A 409A valuation is an independent appraisal of a private company’s common stock fair market value, done to set option strike prices at or above that value and satisfy Internal Revenue Code Section 409A, which governs nonqualified deferred compensation.

Founders care because a defensible 409A valuation is what lets you grant stock options without triggering Section 409A penalties on your own team, which is why most startups line one up soon after they get incorporated. Skip it or lowball it and the IRS can tax option holders early and add a steep surcharge.

Why a 409A valuation matters

Section 409A taxes deferred compensation that fails its rules. A stock option counts as deferred compensation unless it is exempt. The main exemption requires a strike price no lower than the stock’s fair market value on the grant date. A 409A valuation sets that fair market value.

The penalty for getting it wrong is severe. Under Section 409A(a)(1), the compensation becomes taxable when it vests rather than when it pays out, and Section 409A(a)(1)(B) adds a 20% additional tax on top of regular income tax, plus an interest charge. That falls on the employee, not just the company.

The safe harbor and the 409A appraisal

The regulations give startups a way to shift the risk. Treasury Regulation Section 1.409A-1(b)(5)(iv)(B) creates a presumption that a valuation is reasonable when it comes from a qualified independent appraisal that is no more than 12 months old and the facts have not materially changed. The IRS can rebut it only by showing the valuation was grossly unreasonable.

In plain terms, a current independent 409A appraisal moves the burden of proof onto the IRS. That is why venture-backed startups refresh their 409A at least every 12 months and after any material event, such as a priced financing.

For example, a seed-stage company gets a 409A valuation setting common stock at $0.40 per share. It grants options at a $0.40 strike. Because the appraisal is independent and current, the grants sit inside the safe harbor, and the option holders face no Section 409A income or penalty on those grants.

The 409A number values common stock, which is typically worth less than the preferred stock investors buy. It anchors the strike price on every option in the option pool, including each incentive stock option. See equity compensation for how it fits the broader plan.

This is general information, not tax advice.