No, you do not have to file Form 706 to get a step-up in basis on inherited property. The basis adjustment happens automatically under Internal Revenue Code Section 1014 the moment an asset passes to a beneficiary, regardless of the estate’s size and regardless of whether an estate tax return is ever filed.1Office of the Law Revision Counsel. 26 U.S. Code 1014 – Basis of Property Acquired From a Decedent Form 706 is the federal estate tax return. Its job is to calculate estate tax liability, not to activate the basis change.
How the Step-Up Actually Happens
When you inherit an asset, your tax basis becomes its fair market value on the date the prior owner died. That new basis replaces whatever the decedent originally paid. If someone bought stock for $10,000 decades ago and it was worth $500,000 at death, you inherit it with a $500,000 basis. Sell it soon after for $505,000 and your taxable gain is $5,000, not $495,000.
The rule runs in both directions. If the property lost value during the decedent’s lifetime, your basis steps down to the lower date-of-death value. The statute says “fair market value at the date of death” whether that number is higher or lower than the original purchase price.
The step-up also carries a holding-period benefit. Under IRC Section 1223, inherited property sold within a year of the decedent’s death is automatically treated as held for more than one year, so any gain qualifies for long-term capital gains rates.2Office of the Law Revision Counsel. 26 U.S. Code 1223 – Holding Period of Property
One boundary worth naming: tax-deferred retirement accounts do not get a step-up. Traditional IRAs, 401(k)s, pensions, and annuities pay out as ordinary income to the beneficiary, just as they would have to the original owner. Cash and certificates of deposit also fall outside the basis-adjustment rules.
When Form 706 Is Actually Required
Executors must file Form 706 only when the gross estate, combined with any lifetime taxable gifts, exceeds the federal exclusion. For decedents dying in 2026, that threshold is $15 million per individual.3Internal Revenue Service. What’s New – Estate and Gift Tax
The One Big Beautiful Bill Act, signed on July 4, 2025, raised the exclusion from its 2025 level of $13.99 million and eliminated the scheduled sunset that would have cut the amount roughly in half at the end of 2025.3Internal Revenue Service. What’s New – Estate and Gift Tax The gross estate for this calculation is broad: real estate, investment accounts, life insurance proceeds, business interests, and retirement accounts all count. Even so, the great majority of estates fall well below $15 million.
The point for basis purposes: if the estate is under the threshold and no Form 706 is required, beneficiaries still get the full stepped-up basis. Section 1014 operates independently of the estate tax system.
Situations Where Filing Form 706 Does Matter
Three narrow scenarios connect Form 706 to a beneficiary’s basis or to real dollars left on the table. None of them changes the general answer above, but each is worth understanding before deciding whether to file voluntarily or how to handle a return that must be filed anyway.
The Alternate Valuation Date
Under IRC Section 2032, an executor can elect to value estate assets six months after the date of death rather than on the date of death itself.4Office of the Law Revision Counsel. 26 U.S. Code 2032 – Alternate Valuation If an asset was sold or distributed within that six-month window, it is valued as of that transaction date. The election can only be made on a filed Form 706, and it is available only when it reduces both the gross estate and the total estate and generation-skipping transfer taxes owed. Non-taxable estates cannot use it.
When the election is made, the beneficiary’s stepped-up basis shifts to the alternate valuation date value instead of the date-of-death value. In a falling market, that produces a lower basis and a larger future capital gain. The election is irrevocable, so executors of taxable estates should model both outcomes before choosing.
The Consistent Basis Rule
Once a Form 706 is filed, IRC Section 1014(f) requires beneficiaries to report a basis no higher than the value used on the estate tax return. The rule stops the executor from understating asset values to reduce estate tax while the beneficiary claims a high stepped-up basis to reduce capital gains later.
Executors of filing estates must also file Form 8971 and send each beneficiary a Schedule A showing the estate tax value of everything that person receives. If you get a Schedule A, the value on it becomes your basis ceiling. This rule applies only when a Form 706 was actually filed; for estates below the threshold that never file, beneficiaries establish basis on their own.5Internal Revenue Service. Gifts and Inheritances
Portability for a Surviving Spouse
Portability lets the unused portion of a deceased spouse’s exclusion, called the Deceased Spousal Unused Exclusion or DSUE amount, transfer to the surviving spouse. If a spouse dies in 2026 with a $3 million taxable estate, the remaining $12 million of their exclusion can pass to the survivor, giving the surviving spouse a combined $27 million shield against estate tax.
Making the election requires filing Form 706, even when the estate is far below the filing threshold and owes no tax.6Internal Revenue Service. Frequently Asked Questions on Estate Taxes Portability is the most common reason a non-taxable estate files voluntarily. It has nothing to do with the step-up, which the surviving spouse and any other beneficiaries receive regardless. But for couples whose combined wealth may eventually approach the exclusion, skipping the filing is an expensive oversight.
The standard portability deadline is nine months after the date of death, extendable by six months on a timely Form 4768.7Internal Revenue Service. About Form 4768, Application for Extension of Time To File a Return and/or Pay U.S. Estate (and Generation-Skipping Transfer) Taxes For estates below the filing threshold, Revenue Procedure 2022-32 provides a simplified late-election procedure allowing Form 706 to be filed for portability up to five years after death. The return must carry the notation “FILED PURSUANT TO REV. PROC. 2022-32 TO ELECT PORTABILITY UNDER ยง 2010(c)(5)(A)” at the top.8Internal Revenue Service. Revenue Procedure 2022-32
Documenting Basis When No Form 706 Is Filed
If the estate does not file, proving the stepped-up basis is the beneficiary’s job. The IRS can challenge the basis you report when you eventually sell, and you carry the burden of proof. Solid documentation gathered near the date of death is far easier to produce than a reconstruction years later.
For real estate, get a professional appraisal dated close to the date of death, stating the valuation date, methodology, and appraiser qualifications. Fees typically run from $300 to $1,500 or more depending on the property. For publicly traded stocks and mutual funds, the closing price on the date of death is the fair market value; keep brokerage statements or printouts documenting that specific closing price. Most brokerages will adjust the basis in an inherited account once notified, but keep your own records too. Business interests, collectibles, and other hard-to-value property need formal appraisals from someone qualified in that asset class and, ideally, working under the Uniform Standards of Professional Appraisal Practice.
Ask the executor for a written statement of the date-of-death fair market value for every asset you inherit before the estate is closed. Keep everything until the statute of limitations expires for the tax year in which you sell, generally three years after that return is filed.9Internal Revenue Service. Topic No. 305, Recordkeeping Hold an inherited asset for twenty years and you need the documentation for twenty years plus three.
Penalties for Overstating Basis
Inflating a stepped-up basis to shrink a capital gain has real consequences. The IRS imposes a 20% accuracy-related penalty on any underpayment caused by negligence, disregard of tax rules, or a substantial understatement of income tax.10Internal Revenue Service. Accuracy-Related Penalty For individuals, a substantial understatement means you understated your tax by the greater of 10% of the correct tax or $5,000.
When the basis you claim is 400% or more of the correct amount, the penalty doubles to 40% as a gross valuation misstatement. Property whose correct basis is zero is automatically treated as a gross misstatement. Penalties come on top of the additional tax and interest owed. A contemporaneous appraisal from a qualified professional generally protects you even if the IRS later disagrees with the value, because the penalty requires negligence or disregard rather than honest differences of professional opinion.