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Material Events That Trigger a New 409A Valuation: Complete List for 2025

A material event is any development that significantly changes a startup's fair market value, invalidating the current 409A valuation regardless of whether it is still within its 12-month validity window. The most common material events are closing a new funding round, receiving an acquisition offer, and material changes in financial performance — but many founders are unaware of the less obvious triggers.

Published April 22, 2026
3 min read

Key Takeaways

  • A material event invalidates your 409A immediately — even if it was just completed last week
  • Closing any priced equity round (Seed, Series A, B, C) is always a material event
  • Signing a term sheet does not trigger a new 409A — but closing the round does
  • A signed letter of intent (LOI) for acquisition is a material event even if the deal may not close
  • A dramatic revenue decline (50%+) or loss of a major customer can constitute a material event
  • When in doubt, consult your 409A appraiser — the cost of an unneeded refresh is far less than an IRS penalty

Why Material Events Invalidate Your 409A

A 409A valuation is a snapshot of your company's fair market value on a specific date. The IRS provides a 12-month safe harbor — an assumption that the FMV has not changed materially within that window. But certain events so fundamentally alter the company's value that this assumption breaks down. These are material events.

When a material event occurs, the safe harbor is immediately voided. Any option grants made after the material event but before a new 409A is completed are non-compliant — they are treated as having been granted without a valid FMV determination, exposing employees to §409A penalties.

Complete List of Material Events

Financing Events (Always Trigger New 409A)

  • Closing a priced equity round: Any SAFE conversion, seed round, Series A through Series N — the moment a round closes, the prior 409A is invalidated. This is the most common material event.
  • Closing a convertible note: While individual note closings may not always trigger a new 409A if the terms are similar to existing notes, a material bridge round often does.
  • Completing an IPO: The company is no longer private — §409A options must be granted at the market price going forward.

M&A and Transaction Events

  • Signed letter of intent (LOI) for acquisition: A signed LOI — even one that hasn't closed — creates a known potential exit at a specific price. This is considered a material event because it represents concrete evidence of value that was not present at the last 409A date.
  • Executed term sheet for acquisition: Even stronger evidence of value.
  • Completed secondary transaction at significantly different price: If the company or shareholders complete a secondary at a price materially above or below the current 409A FMV, this may constitute a material event.

Company Performance Events

  • Revenue milestone: Reaching a major revenue threshold (e.g., crossing $1M, $5M, $10M ARR) may constitute a material event if it was not anticipated in the last valuation
  • Material revenue decline: A 40–50%+ decline in revenue — due to customer churn, market shift, or product failure — is a material negative event
  • Loss of a major customer: If a single customer represents 30%+ of revenue and churns, this is a material event
  • Signing a transformative customer contract: Landing a marquee enterprise contract that materially changes revenue projections
  • FDA approval or rejection (HealthTech/BioTech): Regulatory approval or rejection events are always material

Strategic and Structural Events

  • Major acquisition completed by the company: If you acquire another business, your cap table, financials, and enterprise value all change materially
  • Significant change in business model: Pivoting from B2C to B2B, adding a hardware component to a software product, or exiting a major business line
  • IPO filing (S-1 submission): Filing the S-1 creates a known IPO price range, making the existing 409A effectively obsolete

The Urgency Timeline

Material EventHow Quickly to ActRisk of Delay
Equity round closesEngage appraiser within 1–5 days; complete within 30 daysHigh — cannot grant options until complete
LOI signed for acquisitionPause grants immediately; consult appraiser within 1 weekVery high — LOI price anchors FMV
Major revenue event (positive)Consult appraiser within 2 weeks to assess whether 409A is requiredMedium — depends on materiality
Major revenue event (negative)Consult appraiser within 2 weeksMedium — lower FMV may benefit new grants
S-1 filedImmediately — transition to public market pricingCritical — SEC will scrutinise

What Is Not a Material Event

To avoid unnecessary costs, it is also important to know what does not typically constitute a material event:

  • Signing a term sheet for a funding round (only closing triggers it)
  • Adding a new team member or executive (unless they bring a transformative customer or contract)
  • Normal business growth within the range contemplated by the last valuation
  • Reaching 12 months (this triggers expiry, not a material event — though the outcome is the same: you need a new 409A)
  • Launching a new product feature (unless it represents a fundamental business model change)

Educational Content — Not Tax or Legal Advice

The information on this page is provided for general educational purposes only. It does not constitute tax advice, legal advice, or a formal valuation opinion. Every company's situation is different — consult a qualified tax adviser, attorney, or certified valuation analyst before making decisions based on this content.

State law may vary. Individual US states may impose additional income tax, excise tax, or reporting obligations on nonqualified deferred compensation and stock options. California, for example, imposes an additional penalty tax of up to 20% on top of federal penalties. Always review applicable state rules with local counsel.

Primary source: IRC Section 409A and the final Treasury Regulations under T.D. 9321 (IRS Internal Revenue Bulletin 2007-19). For the most current IRS guidance, penalties, and safe harbor requirements, refer to the IRS IRC 409A Overview page directly.

Content last reviewed: August 2026. Tax law changes frequently — readers are encouraged to verify current rules with the IRS or a qualified professional before relying on this content.

409A Valuation Pro is not affiliated with, endorsed by, or sponsored by the Internal Revenue Service or any US government agency. IRS, Internal Revenue Service, and related names are trademarks of the US Department of the Treasury.

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