The ‘Step-Up’ Oversight: The Estate Document Many Wills Still Don’t Include for 2026 Tax Accuracy

Estate planning can be complicated, but many people completely miss the step-up in basis rules that can impact your heirs. Pexels

Many families spend years creating wills, trusts, and beneficiary designations, believing their estate plans are complete. Yet when heirs eventually inherit property, investment accounts, or other valuable assets, a surprisingly common problem emerges: no one can clearly document the asset’s date-of-death value. That missing information can create confusion, delays, and potentially higher capital gains taxes when inherited assets are sold.

Unfortunately, many families overlook a critical document that helps establish a proper step-up in basis, one of the most valuable tax benefits available to heirs. As estate settlements continue to grow more complex, this oversight can be costly if it is not addressed before it becomes a problem. Here’s what you need to know about step-up in basis and how it could impact your estate planning.

What Is a Step-Up in Basis?

A step-up in basis is a tax rule that adjusts the value of inherited assets to their fair market value on the date of the owner’s death. This adjustment can significantly reduce capital gains taxes when heirs eventually sell inherited property or investments.

For example, if a parent purchased stock decades ago for $10,000 and it is worth $100,000 at death, the beneficiary’s new basis may become $100,000. If the heir sells shortly afterward for approximately that amount, little or no capital gains tax may be owed. Because of its potential tax savings, the step-up in basis remains one of the most important concepts in estate planning.

The Missing Document Is Often a Date-of-Death Valuation Report

Many wills specify who inherits assets but fail to include instructions regarding valuation documentation. Estate attorneys frequently recommend obtaining a formal date-of-death valuation report for significant assets such as real estate, closely held businesses, collectibles, and investment portfolios. This report helps establish the fair market value used for calculating the step-up in basis. Without reliable documentation, beneficiaries may struggle years later when trying to determine the proper tax basis for an inherited asset. The longer the delay, the harder it often becomes to reconstruct accurate values.

Real Estate Creates Some of the Biggest Problems

Inherited homes are among the most common assets affected by the step-up in basis rules. Imagine a house purchased in 1985 for $80,000 that is worth $450,000 when inherited in 2026. Without documentation showing the property’s fair market value at the owner’s death, heirs may face challenges proving their adjusted basis when they eventually sell. In some cases, beneficiaries must hire appraisers years later to estimate historical values, which can be expensive and less precise. Maintaining a date-of-death appraisal can help avoid these complications and support accurate tax reporting.

Investment Accounts Aren’t Always Immune

Many people assume brokerage firms automatically maintain all necessary records forever. While financial institutions often provide valuable documentation, heirs should not assume every historical valuation will remain easily accessible years into the future. Complex portfolios, private investments, and older holdings may require additional records to support tax calculations. A date-of-death valuation package can help consolidate critical information in one place.

Trusts and Wills Do Not Automatically Solve the Problem

Many individuals mistakenly believe that having a trust or will eliminates all future estate administration concerns. In reality, these documents primarily direct how assets are distributed rather than documenting tax basis information. A trust may transfer ownership efficiently, but beneficiaries still need accurate valuation records for tax reporting. Estate planning professionals increasingly recommend creating an asset inventory that includes valuation instructions and appraisal guidance. This additional documentation can complement a will or trust and improve overall tax accuracy.

Family Businesses and Collectibles Require Special Attention

Certain assets present unique valuation challenges. Family businesses, artwork, antiques, rare coins, and collectibles may not have readily available market prices. Determining fair market value often requires specialized appraisals from qualified professionals. If these valuations are not completed near the date of death, beneficiaries may face disputes with tax authorities or uncertainty about future capital gains calculations. Including valuation planning as part of a broader step-up in basis strategy can help prevent these issues.

The Paperwork Detail That Could Protect Your Family’s Future

A well-written will remains an essential estate planning tool, but it is not always enough to ensure tax accuracy for future generations. The step-up in basis can provide substantial tax savings, yet beneficiaries often struggle when proper valuation records are missing. By including date-of-death appraisals, valuation reports, and organized documentation alongside traditional estate planning documents, families can reduce confusion and protect heirs from unnecessary tax complications. Estate planning is ultimately about making life easier for the people you leave behind. Sometimes, the most valuable document is not the will itself, but the paperwork that helps support it when the time comes.

Have you reviewed your estate plan recently, and does it include documentation to support a future step-up in basis? Share your thoughts in the comments below.