Case study: the missed 83(b) that cost six figures

An early hire skipped the form, then vested into a unicorn valuation. The tax bill arrived years before any chance to sell.

Restricted stock · Case studies

How much can one unsent letter cost? For an early engineer I will call Dana, it ran into six figures of tax on stock she could not sell. Dana is a composite, the details changed to protect the real people, but the shape of this one is common enough that I have seen it more than once.

The setup

Dana joined a young startup as employee number nine. She got a restricted stock award, real shares that vested over four years, granted when the company was worth almost nothing. Her shares were priced at a fraction of a cent. Filing an 83(b) election in those first 30 days would have cost her a trivial tax, maybe a dinner’s worth.

Nobody walked her through it. The grant paperwork mentioned the election in a sentence she did not understand, the 30 days passed, and she moved on. The form never got filed.

What happened next

The company took off. Three funding rounds in four years pushed the share price up hard. Because Dana never filed, the tax code taxed her shares as they vested, at each year’s valuation, as ordinary income.

First vest, easy to ignore

Her first slice vested at a low price. The extra income was small, so the problem stayed invisible.

The valuation reset upward

Each new round raised the share price. Every vest after that was taxed at the new, higher value.

The bill went vertical

By the later vests, the company carried a unicorn valuation. Dana was reporting large ordinary income each year on shares that were still completely private.

Caution

The shares were worth a lot on paper and worth nothing in her bank account. She could not sell private stock to pay the tax, so the bill came out of salary and savings, year after year, exactly the trap that catches people who miss the deadline by accident.

Where the money went

Had Dana filed, she would have paid a tiny tax at grant and turned all that later growth into a capital gain, taxed at the lower long-term rate, only when she actually sold. For 2026 that long-term rate is 0%, 15%, or 20% depending on income 2026, with the 3.8% net investment income tax possible on top 2026. Instead she paid the higher ordinary rate, which for 2026 tops out at 37% 2026, on a schedule the vesting calendar dictated, on value she could not yet reach.

Dana’s actual rate on each vest came down to her own 2026 marginal bracket, not just the top rate above.

Confirm the QSBS numbers with counsel

The QSBS rules changed in 2025, and the exact exclusion percentage, per-issuer cap, gross-assets ceiling, and holding-period tiers depend on when your stock was issued and your specific facts. Treat the figures here as directional, and confirm the current numbers with a tax professional before you rely on them.

The lesson

The election is not advanced tax planning. It is a one-page letter with a hard 30-day clock, and on near-zero stock the downside of filing is almost nothing. Dana did not lose six figures to a complicated mistake. She lost it to a form she did not know to send.

If you are getting founder or early-employee stock that vests, treat the 83(b) decision as the first thing you do, not the last. Read how to file the week your shares are granted, and if your stake could ever get large, get a fast read before the window closes.

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