Cost Basis of Inherited Stock: Step-Up Rules & Examples

For inherited stock, “cost basis” usually means the value used to compute gain or loss when you later sell the shares — commonly reset (or “stepped up”) to the security’s fair market value (FMV) at the decedent’s date of death. If you sell later, the taxable gain is the sale price minus that stepped‑up basis; if you keep the shares, no gain is realized until sale..

What Inherited Stock Cost Basis Means

Definition and scope: cost basis for inherited stock is the value assigned to the shares for tax purposes when ownership passes to an heir. In common practice, the basis becomes the FMV of the shares at the date of the decedent’s death; that new basis, not the decedent’s original purchase price, is what determines taxable gain on a later sale.

Scope notes:

• This article covers the typical U.S. treatment and practical implications for an heir who receives publicly traded shares. It explains how the stepped basis affects later gains or losses and the common exceptions you should check. Sources and estate‑specific rules can change outcomes; see the “Limitations and Source Checks” section for what to verify.

How It Works

Mechanics and calculation: the usual mechanic is “step‑up” to FMV at the date of death. Practically that means:

• Determine the FMV of the inherited shares on the decedent’s date of death (or alternate valuation date if the estate qualifies and elects it). Use that FMV as your cost basis.,.
• When you sell, taxable gain (or loss) = sale price − cost basis (adjusted for transaction costs where applicable). If sale price > basis, you normally have a capital gain; if lower, you have a capital loss.

Common calculation steps

1. Identify the security and number of shares inherited.
2. Find the FMV per share at the date of death (price on that date for public stocks).
3. Multiply FMV per share × shares = stepped‑up cost basis.
4. On sale, compute sale proceeds minus cost basis = realized gain or loss.

Practical note about costs and taxes: if you plan to sell inherited securities, expect transaction costs and tax consequences; consider liquidity and fees before acting FINRA. Also consider brokerage or estate fees when comparing net outcomes — for general context on cost types see our Finelo article on Fixed Vs Variable Costs.

Worked Example

Assumptions

• You inherit 100 shares of company XYZ.
• FMV on the decedent’s date of death: $150.00 per share. (This is the stepped‑up basis.)
• You later sell all 100 shares for $170.00 per share.
• Ignore brokerage commissions and small transaction fees for clarity.

Arithmetic

• Stepped‑up cost basis = 100 × $150.00 = $15,000.
• Sale proceeds = 100 × $170.00 = $17,000.
• Realized capital gain = $17,000 − $15,000 = $2,000.

Interpretation

• Taxable capital gain on sale is $2,000. Because your basis was reset to $150, not the decedent’s original purchase price, only the $2,000 difference is subject to capital gains tax when you file. The common rule that the basis equals FMV at date of death explains why heirs often owe little or no tax when selling immediately after inheriting.

How to Interpret It

Key interpretations

• Short holding period: For inherited securities, the holding period is usually treated as long‑term for capital gains treatment, regardless of how long you hold after inheritance. That affects tax rates, if you owe tax on a gain. (See a tax advisor for your jurisdictional rules.)
• Selling immediately vs holding: Selling soon after inheritance often produces little gain if FMV at death ≈ sale price; holding can create future gains or losses measured against the stepped‑up basis.
• Losses: If FMV at date of death becomes your basis, your ability to claim a loss depends on whether the market value later falls below that basis when you sell.

Decision framework (quick)

• If you need liquidity or want to remove concentrated risk, evaluate selling: estimate net proceeds minus likely taxes and transaction fees FINRA.
• If taxes are the primary concern and FMV ≈ sale price, taxes on an immediate sale may be small.
• If you want to preserve potential growth or dividends, weigh opportunity cost vs tax timing and diversification goals.

How It Compares With Related Concepts

Comparison checklist

• Inherited (stepped) basis vs original purchase price: For inherited shares, the dominant practice is using FMV at date of death as basis; the original purchaser’s cost basis is usually irrelevant for the heir’s tax calculation.
• Inherited basis vs gifted property: When stock is gifted during the donor’s lifetime instead of inherited, the recipient usually takes the donor’s original cost basis (carryover basis), which can result in larger taxable gains on sale. (Gifting rules differ from inheritance rules; consult a tax professional.)
• Date‑of‑death value vs alternate valuation date: Estates that file an estate tax return may be able to elect an alternate valuation date, typically six months after death, to value estate assets for both estate tax and basis purposes — that election has conditions and consequences; check estate rules or executor decisions.

Two common misreads and how they fail in practice

1. “No tax ever on inherited assets.” Misread: heirs assume inheritance eliminates all future tax. Reality: inheritance can eliminate prior unrealized gains for the heir (via step‑up), but selling the asset after inheritance can still trigger capital gains measured from the stepped‑up basis.
2. “You always use the sale price on the date of death.” Misread: heirs may not know which date to use. Reality: the usual date is date of death FMV; an alternate valuation date may apply only if the estate files Form 706 and elects the alternate date — that’s an executor/estate decision with limits.