Step-Up in Cost Basis: Inherited Asset Rules & Examples

A step up in cost basis resets an inherited asset’s tax basis to its fair market value (FMV) on the valuation date (commonly the decedent’s date of death), so the beneficiary measures future taxable gain from that stepped‑up amount rather than the decedent’s original purchase price Fidelity. This typically reduces capital‑gains exposure for appreciation that occurred before the owner’s death.

What Step-Up in Cost Basis Means

Cost basis is the amount used to compute taxable gain or loss when an asset is sold—generally the original purchase price adjusted for allowable items such as acquisition costs or capital improvements, and reduced by allowable depreciation where applicable Fidelity. A “step up” replaces that existing basis with the asset’s FMV on a specific valuation date. For typical inheritances, the heir’s new basis equals the FMV on the decedent’s date of death, making future taxable gain equal to sale proceeds minus that stepped‑up basis Fidelity.

Scope clarifications: the step up is a tax‑basis adjustment, not a cash payment or tax credit; it changes only how future gains are measured Fidelity. It affects unrealized appreciation that accrued before the valuation date and therefore often reduces taxable gain when heirs later sell inherited assets Fidelity.

How It Works

Mechanically, apply three steps. First, determine the triggering event and valuation date—usually the decedent’s date of death for inherited property—and identify the FMV at that date Fidelity. Second, reconcile the decedent’s pre‑death basis: start with original cost and adjust for allowable increases (for example, acquisition costs and capital improvements) and decreases (for example, certain depreciation) Fidelity. Third, set the heir’s basis equal to the FMV used for the step up; future taxable gain equals sale proceeds minus that stepped‑up basis Fidelity.

Practical valuation and recordkeeping points: publicly traded securities commonly use market quotes to establish FMV, while real property and illiquid assets often require a qualified appraisal—retain whichever evidence you used to establish FMV Fidelity. Some transaction costs (for example, brokerage commissions) can increase basis, while routine investment management fees generally do not Fidelity. Finally, the step up only affects tax calculations when a realization event (typically a sale) occurs; it does not change ownership or provide immediate cashflow.

Worked Example

Assumptions:

• Decedent originally bought 100 shares at $20.00 per share (original basis = $2,000).
• FMV on the decedent’s date of death is $150.00 per share (stepped‑up basis = $15,000).
• The heir later sells all 100 shares for $160.00 per share (sale proceeds = $16,000).
• Ignore commissions and minor adjustments for clarity.

Step‑by‑step arithmetic:

1. Decedent’s original basis = 100 × $20.00 = $2,000.
2. Stepped‑up basis at death = 100 × $150.00 = $15,000. The heir’s new basis becomes $15,000.
3. Sale proceeds when the heir sells = 100 × $160.00 = $16,000.
4. Taxable gain to the heir = $16,000 − $15,000 = $1,000.

Interpretation: without the step up, the taxable gain would have been $16,000 − $2,000 = $14,000. With the step up, the heir is taxed only on the $1,000 of post‑death appreciation, effectively sheltering the $13,000 of appreciation that occurred during the decedent’s ownership Fidelity. This hypothetical illustrates how resetting basis at FMV reduces future capital‑gains exposure for pre‑death appreciation.

How to Interpret It

A step up primarily changes tax timing and measurement. If an heir sells soon after inheriting at a price close to the FMV used for the step up, realized taxable gain may be minimal or zero because sale price and stepped‑up basis align Fidelity. If the asset falls below the stepped‑up basis and the heir sells for less, the heir may realize a capital loss, subject to the tax rules governing loss recognition.

Do not conflate basis reset with elimination of all tax consequences. Estate tax, gift tax, state rules, and special treatment for certain trust or lifetime‑gift transactions can still apply; the tax interplay depends on the transfer type and jurisdiction Fidelity. Keep in mind that the step up affects only unrealized appreciation before the valuation date—not subsequent appreciation or income generated after inheritance.

Decision framework (simple): when assessing the importance of a step up for an inherited asset, ask:

1. How liquid is the asset? (Public securities are straightforward; private assets require appraisal.)
2. Is the heir likely to sell soon? (Near‑term sales often realize small gains after a step up.)
3. Are there estate‑tax considerations or special transfer rules? (These can alter outcomes.)
4. Do you have documentation to support FMV and prior basis? (Documentation reduces dispute risk.)

For readers who track multiple purchase dates and averaged bases from regular buying strategies, see our Dollar Cost Averaging glossary entry for how multiple buy prices affect basis tracking Dollar Cost Averaging.