An 83(b) election is roughly twenty minutes of paperwork attached to a 30-day fuse. Filed on time, it can convert years of future appreciation from ordinary income into capital gain and start your QSBS clock at grant. Missed, it becomes one of the most expensive administrative errors in startup life, with no way to fix the filing after day 30.
The good news is that filing has never been easier. The IRS introduced a standardized form, Form 15620, in late 2024, and since 2025 you can submit it electronically through an IRS online account and walk away with a timestamped confirmation instead of a certified mail receipt. This guide covers the decision, the deadline, the filing paths, the form itself, and the records to keep afterward. If you are worried you already missed the window, go straight to our companion piece on what to do about a missed 83(b) deadline before you panic.
What an 83(b) Election Does
Section 83 of the Internal Revenue Code sets the default rule for stock you receive in connection with services while it is still subject to vesting: you are taxed as it vests, recognizing ordinary income at each vesting date equal to the fair market value of the shares that just vested minus what you paid for them. If the company grows while you vest, that spread grows too, and you owe tax on paper wealth at ordinary income rates, tranche by tranche.
The 83(b) election flips the timing. You elect to be taxed once, at the moment the stock is transferred to you, on the spread between fair market value and your purchase price at that moment. For a founder who buys stock at fair market value on day one, that spread is zero, so the election typically costs nothing to make. From then on, vesting is a non-event for tax purposes: future appreciation is capital gain, and both your long-term holding period and your Section 1202 QSBS clock start at grant rather than at each vesting date.
One property of the election matters before you file: it cannot be revoked without IRS consent, which is granted only in narrow circumstances. File deliberately, not reflexively.
Who Should File, and Who Should Not
The election only exists for property actually transferred to you subject to a substantial risk of forfeiture. In startup terms:
Founders with reverse-vested stock should file. If you purchased founder shares subject to a repurchase right on unvested shares when you leave, you hold restricted stock and the 30-day clock is running from your purchase date.
Restricted stock award recipients should usually file. If the company granted you actual shares subject to vesting, the same analysis applies, though the math deserves more attention when RSAs are granted at low or no cost while the stock has real value.
Early exercisers should file at exercise. If your option plan permits early exercise and you exercise before vesting, you receive unvested shares, and a fresh 30-day window opens on the exercise date. File the election with the exercise paperwork, ideally the same day.
Standard option holders should not file, because they cannot. An unexercised option is not a transfer of property, so there is nothing to elect on and no deadline running. The 83(b) decision for a normal option grant arrives only if and when you early exercise.
Fully vested shares need no election. If your shares carried no forfeiture conditions at issuance, the default rule already taxed you at transfer.
RSUs are not eligible. A restricted stock unit is an unfunded promise to deliver shares later, not a present transfer of property, so no election is possible.
For a broader walkthrough of eligibility and the filing package, our 83(b) election guide covers the same ground in checklist form.
The Decision in Brief: File When the Spread Is Small
The election is close to a free option when fair market value at transfer equals what you paid, which is the standard founder situation at incorporation. You recognize zero income now, and you cap the ordinary income component of your equity at zero forever.
A deliberately simple, entirely hypothetical example: a founder purchases 1,000,000 shares at $0.001 per share, paying $1,000 total, with four-year vesting.
With a timely election: income at transfer is fair market value minus price paid, which is zero. Nothing happens at any vesting date. Five years later the company is acquired and the shares sell for $3.00 each, producing $3,000,000 of proceeds. The entire gain is long-term capital gain, and because the holding period and QSBS clock started at grant, some or all of it may qualify for the Section 1202 exclusion.
Without the election: each vesting tranche is taxed at its then-current value. If a seed round pushes the common stock's fair market value to $0.25 by year two, the roughly 250,000 shares vesting that year generate about $62,000 of ordinary income, with nothing sold and no cash to pay the tax. If a Series A pushes value to $1.00 by year four, that year's vesting alone generates around $250,000 of ordinary income. The total bill is far larger, arrives years earlier, and lands on illiquid stock.
When is filing a real decision rather than a reflex? When there is a meaningful spread at transfer, because the election makes that spread taxable immediately. And filing has one genuine downside even at zero spread: if you later forfeit the shares by leaving early, you get no deduction for income recognized under the election, and your loss is limited to what you actually paid. For a low-cost founder purchase that risk is small in dollars. For a large early exercise at a meaningful strike price, it deserves modeling before you commit cash and tax to shares you might forfeit.
Step 1: Compute Your Deadline Correctly
The election must be filed no later than 30 days after the date the property is transferred. Get three things right:
Start from the transfer date. That is the date the shares were actually issued to you: typically the date on your restricted stock purchase agreement, or the date the board approved the issuance and you paid, whichever your documents establish. It is not the term sheet date, not the vesting commencement date, and not the date you received the paperwork. For an early exercise, it is the exercise date.
Count 30 calendar days, not business days. Count from the day after the transfer date. Day 30 is the deadline.
Apply the weekend and holiday roll. Under Section 7503, if day 30 falls on a Saturday, Sunday, or federal legal holiday, the deadline moves to the next business day. The Form 15620 instructions state this rule explicitly, and it is the only flexibility the deadline has. There are no extensions, no reasonable-cause relief, and no Section 9100 relief, because the 30-day requirement is written into the statute itself.
The practical advice is to make the count irrelevant: file the same day the shares are issued. Our glossary entry on the Section 83(b) deadline has the counting rules in condensed form.
Step 2: Choose Your Filing Path
There are three valid ways to file, and you should use exactly one of them.
Path A: E-file Form 15620 through an IRS online account. Since 2025 the IRS accepts 83(b) elections electronically. You sign in or create an account through ID.me, the IRS identity verification service, complete Form 15620 online, and submit. You receive an online confirmation of the submission, which is your proof of timely filing. This is the cleanest path for most filers: a timestamp beats a postmark. Two caveats. Electronic filing requires Form 15620; a custom letter cannot be e-filed. And practitioners have reported that the online tool's numeric fields may not accommodate very large share counts or per-share prices carried to many decimal places, the exact profile of many founder purchases at $0.0001 per share. If your numbers do not fit cleanly, file on paper rather than distorting them.
Path B: Mail Form 15620. Download the form, complete and sign it, and mail it to the IRS office where you file your federal income tax return, which is the address in your Form 1040 instructions for your state and what the Form 15620 instructions specify. Use certified mail with return receipt, for reasons covered in Step 4.
Path C: Mail a traditional letter election. Form 15620 is voluntary. A written statement containing the elements required by Treasury Regulation 1.83-2, essentially the same facts the form collects, remains valid when signed and mailed to the same address. Law firms used this format for decades and many still do, but if you are filing for yourself, the standardized form is harder to get wrong.
Whichever path you choose, do not file through two channels. The IRS asks e-filers to confirm the form has not been separately mailed, and duplicate submissions invite processing confusion.
Step 3: Complete the Form, Field by Field
Form 15620 collects nine boxes of information plus a signature. Qualitatively, here is what goes where:
Box 1: your identity. Legal name, taxpayer identification number, and mailing address. For most filers the TIN is a Social Security number; see the special cases below if you do not have one.
Box 2: the property. What was transferred and how much of it, in the style of 1,000,000 shares of common stock of Acme, Inc. Be specific about class and quantity.
Box 3: the transfer date. The date the property was transferred to you. This starts the 30-day clock, so it must match your issuance documents exactly.
Box 4: the taxable year. The tax year that includes the transfer date, which for nearly all individuals is the calendar year of the grant.
Box 5: the restrictions. A plain description of why the shares are substantially nonvested: for example, that they are forfeited or repurchased at cost if your service ends before vesting completes. Pull the language from your stock restriction agreement rather than improvising.
Box 6: fair market value. Per-share fair market value at transfer, quantity, and total. Value is determined without regard to restrictions that will lapse, meaning you use the unrestricted value. A current 409A valuation is the usual anchor.
Box 7: amount paid. Per-share price paid, quantity, and total. For an RSA granted at no cost, this is zero.
Box 8: the income. Box 6 total minus Box 7 total. For the standard founder purchase at fair market value this is zero, and zero is a perfectly valid answer. That zero is the whole point of filing early.
Box 9: the company. Name, TIN, and address of the company you provide services to. The form marks this box optional, but completing it is good hygiene.
Signature. You sign under penalties of perjury, and the signature block includes your agreement to provide copies to the company and to the transferee if the shares are held by someone other than you. An unsigned election is not an election.
Step 4: File It, and Keep the Proof
If you e-file, the confirmation is generated at submission. Save it as a PDF, screenshot it, and store both alongside a copy of the completed form. That timestamp is your permanent evidence of timely filing.
If you mail, the postmark is everything. Under Section 7502, the mailbox rule, a document postmarked within the deadline is treated as filed on the postmark date even if the IRS receives it later. Mail by certified mail with return receipt requested, and before the envelope leaves your hands, scan the signed election and the certified mail receipt with its postmark, then keep the return receipt card when it comes back. The IRS does not send acknowledgments of paper 83(b) filings, so the proof you create at mailing is the only proof you will ever have.
Step 5: Give a Copy to the Company
You are required to provide a copy of the election to the company you perform services for, and to the transferee of the shares if that is a different person, for example a trust holding your stock. Send it to whoever runs your equity records and keep evidence that you sent it. The company needs it for its own payroll and reporting positions, and every future financing will ask whether elections were filed for founder stock.
Step 6: Keep the Records Forever
Since 2016 you no longer attach a copy of the election to your federal income tax return; the IRS removed that requirement. Do not mistake that for the records not mattering. Your election and proof of timely filing will be requested at every priced round, in acquisition diligence, and by whoever prepares your return in the year you sell, and if you claim the QSBS exclusion at exit, the election is part of the paper trail supporting your holding period. Keep digital and physical copies in your permanent records, and give your counsel a set. Forever is not an exaggeration here.
Special Cases
Early exercised options. The mechanics are identical, but the clock starts at exercise, not at the original option grant. Treat the election as part of the exercise package: same-day signature and filing, with the exercise date in Box 3 and your strike price in Box 7. If the 409A value has risen since grant, Box 8 will be positive and you will owe tax on the spread, a reason to run the math before exercising, not to skip the election after you have.
Community property states and spousal consent. In community property states, a spouse may have a property interest in shares acquired during the marriage, and many practitioners recommend the spouse sign a consent to the election. The IRS form has no spouse line and practice varies, so if this applies to you, ask your counsel how to paper it rather than guessing.
Foreign founders without an SSN or ITIN. The form asks for a taxpayer identification number, and the e-filing route runs through ID.me identity verification, both obstacles for a founder who has neither an SSN nor an ITIN yet. The common approach is to file on paper within the 30 days, noting that an ITIN application via Form W-7 is in process, but the details depend on your status and deserve professional guidance. The deadline does not wait for your paperwork, so do not delay the election while an application is pending. Our guide to US startup taxes for foreign founders covers the wider identification and filing picture.
The Mistakes That Invalidate Filings
Most failed elections die from one of a short list of errors:
- Filing late. Day 31 is too late, full stop. No extension exists and courts have enforced the deadline against sympathetic facts.
- Counting from the wrong date. Using the vesting start date, the board meeting date, or the option grant date instead of the actual transfer or exercise date can silently move your real deadline.
- Not signing. An unsigned form or letter is not a valid election.
- Leaving out required elements in a letter election. A homemade letter missing the transfer date, the value figures, or the restriction description invites a validity fight years later. If in doubt, use Form 15620.
- No proof of filing. Regular first-class mail with no certified receipt leaves you unable to prove the postmark. If the IRS has no record and you have no receipt, you have no election.
- Assuming someone else filed. The most common failure is an ownership gap: the founder assumed the law firm filed, the firm assumed the founder did. Confirm in writing who owns the filing and demand the proof when it is done.
- Filing for ineligible grants. An election filed for RSUs or unexercised options is a nullity; it neither helps nor substitutes for the election you may need later at early exercise.
If You Think You Missed the Window
First, verify. Recount from the correct transfer date, apply the weekend roll, check for a qualifying postmark under the mailbox rule, and confirm whether counsel or your cap table platform filed on your behalf. A meaningful share of feared misses turn out to be timely filings with misplaced proof. If the miss is real, the election itself cannot be repaired, but structural paths exist, and in one situation doing nothing is genuinely fine. Our guide to handling a missed 83(b) deadline walks through the verification steps, the cost math, and the remediation options in detail.
Filed correctly and on time, the 83(b) election is the rare piece of tax paperwork with an enormous payoff and a trivial cost. At StartupCFO we treat it as part of stock issuance itself, not a follow-up task. If your equity also involves salary decisions, our guide on how to pay yourself as a startup founder covers how the pieces fit together.
This article is for general informational purposes only and is not tax, legal, or accounting advice. Whether and how to make an 83(b) election depends on your specific facts, and the filing, valuation, and spousal consent questions discussed here should be reviewed with a qualified tax adviser before you sign anything.
