409A Valuation Explained: What Every Startup Employee Needs to Know

When you join a startup and receive stock options, the strike price on your grant document is set by something called a 409A valuation — an independent appraisal of your company's common stock. Most employees glance at the number and move on. That's a mistake. The 409A affects how much you'll owe in taxes when you exercise, whether your early-exercise timing is optimal, and whether your employer even granted the options legally. This guide explains what the 409A is, why common stock is worth less than the last round price, and what questions to ask before you sign anything.

What is a 409A valuation?

A 409A valuation is an independent third-party appraisal of the fair market value (FMV) of a private company's common stock. The name comes from IRC § 409A, the tax code section that governs nonqualified deferred compensation. Stock options granted with a strike price below FMV are treated as discounted deferred compensation under § 409A — triggering severe tax penalties for the employee who holds them.¹

To avoid those penalties, companies commission a 409A appraisal before issuing option grants. The result is a formal report stating: "Based on the income, market, and asset approaches, common stock of Company X is worth $Y per share as of date Z." That FMV number sets the floor for option strike prices. Every ISO and NSO you receive must be struck at or above that number.

Why your strike price is lower than the last funding round price

The most confusing thing most startup employees encounter: the company just announced a Series B at $15 per share, but your options are struck at $4.50. That looks like an immediate 3× gain — but that's not how it works, and understanding why is essential to evaluating your equity correctly.

The $15 per share reflects the price of preferred stock. Investors buy preferred. Employees hold common stock (via options). Preferred stock is more valuable because it carries features that common stock doesn't have:

• Liquidation preference: in any acquisition or wind-down, preferred shareholders get their investment back first — often at 1× or 2× invested capital — before common stockholders receive anything.
• Anti-dilution protection: if the company raises a down round, preferred shareholders' effective ownership is protected through conversion adjustments; common holders bear the full dilution.
• Participation rights: some preferred shares "double-dip" — they take their liquidation preference and then participate in residual proceeds alongside common, leaving less for common.

The 409A appraisal accounts for all of this using an option pricing model that treats each share class like a tranche of call options on the company's total equity value. After applying a discount for the common stock's lower liquidation priority and a discount for lack of marketability (DLOM) — since private shares can't be sold freely — common stock is typically valued at 25–60% of the most recent preferred share price, depending on stage and capital structure complexity.

The 12-month expiration rule and material events

Under Treasury Regulation § 1.409A-1(b)(5)(iv)(B), a 409A valuation is presumed to reflect FMV for 12 months from the valuation date — provided no material event has occurred.² After 12 months, or immediately after a material event, the valuation is stale and the company must commission a new appraisal before issuing any more option grants.

Events that require a new 409A immediately:

• Closing a new priced funding round (any series)
• Closing a large SAFE or convertible note above a materiality threshold
• Signing a letter of intent for an acquisition
• A major revenue milestone, large contract win or loss, or IPO filing

Why this matters to you as an employee: If your company closed a Series C in March and it's now November, any option grant issued to you since March should have been priced using a new 409A commissioned after the Series C closed. If the company issued your grants in July using a valuation from before the Series C, those grants might be using a stale FMV. The IRS won't sue your employer — the tax penalty for discounted options falls on you, not the company.

The § 409A trap: discounted options and the 20% excise tax

If the IRS determines that your options were granted with a strike price below the true FMV at grant date, your options are treated as nonqualified deferred compensation under § 409A. The tax consequences hit the employee hard:¹

• The option's value (spread between strike price and FMV) is includable in your gross income in the year the option vests — not when you exercise
• An additional 20% excise tax applies on top of ordinary income tax and any state income tax
• An interest charge applies at the federal underpayment rate plus 1% on the deferred amount, going back to when the option first vested

This is a bill you cannot avoid by declining to exercise. If a Series A startup granted you options without a proper 409A, and the IRS later determines those options were under-priced, you owe ordinary income tax plus 20% extra on the spread value — calculated at each vest date — with no cash from actual shares to pay it. It's one of the worst tax traps in startup compensation.

ISO holders have an additional exposure: an ISO struck below FMV loses its ISO status entirely and becomes an NSO, subject to ordinary income tax at exercise rather than at vest — but also losing the preferential capital gains treatment that makes ISOs valuable in the first place.³

Early exercise timing: how the 409A shapes your 83(b) strategy

If your option agreement permits early exercise — most startup option agreements do — you can buy shares before they vest and file a Section 83(b) election within 30 days to lock in your tax basis at the current FMV. The 409A FMV is the number that determines what you owe at early exercise.

This creates a real timing opportunity:

• Exercise immediately after grant: Your strike price equals the 409A FMV — the spread is zero. You recognize zero ordinary income (or zero AMT spread for ISOs). The 83(b) election locks in the LTCG clock and QSBS clock at nearly zero cost.
• Exercise before the next funding round: If a new round is imminent, the next 409A will reflect a higher FMV. Exercising before that happens means the spread is calculated against the lower current FMV. Every dollar of FMV increase between now and when you exercise is a dollar of taxable spread you'll pay ordinary income tax on (or AMT, for ISOs).
• Exercise after a raise: The new 409A will typically show a higher FMV. Waiting means a larger income event at exercise — more AMT exposure for ISO holders, and more ordinary income exposure for NSO holders.

How to read your option grant in relation to the 409A

Your option grant agreement will contain language citing the exercise price as the FMV at grant date as determined by the Board of Directors in reliance on an independent appraisal. Look for this specifically. If the grant document does not reference an independent appraisal, ask why — a board-only valuation without a third-party appraiser does not qualify for the § 409A safe harbor.²

The 409A report itself is typically not distributed to employees. You can ask HR or legal for a copy, or at minimum ask to confirm that:

• The valuation was done by an independent third-party appraiser (not just the board)
• The valuation date is within the last 12 months
• No material event has occurred since the valuation date
• The strike price on your grant equals the per-share FMV from that report

Questions to ask before signing

Most HR onboarding materials skip these details entirely. Ask them specifically before you accept:

1. "What is the date of the most recent 409A valuation?" — anything over 12 months old is a red flag.
2. "Did a new priced round close after the last 409A?" — if yes, confirm a new appraisal was commissioned before your grant date.
3. "Were my options priced at the 409A FMV?" — get this confirmed in writing.
4. "What is the preferred share price from the most recent round?" — divide by your strike price to see the implied common-to-preferred ratio. If common is valued at 80%+ of preferred for a Series B company, that's unusual and worth questioning.
5. "Does the agreement allow early exercise, and what's the process?" — if yes, start the early-exercise decision analysis now, not in two years when the FMV is much higher.