The transfer date is a question of fact, and it is not always obvious. Purchase agreements, board consents, and payment dates do not always align. Determining the correct date is legal work, and it is worth doing on day one rather than day 28.

Filing mechanics

The IRS released Form 15620 for section 83(b) elections, and added an electronic filing option in 2025. A properly drafted statement remains acceptable, but the standardized form removes a category of drafting error.

The substance required is consistent: your name, address, and taxpayer identification number; a description of the property; the date of transfer and the tax year involved; the nature of the restrictions; the fair market value at transfer determined without regard to lapse restrictions; the amount paid; and confirmation that copies were furnished as required.

Two practical points. First, provide a copy to the company — it affects their withholding and reporting. Second, keep proof. Certified mail with return receipt, or the electronic filing confirmation. The IRS does not send an acknowledgment, and the burden of proving timely filing sits with you. We have seen an entire tax position turn on a green card in a folder.

Once filed, the election cannot be revoked except with the consent of the Commissioner, and consent is granted narrowly — a mistake of fact about the underlying transaction, raised within 60 days of discovery. A stock price that went the wrong way is not a mistake of fact.

When it helps, and when it backfires

The election helps when the spread at transfer is small and the expected appreciation is large. Founder stock at formation is the clean case: zero spread, zero current tax, maximum conversion of future gain to capital treatment.

It backfires in the other direction. You pay real tax, in real cash, on stock you cannot sell. If the company fails, that tax is gone. There is no refund and no deduction for the income you recognized. If you forfeit the shares, you may claim a capital loss limited to what you actually paid — not the compensation income you reported. The economics are asymmetric, and they are worst when the spread at transfer is already large.

The judgment call sits between those poles: a meaningful spread, an illiquid position, and a company whose outcome is genuinely uncertain. That is a sizing and liquidity question, not a tax-form question.

What happens if you miss the window

Nothing good, and nothing that resembles a fix.

You revert to the default rule. Each vesting tranche is an ordinary income event at that date's fair market value. At a company that is appreciating, that produces a rising tax bill on shares you cannot sell to pay it. Your capital gains holding period starts at each vesting date. And the company generally has to run the income through payroll, with withholding and employment taxes attached.

There is no late-filing procedure. Counsel sometimes explores structural responses — confirming whether a valid transfer actually occurred, exchanging unvested shares for a new grant that opens a fresh window, or adjusting repurchase terms. These are fact-specific, they are securities and corporate law questions before they are tax questions, and they are not always available. They are a conversation with the company's counsel, started immediately.

The QSBS connection

Qualified small business stock under section 1202 can exclude a substantial portion of gain from federal tax if the holding period is satisfied. The holding period is the point here.

With a timely 83(b) election, the QSBS clock starts at the transfer date for the entire block. Without one, each vesting tranche generally starts its own clock at its own vesting date. Four-year vesting turns one holding period into four, and the last one finishes years after the first.

That distinction can decide whether an exit qualifies. An acquisition that lands in year five is fully seasoned under one scenario and partially seasoned under the other. The 2025 legislation revised the QSBS regime — including tiered exclusions and higher caps for stock acquired after the effective date — so the specific thresholds require verification against the rules applicable to your acquisition date.

What to gather, and who to coordinate with

Before the clock runs, assemble: the stock purchase or grant agreement, the board consent and its date, evidence of the purchase price paid, the most recent 409A valuation or other support for fair market value, and the vesting and repurchase terms.

Coordinate with company counsel on the transfer date and the form of election, with your CPA on the current-year tax and estimated payments, and with your advisor on whether paying tax now on an illiquid position fits the rest of your balance sheet. These are three different questions. They are frequently answered by one person who was only asked one of them.

This article is educational and is not tax, legal, or investment advice. Individual circumstances differ, and the rules change.