409A Valuation After an Acquisition: Whose Stock Gets Appraised?
Author: Redwood Valuation Content Team
Published: September 2, 2026
After an acquisition, §409A treats existing target options differently from new options granted after closing. Existing target options may be assumed or replaced as part of the deal. If a rollover results in an option on acquirer stock, two FMV-based tests use the target stock's fair market value immediately before the change and the acquirer's fair market value immediately after it. New options on acquirer stock instead use the acquirer's fair market value on the grant date.
What Changes at Closing, and What This Article Doesn't Cover
A previously calculated 409A valuation is not reasonable to use if it is more than 12 months old or does not reflect later information that may materially affect value. This article focuses only on §409A issues that arise after an acquisition closes. It does not address when pre-closing developments require an existing valuation to be updated.
When an Assumed or Substituted Option Is Not a New Grant
An acquirer can assume a target option or replace it with a new option without creating a new §409A grant if the rollover qualifies under the applicable rules. In broad terms, the change must occur because of a covered corporate transaction and must satisfy the rollover requirements in §1.424-1, as modified for §409A. The two FMV-based tests are explained below.
When the rollover qualifies, the existing option is not treated as a brand-new §409A grant. The share count or exercise price may change, but the other terms generally carry over unless the transaction makes a term inoperative. The rollover also cannot add benefits the old option did not have.
If the rollover does not qualify, the replacement option may be treated as a new grant. To stay outside §409A under the stock-option exclusion, the new option must then satisfy the applicable requirements on its own grant date. Those requirements include eligible stock, an exercise price at least equal to grant-date FMV, and no impermissible deferral feature. FMV pricing alone is not enough.
The Two FMV Tests for a Rollover
The valuation part of the rollover analysis has two separate tests. The first limits the option's total built-in gain, or "aggregate spread." The second compares the exercise price with FMV on a per-share basis. Both tests use the target stock's FMV immediately before the option change and the acquirer's stock FMV immediately after it. Passing one test does not satisfy the other.
The first test limits aggregate spread. Spread is simply the option's built-in gain: the total FMV of the shares covered by the option minus the total exercise price for those shares. The rollover cannot increase that amount. If the option has $8,000 of spread immediately before the rollover, it cannot have more than $8,000 immediately afterward.
The second test looks at the exercise price as a percentage of FMV on each side of the rollover. For §409A, §1.409A-1(b)(5)(v)(D) treats this condition as satisfied if the exercise-price-to-FMV ratio immediately after the change is not greater than the ratio immediately before.
| Condition | In plain English | FMVs needed |
|---|---|---|
| Aggregate spread (§1.424-1(a)(5)(ii)) | Total built-in gain after the rollover cannot exceed total built-in gain before it | Target stock before; acquirer stock after |
| Share-by-share ratio (§1.409A-1(b)(5)(v)(D); §1.424-1(a)(5)(iii)) | For §409A, exercise price ÷ FMV after the rollover cannot be greater than the ratio before the rollover | Target stock before; acquirer stock after |
For example, assume an option covers 1,000 target shares at a $2.00 exercise price and the target's common stock is worth $10.00 immediately before closing. The aggregate spread is $8,000. Now assume the rollover changes the option to 500 acquirer shares at a $4.00 exercise price and the acquirer's common stock is worth $20.00 immediately after the change. The aggregate spread is still $8,000, and the exercise-price-to-FMV ratio is 0.20 both before and after. In this example, both FMV tests are satisfied. The figures are hypothetical and chosen for simple arithmetic.
Merger agreements often adjust the option using an exchange ratio:
Assumed share count = target share count × the exchange ratio
Assumed exercise price = target exercise price ÷ the exchange ratio
Using the same exchange ratio in both calculations preserves the option's total exercise price. But that arithmetic alone does not show that the two FMV tests are satisfied. You still need the target stock's FMV immediately before the change and the acquirer's stock FMV immediately after it.
If the acquirer is private, these tests may require a supportable value for its stock immediately after the option change. If no current analysis supports that value, additional valuation work may be needed. Closing the deal, by itself, does not require a separate appraisal.
New Options for Employees of the Acquired Company
Employees of the acquired company can often receive new options on the acquirer's stock. For a new option to qualify for the §409A stock-option exclusion, the stock must qualify as "service recipient stock." In practical terms, the rules look at the ownership relationship between the employee's employer and the company issuing the stock.
For the ordinary rule, each step in that ownership chain generally must meet a 50% controlling-interest threshold. A 20% threshold can apply when legitimate business criteria support the grant. These ownership rules apply to new grants; qualifying rollovers of existing options follow the separate rollover rules above.
If the target becomes a wholly owned subsidiary of the acquirer, the ownership test is usually straightforward because the acquirer owns more than the ordinary 50% threshold. More complicated structures need a closer look.
Examples include:
Joint ventures, where no single parent may meet the required ownership threshold
Minority-stake acquisitions that may not reach the threshold
Partial roll-ups where ownership is divided among several entities
Holding-company structures with intermediate entities between the employee's employer and the option issuer
These structures do not automatically disqualify a grant. But the ownership percentages and entity relationships should be mapped before the option is issued to confirm that the issuer qualifies under the service-recipient-stock rules.
If the stock does not qualify, the option generally falls outside the stock-option exclusion and may instead be treated as deferred compensation subject to §409A. That is why the ownership relationship should be checked before the grant is made.
How to Value New Grants on Acquirer Stock
To qualify for the §409A stock-option exclusion, a new nonstatutory option on acquirer stock must, among other things, have an exercise price at least equal to the FMV of qualifying service recipient stock on the grant date and avoid impermissible deferral features. For private-company stock, §409A does not prescribe a single valuation technique. The company must use a reasonable valuation method and apply it reasonably.
For a post-close grant, the practical questions are:
Are you using acquirer common stock that qualifies as service recipient stock?
What is that stock worth on the grant date?
Is the valuation method reasonable for the facts and applied reasonably?
The grant date is not necessarily the closing date. It is the date when the granting corporation completes the action needed to create the legally binding option, after the maximum number of shares and minimum exercise price are fixed or determinable and the stock class and recipient are identified. Merely approving an option pool does not, by itself, establish the grant date.
The target's old 409A valuation does not carry over to a new grant on the acquirer's stock. It values different stock. The new option must be priced using the acquirer's FMV on the grant date.
If the acquirer already has a recent 409A valuation, the question is whether it is still reasonable on the new grant date. Closing does not automatically invalidate that valuation or restart the 12-month period. But information arising from the acquisition may make the valuation stale sooner if it materially affects value.
Why the Acquisition Price Does Not Automatically Become the 409A Value
The acquisition price and a §409A valuation measure different things. The deal price is negotiated consideration for the target transaction. A §409A valuation determines the FMV of a particular class of the acquirer's stock as of a particular date.
| The acquisition price reflects… | A §409A valuation focuses on… |
|---|---|
| The target transaction as negotiated | A specific class of the acquirer's stock |
| Consideration paid under the deal terms | Fair market value as of the relevant valuation date |
| Deal economics that may include control or expected synergies | The rights and attributes of the acquirer's common stock |
| The target being acquired | The acquirer stock underlying the options |
Information from the acquisition can still matter because the transaction may affect the acquirer's value. Those effects should be reflected in the §409A analysis when relevant. But the deal price for the target should not simply be carried over as the §409A value of the acquirer's stock.
ASC 805 Is a Separate Valuation Exercise
ASC 805 purchase accounting and a §409A valuation serve distinct purposes. ASC 805 measures the acquisition for financial reporting. Section 409A determines the FMV of stock used for equity compensation. The acquirer's stock value may sometimes be an input when stock is part of the purchase consideration under ASC 805, but the purchase price allocation does not otherwise determine the §409A value of the acquirer's common stock.
Closing Thoughts
After closing, keep the rollover and new-grant analyses separate. Existing target options can keep their prior §409A treatment if the assumption or replacement satisfies the rollover rules. New options on the acquirer's stock are tested as new grants and use the acquirer's FMV on the grant date.
Both analyses may require a supportable value for the acquirer's stock, but at different times: immediately after the option change for a rollover and on the grant date for a new option.
Section 409A does not require a valuation within a fixed number of days after closing. The relevant date comes from the option change or grant being analyzed.
Frequently Asked Questions
Do you need a new 409A after an acquisition?
Not automatically. Closing alone does not require a new valuation. A rollover may require supportable values for the target stock immediately before the option change and the acquirer's stock immediately after it. A new option on acquirer stock uses the acquirer's FMV on the grant date. An existing valuation can continue to be used only while it remains reasonable, including the 12-month and material-information limits.
What happens to stock options when a company is acquired?
If the acquirer assumes an outstanding option or replaces it with an option on acquirer stock, a qualifying rollover can preserve the option's existing §409A treatment. In other words, the rollover itself is not treated as a brand-new grant. But the rollover still requires the before-and-after FMV tests described above.
Does the exercise price on our options change in the deal?
Often, but not always. Merger agreements commonly use an exchange ratio to adjust both the number of shares and the exercise price. Those adjustments do not replace the FMV tests. The option's total built-in spread after the change cannot exceed the spread before it, and for §409A the exercise-price-to-FMV ratio after the change cannot be greater than the ratio before.
Does the acquisition price become our new 409A value?
Not necessarily. The acquisition price is negotiated consideration for the target transaction, while a §409A valuation for options on acquirer stock measures a particular class of the acquirer's stock at FMV. Information from the transaction may affect that valuation, but the deal price alone does not establish the acquirer's §409A value.
Can the target's old 409A valuation be used for new options on the acquirer's stock?
Not as the value used to price the new grant. A new option on the acquirer's stock uses the FMV of qualifying acquirer stock on the grant date. The target's old valuation relates to different stock and therefore does not carry over.
About Redwood Valuation
Redwood Valuation Partners provides independent valuation services to private companies and their advisors, including 409A valuations for equity compensation. If you are working through an option assumption or planning the first grant on the acquirer's stock after a deal, contact Redwood to talk through the specifics of your structure.