Inherited stock cost basis: step-up rules explained

When you inherit stocks or other securities from someone who has passed away, one of the most important financial and tax concepts you need to understand is the step-up in basis. This rule can dramatically affect the capital gains tax you might owe when you eventually sell those inherited assets. While inheriting property can be emotionally complex, grasping these tax rules is crucial for making informed decisions and avoiding costly surprises.

This guide explains the step-up in basis for inherited stock in plain language, focusing on the U.S. federal tax rules administered by the IRS. It will cover what the step-up is, how to determine your new cost basis, what documents you need, and the practical steps to take when reporting a sale on your tax return. Remember, this is general educational information. Tax rules can change, and your specific situation may vary. Always verify details with the IRS or consult a qualified tax professional for personalized advice.

What Is Cost Basis and Why Does It Matter?

Before diving into the step-up, you need to understand cost basis. In simple terms, cost basis is essentially your investment in a property for tax purposes. For stocks, it's generally the amount you paid for them, including commissions or fees. When you sell an asset, you calculate your capital gain or loss by subtracting this basis from the sale price.

• Capital Gain: Sale Price > Cost Basis. This gain is typically taxable.
• Capital Loss: Sale Price < Cost Basis. This loss may be used to offset other gains or income, within limits.

The cost basis is critical because it determines the size of your taxable gain. A higher basis means a lower taxable gain, and consequently, less tax owed. This is where the step-up in basis rule becomes a powerful tool for heirs.

The Step-Up in Basis Rule Explained

The step-up in basis (sometimes called a "step-up" or "basis adjustment") is a provision in the U.S. tax code that applies to assets inherited from a deceased person. When you inherit property, including stocks, bonds, or mutual funds, the IRS does not use the original price the deceased person (the decedent) paid. Instead, your cost basis is "stepped up" (or sometimes "stepped down") to the fair market value (FMV) of the asset on the date of the decedent's death.

There is an important alternative: the executor of the estate may elect to use the alternate valuation date, which is generally six months after the date of death. This is rare and typically only used if it lowers the total value of the estate for estate tax purposes. For most taxpayers, the date-of-death value is the relevant one.

Why does this matter? It effectively eliminates the capital gains tax on any appreciation that occurred during the deceased person's lifetime. You are only responsible for tax on gains that happen after you inherit the asset.

A Simple Step-Up Example

Imagine your mother purchased 100 shares of XYZ Corp. decades ago for $10 per share, a total cost basis of $1,000. On the date she passed away, the stock was trading at $150 per share, making the fair market value $15,000.

• Your Inherited Cost Basis: $15,000 (the date-of-death value).
• If you sell immediately for $15,000, your gain is $0 ($15,000 sale - $15,000 basis). You owe no capital gains tax.
• If you hold the stock and later sell it for $20,000, your taxable gain is $5,000 ($20,000 sale - $15,000 basis). You are only taxed on the $5,000 of growth that occurred while you owned it.

Without the step-up rule, your basis would have been her original $1,000. Selling for $20,000 would have meant a taxable gain of $19,000.

Determining the Fair Market Value for Inherited Stock

Establishing the correct date-of-death value is your most important task. For publicly traded stocks and mutual funds, this is straightforward. The fair market value per share is generally the average of the high and low trading prices on the date of death. If the date of death was on a weekend or holiday when the markets were closed, use the average of the high and low prices on the nearest trading day before and after the date of death.

You can obtain historical price data from financial websites, your brokerage, or through services that specialize in this information. Your brokerage handling the inherited account will often calculate and report this basis to you, especially for accounts transferred after 2011, due to cost basis reporting rules.

For privately held stock, determining FMV is more complex and usually requires a valuation from a qualified appraiser, often arranged by the estate's executor.

What Is Your Holding Period?

Another benefit of inheriting assets is that they are automatically considered long-term property, regardless of how long you or the decedent held them. This is significant because long-term capital gains are taxed at lower, preferential rates (0%, 15%, or 20%) than short-term gains, which are taxed as ordinary income. When you file, you will report the sale of inherited property as a long-term transaction.

Documents You Need: An Inherited Stock Checklist

Proper documentation is non-negotiable. You must be able to prove your stepped-up basis to the IRS if questioned. Here is a checklist of key documents to gather and retain:

• The death certificate: The official document establishing the date of death.
• The account statement from the date of death: This should show the holdings and is often the starting point for determining value.
• Historical price records: Documentation showing the high, low, and average trading price for each security on the date of death. Save printouts or PDFs from reliable sources.
• The estate's valuation documents: If you are a beneficiary, the executor should provide documentation of the asset values used for the estate. This may be on Form 8971 or a supplemental schedule.
• The new account statement in your name: Showing the transfer of the assets from the estate or deceased's account to your inherited account or beneficiary account.
• The final sale confirmation: When you sell, keep the trade confirmation showing the sale date, number of shares, and net proceeds.

Keep these records permanently, or at least for as long as you own the asset plus seven years after you file the return reporting its sale. Good recordkeeping is your best defense in case of an IRS inquiry.

Reporting the Sale of Inherited Stock on Your Tax Return

When you sell inherited stock, you report the transaction on IRS Form 8949, Sales and Other Dispositions of Capital Assets, and then summarize the totals on Schedule D (Form 1040).

You will need to provide: 1. A description of the stock (e.g., "100 sh. XYZ Corp."). 2. The date you acquired it (which, for inheritance, is the date of death). 3. The date you sold it. 4. Your sales proceeds (the net amount after commissions). 5. Your cost basis (the stepped-up fair market value from the date of death). 6. The resulting gain or loss.

Crucially, you must check box E on Form 8949, which indicates the property was inherited. This signals to the IRS that you are using a stepped-up basis and a long-term holding period, even if you sold the asset shortly after inheriting it.

Most brokerages now provide a Form 1099-B when you sell securities. For inherited assets, the basis reported on this form may be incorrect if the brokerage does not have the stepped-up value in their system. It is your responsibility to adjust the basis on your Form 8949 to the correct stepped-up amount, even if the 1099-B shows a different number. Always compare your records to the 1099-B.

Special Considerations and Complex Scenarios

The basic step-up rule is clear, but several situations add complexity.

Community Property States

If the deceased lived in a community property state (Arizona, California, Idaho, Louisiana, Nevada, New Mexico, Texas, Washington, Wisconsin), assets owned jointly with a spouse may receive a full step-up in basis for both halves of the community property upon one spouse's death. This differs from common law states, where typically only the deceased spouse's half of jointly-owned property gets a step-up.

Assets Received as a Gift Before Death vs. Inheritance

This is a critical distinction. Assets you received as a gift from a living person do not get a step-up in basis. You generally take the donor's original cost basis and holding period. The step-up rule applies only at death. If you are unsure whether assets were a gift or an inheritance, review the estate documents carefully.

The "Step-Down" in Basis

If an asset's fair market value has fallen below its original cost by the date of death, the basis is "stepped down" to that lower value. This can create a smaller potential loss for you if the value later recovers. It's the same rule, just applied to a depreciated asset.

Estate Tax Filing Thresholds

For very large estates, federal estate tax may apply. For deaths in 2024, the estate tax exemption is $13.61 million per individual. Most estates fall well below this threshold and do not file a federal estate tax return (Form 706). However, the step-up in basis applies regardless of whether an estate tax return is filed. Some states have much lower thresholds for state estate or inheritance taxes, which are separate from the basis step-up rules.

When to Seek Help from a Tax Professional

While this guide covers the fundamentals, your situation may warrant professional advice. Consider consulting a qualified tax advisor, such as an Enrolled Agent (EA), Certified Public Accountant (CPA), or tax attorney, in these scenarios:

• The estate is large or complex, involving trusts, multiple types of assets, or potential estate tax filings.
• You inherited privately-held stock, a business interest, or hard-to-value assets.
• You are unsure about the correct date-of-death value or cannot locate the necessary records.
• You received conflicting information from a brokerage or the estate executor regarding your basis.
• You are selling only a portion of the inherited holdings over time and need help with specific identification of shares.
• You receive an IRS notice questioning the basis you reported on your tax return.

A professional can help ensure your basis is calculated correctly, the proper elections are made, and your tax filings are accurate. They can also assist with state-specific inheritance rules, which can vary.

Final Practical Steps and Reminders

Dealing with inheritance is challenging. To navigate the tax aspects calmly and correctly, focus on these steps:

1. Do not rush to sell. Take time to understand your new cost basis and the tax implications. Emotional decisions can lead to unintended tax consequences.
2. Secure the documentation. Use the checklist provided earlier to gather all statements, valuations, and legal documents. Create a dedicated file for these records.
3. Contact the brokerages. Inform them of the account holder's death and initiate the transfer process. Ask them how they will report the cost basis for the inherited securities.
4. Verify the basis yourself. Do not assume the number on a statement is final. Independently verify the date-of-death fair market value for key holdings.
5. Report sales accurately. When you file, use Form 8949 and Schedule D, check the "inherited" box, and report your correct stepped-up basis, even if it differs from your 1099-B.
6. Keep state taxes in mind. While this article focuses on federal rules, remember that your state may have its own income tax rules for capital gains. Verify with your state's tax agency.
7. Beware of tax scams. After a death, scammers may target survivors. The IRS will never initiate contact via email, text, or social media to demand immediate payment or personal information. All official correspondence comes by mail. If you are unsure about a notice, verify it independently via IRS.gov.

Understanding the step-up in basis rule empowers you to manage an inherited portfolio wisely. By establishing the correct cost basis, maintaining thorough records, and reporting sales properly, you can fulfill your tax responsibilities and make the most of the legacy you've received. For the most current information and forms, always refer to the official IRS website at IRS.gov, specifically topics related to capital gains and losses.

About the TDL Expert Panel

TDL Expert Panel · TheDigitalLife Editorial Team

TDL Expert Panel is the editorial team behind TheDigitalLife. The team researches, reviews, and creates practical guides to help everyday readers make better decisions about home repair costs, refunds, AI tools, digital safety, productivity, and useful online resources. Each guide is written to be clear, useful, and easy to understand.

Contact TheDigitalLife