How to Calculate Fair Market Value of Stock for Tax Purposes

To calculate the fair market value of stock for tax purposes, use the average of the highest and lowest selling prices on the valuation date for publicly traded shares, or apply a formal business valuation method (market, income, or asset-based) for private company shares. The valuation date depends on the filing: date of death for an estate, date of transfer for a gift, date of contribution for a charitable donation, and grant date for an employee stock option. The method is set by federal tax regulations, and the number you report drives your tax bill.

Publicly Traded Stock

For shares that trade on an exchange like the NYSE or NASDAQ, federal regulations require the mean between the day’s highest and lowest quoted selling prices on the valuation date. If the stock hit a high of $50 and a low of $48, the fair market value is $49 per share. The closing price, opening price, and intraday swings don’t factor in.¹

This same mean-price rule applies whether you’re filing an estate tax return, a gift tax return, or claiming a charitable deduction. On Form 706, executors report stock holdings on Schedule B using this calculation.²

When the Valuation Date Falls on a Non-Trading Day

If the valuation date is a weekend or federal holiday, no trades occurred and no mean price exists. You then take a weighted average of the mean prices from the nearest trading days before and after the valuation date. The weighting runs inversely to the number of trading days between each sale date and the valuation date, so the closer trading day carries more weight. When the valuation date sits exactly between the two trading days, the weighted average collapses into a simple average.¹

Large Holdings and the Blockage Discount

When an estate or foundation holds a block of publicly traded shares so large that selling them at once would depress the market price, a blockage discount may apply. The premise is that the quoted price assumes a normal-sized lot. Establishing a blockage discount requires expert evidence tying the block’s size to the stock’s typical trading volume. For private foundation minimum investment returns, the IRS caps the combined reduction for blockage and similar factors at 10% of the shares’ quoted fair market value.³

The Alternate Valuation Date for Estates

Executors have a second option when stock values have fallen since the date of death. Under 26 USC 2032, the executor can elect to value all estate assets as of six months after the decedent’s death. Property the estate sold, distributed, or otherwise disposed of during that six-month window is valued on the date it left the estate.⁴

Two requirements are strict. The election must decrease both the gross estate value and the total estate tax liability; you can’t use it just to boost stepped-up basis. And the election is made on Form 706 and is irrevocable once made. If the return is filed more than one year after the extended filing deadline, the election is gone.⁴

Private or Closely Held Stock

Without a public market quoting a daily price, valuation becomes an analytical exercise. The foundational IRS guidance is Revenue Ruling 59-60, which identifies eight factors an appraiser must weigh when valuing shares in a closely held company:⁵

The nature and history of the business
The economic outlook for the general economy and the specific industry
Book value and financial condition
Earning capacity, both historical and projected
Dividend-paying capacity
Goodwill and other intangible value
Prior sales of the company’s stock and the size of the block being valued
Market prices of comparable publicly traded companies

No single factor controls. The appraiser weighs all eight against the specific facts, then applies one or more of three formal approaches: market, income, or asset-based. Most credible valuations use at least two and reconcile the results.

The Market Approach

The market approach estimates value from what investors pay for similar businesses. The Guideline Public Company method compares the subject company to publicly traded firms with similar size, industry, growth, and risk profile. The Guideline Transaction method looks at actual acquisition prices from recent mergers of comparable businesses. Either way, the analyst derives a valuation multiple (such as enterprise value to EBITDA, or price to earnings) from the comparable data and applies it to the subject company’s own financial metric. If comparables trade at five times EBITDA and the subject company generates $1,000,000 in EBITDA, the preliminary enterprise value is $5,000,000. The method depends on the quality of the comparable set. Niche industries with few peers or few recent transactions weaken it.

The Income Approach

The income approach values a business on the cash it is expected to generate, discounted to present value. The discounted cash flow (DCF) method projects free cash flows over a forecast period (usually five years), discounts each year back to the present using a rate that reflects the risk of those future dollars, and adds a terminal value for the business’s worth beyond the forecast period. The weighted average cost of capital is the common discount rate.

For companies with stable, predictable earnings, the capitalization of earnings method is a simpler alternative. You divide a single representative earnings figure by a capitalization rate equal to the discount rate minus the expected long-term growth rate. A discount rate of 25% and expected growth of 5% produces a 20% cap rate; $200,000 in normalized earnings divided by 20% yields a $1,000,000 value. The income approach tends to work well for profitable, growing companies and poorly for early-stage businesses with negative or erratic cash flow.

The Asset-Based Approach

The asset-based approach tallies what the company owns and subtracts what it owes. Start with the balance sheet, then adjust book values to current market prices: real estate that has appreciated, equipment that has depreciated below its book value, obsolete inventory. Add identifiable intangibles that carry commercial value, such as patents, trademarks, customer lists, and proprietary technology. The IRS specifically notes that goodwill should be considered when valuing an interest in a closely held business.⁶ Subtract the fair market value of liabilities, and the remainder is equity value. This approach suits asset-heavy companies (real estate holding firms, investment companies, liquidations) and tends to undervalue businesses whose worth sits in earnings power or brand.

Discounts That Reduce the Private-Stock Number

Raw numbers from the three approaches almost always require adjustment before they represent what a specific block of private shares is worth.

The Discount for Lack of Marketability (DLOM) accounts for the fact that private shares can’t be sold with a few clicks. Finding a buyer, negotiating, and closing take time, and the seller carries the risk of market changes along the way. Empirical studies of restricted stock and pre-IPO transactions consistently show discounts in the range of 15% to 35% for most situations, with higher discounts sustained where restrictions or holding periods are severe.⁷

The Discount for Lack of Control (DLOC) reflects that a minority shareholder cannot set compensation, declare dividends, sell the company, or steer strategy. Its size depends on the rights attached to the shares, the governance structure, and any shareholder agreement provisions (tag-along rights, supermajority requirements) that hand minority holders some protective power. For gift and estate tax purposes, this discount can meaningfully lower the taxable value of transferred interests. A control premium runs the other direction when valuing a majority stake, and the acquisition-premium data analysts use to derive minority discounts comes from the same source.

Section 409A Valuations for Employee Stock Options

A private company that issues stock options to employees must set the exercise price at or above the stock’s fair market value on the grant date. If the exercise price is too low, the options are treated as deferred compensation under Section 409A of the Internal Revenue Code. The tax consequences fall on the employee: the deferred amounts become taxable at vesting rather than exercise, a 20% penalty tax applies on top of ordinary income tax, and interest accrues on the underpaid tax going back to the year the compensation was first deferred.⁸

To sidestep that outcome, private companies obtain a “409A valuation.” The IRS provides safe harbor methods that create a presumption of reasonableness. The most common is an independent appraisal from a qualified third party meeting the same standards applied to retirement plan valuations. Early-stage startups with limited operating history and no significant revenue can use a reasonable valuation method that accounts for all available material information about the company, subject to more specific eligibility rules. A 409A valuation generally stays valid for 12 months unless a material event (a new funding round, a major acquisition) significantly changes the company’s value.

Filing Requirements and Qualified Appraisals

p>Executors report stock holdings on Schedule B of Form 706. Actively traded shares get the mean-price calculation; closely held or inactive corporations require full valuation details.²

For charitable donations of non-publicly-traded stock worth more than $5,000, a qualified appraisal is required, and the donor must attach Form 8283 (Noncash Charitable Contributions) to the return. Publicly traded securities with readily available market quotations are exempt from the qualified appraisal requirement.⁹

A qualified appraiser is someone with verifiable education and experience in valuing the type of property being appraised. That means either college-level coursework in the relevant field plus at least two years of hands-on experience, or a recognized professional designation from an appraiser organization. The appraiser must also not have been barred from practicing before the IRS at any point during the three years before signing the appraisal.¹⁰

Penalties for Getting the Number Wrong

A substantial valuation misstatement occurs when the value you claim is 150% or more of the correct value. The penalty is 20% of the resulting tax underpayment. A gross valuation misstatement, where the claimed value is 200% or more of the correct amount, doubles the penalty to 40%. Neither penalty kicks in unless the underpayment attributable to the misstatement exceeds $5,000 ($10,000 for C corporations).¹¹ The 20% and 40% rates apply only to the portion of the underpayment caused by the misstatement, not the entire tax bill.¹²

Section 409A adds its own layer for underpriced options: immediate income inclusion at vesting, a 20% penalty tax, and interest running from the year the compensation was first deferred. Again, the employee pays, not the company.⁸

What a Professional Valuation Costs

For private company stock, most people will need an appraiser rather than doing the math themselves. Fees vary with company size, complexity, and purpose. Simple valuations for small businesses with straightforward financials start around $2,500 to $5,000. Mid-sized companies with more complex capital structures or multiple business lines run $10,000 to $25,000. Valuations prepared for litigation or contentious partner disputes routinely run $15,000 to $40,000 or more, because the appraiser must be prepared to defend the work under cross-examination. A 409A valuation for a startup issuing options usually sits at the lower end because the financial history is short and the scope is narrower. Set against IRS penalties that can reach 40% of the tax underpayment, a defensible valuation is cheap insurance.

1
GovInfo. 26 CFR 20.2031-2 – Valuation of Stocks and Bonds
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Internal Revenue Service. Instructions for Form 706
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Internal Revenue Service. Reduction in Value for Blockage or Similar Factors in Asset Valuation
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Office of the Law Revision Counsel. 26 USC 2032 – Alternate Valuation
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Internal Revenue Service. Valuation of Assets
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Internal Revenue Service. Publication 561, Determining the Value of Donated Property
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Internal Revenue Service. Discount for Lack of Marketability Job Aid
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Office of the Law Revision Counsel. 26 USC 409A – Inclusion in Gross Income of Deferred Compensation Under Nonqualified Deferred Compensation Plans
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Internal Revenue Service. Charitable Organizations – Substantiating Noncash Contributions
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eCFR. 26 CFR 1.170A-17 – Qualified Appraisal and Qualified Appraiser
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Office of the Law Revision Counsel. 26 USC 6662 – Imposition of Accuracy-Related Penalty on Underpayments
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eCFR. 26 CFR 1.6662-2 – Accuracy-Related Penalty