4A
409A Pro
Home/Resources/409A Valuation Audit Defense

409A Valuation Audit Defense

A 409A audit defense involves the appraiser responding to auditor challenges on valuation methodology, comparable company selection, DLOM assumptions, and OPM parameters. Choosing an appraiser who provides active audit support — not just a report — is critical for companies with Big 4 auditors.

Published April 20, 2026
3 min read

Key Takeaways

  • Big 4 auditors test your 409A as part of their stock-based compensation audit procedures
  • Auditors focus on comparable company selection, growth assumptions, DLOM, and OPM parameters
  • Your appraiser should actively respond to auditor management letters and comment letters
  • A well-documented 409A reduces audit time and protects against restatement risk
  • Restatement of prior-period SBC expense due to a failed 409A is extremely costly
  • Appraiser selection matters: choose one with experience defending to your specific audit firm

How Big 4 Auditors Review 409A Valuations

When your company undergoes a financial statement audit, your external auditors are required under PCAOB and GAAP standards to test the fair value of stock options granted during the period. This involves a detailed review of your 409A valuation report and, often, direct communication with your appraiser.

The Audit Review Process

A typical Big 4 audit review of your 409A proceeds as follows:

  1. Initial documentation request: Auditors request your 409A report, all supporting schedules, cap table as of the valuation date, and the appraiser's credentials
  2. Reasonableness testing: Auditors perform their own estimate of FMV using the same general approach (often a simplified model) to assess whether your 409A conclusion is within a reasonable range
  3. Comparable company challenge: Auditors often challenge the selection of comparable public companies, asking why specific companies were included or excluded
  4. OPM/PWERM assumption review: Auditors test key assumptions — expected term, volatility, DLOM — against market data and industry benchmarks
  5. Management letter / AJE: If auditors conclude the 409A FMV is materially different from their estimate, they may propose an audit adjustment (AJE) to restate option grant fair values

Common Audit Challenges and Responses

  • "Your comparable companies are too high-growth": Auditors may argue that selecting high-multiple SaaS comps inflates the enterprise value. Response: Document the selection criteria and why excluded companies are less comparable.
  • "Your DLOM is too high": If auditors believe the company is closer to a liquidity event than DLOM implies, they will push for a lower discount. Response: Provide board minutes, investor communications, and timeline analysis supporting the assumed liquidity horizon.
  • "Your revenue projections are too optimistic": DCF-heavy valuations are sensitive to growth assumptions. Response: Tie projections to historical actuals and provide conservative case scenarios.

Choosing an Audit-Ready Appraiser

Not all 409A providers are equal when it comes to audit support. When evaluating providers, ask:

  • Have they previously defended valuations to your specific audit firm?
  • Do they provide unlimited audit support, or charge per hour?
  • What is their track record — have any of their valuations required material restatement?
  • Are the lead analysts CVAs or ABVs with verifiable credentials?

Need a formal 409A valuation?

IRS-compliant, auditor-defensible reports in 5–14 business days. Starting at $1,500.

Get Your Quote