IRS Revises Publication 551 for 2026, U.S. Property Basis Rules Affect Depreciation

(UNITED STATES) — U.S. taxpayers entering the 2026 filing season are confronting a tax rule that shapes far more than a future sale: property basis, the figure the IRS uses to measure depreciation, amortization, casualty losses, and gain or loss when an asset changes hands.

The issue reaches across a wide group of filers, from NRIs with U.S. rental homes to H-1B professionals who turned former residences into investment property, immigrant founders buying business assets, and investors holding stocks, bonds, or inherited property. In each case, U.S. Property Basis can change annual deductions and the tax bill that comes due years later.

IRS Publication 551, revised in December 2025, remains the main IRS guide on basis. Its rules run through rental property, inherited assets, securities, business acquisitions and involuntary conversions, and they often turn on records taxpayers set aside long before a sale.

Basis is generally the taxpayer’s investment in property for tax purposes. That makes it the starting point for depreciation and other tax calculations, but not the ending point, because the figure can rise or fall over time.

A common mistake is treating basis as the same thing as purchase price. The IRS framework does not do that. Cost usually starts the calculation, but basis can also reflect debt obligations assumed, property transferred, services given, and a range of acquisition costs that have to be capitalized.

For many assets, those costs include commissions and, in some cases, sales tax, freight, installation, and testing. Contract price alone, then, is not a reliable measure of basis, even before later adjustments begin to reduce it.

That matters in practical terms for landlords and investors who use the wrong number in the first year and then carry that error forward. If basis is wrong at the start, depreciation can be wrong, rental deductions can be wrong, and gain or loss reported on a later sale can be wrong as well.

Real estate often produces the clearest example. IRS guidance distinguishes between the cost of buying property and the cost of getting the loan used to buy it, a line many buyers blur when they review closing papers.

For rental property, settlement fees and closing costs can become part of basis. Publication 527 identifies items such as abstract fees, charges for installing utility services, legal fees, recording fees, surveys, transfer taxes, and owner’s title insurance as amounts that can increase basis.

Certain seller liabilities that the buyer agrees to pay can also increase basis in the property. But other charges generally do not. Casualty insurance premiums, rent for occupancy before closing, charges for utilities before closing, and many loan-related costs such as points, mortgage insurance premiums, appraisal fees required by the lender, and refinancing costs are treated differently.

That distinction can change the numbers quickly. A buyer may think every amount on a settlement statement belongs in basis, yet financing costs often follow separate deduction or amortization rules rather than becoming part of the property’s tax basis.

The land-and-building split is another rule with wide effects. When a taxpayer buys real property for a lump sum, basis usually must be allocated between land and building, because land is not depreciable while the building often is.

The allocation should generally follow the relative fair market values of the land and building at acquisition. If those values are not known, assessed values may be used as a practical method.

For rental owners, that allocation shapes depreciation from the first year. Assign too much to land and depreciation is understated. Assign too much to the building and the taxpayer may claim too much depreciation, creating trouble later on audit or sale.

Adjusted basis then changes again as ownership continues. Improvements that add value, prolong life, or adapt property to a different use generally increase basis, while depreciation, certain casualty-loss adjustments, certain credits, and other return-of-capital items reduce it.

That means a property’s basis at sale may look very different from the number that existed at purchase. A room addition, a roof treated as a capital improvement, or a qualifying system can push basis up. Years of depreciation usually push it down.

Market value does not alter that tax figure by itself. A house or rental building may rise sharply in price, but appreciation alone does not increase basis, a point that many owners overlook when they try to estimate gain.

The conversion of a personal residence to rental use adds another rule that often catches taxpayers by surprise. Publication 527 states that when property held for personal use is converted to rental use, the basis for depreciation is generally the lesser of the property’s adjusted basis or fair market value on the date of conversion.

That rule can matter for H-1B workers, green card holders, and NRIs who leave a home and start renting it out. If the property declined in value before the conversion, the owner cannot use the older, higher personal basis to generate larger rental depreciation.

Conversion-year records become central in those cases. Taxpayers often remember what they paid for the house, but the depreciation figure after conversion may instead hinge on the lower of adjusted basis or fair market value on the conversion date.

Inherited property follows a different path. Publication 551 says inherited property generally takes a basis equal to its fair market value at the decedent’s date of death, or an alternate valuation date if properly elected by the estate.

That often produces a step-up in basis when the asset rose in value during the decedent’s lifetime, though a step-down can occur if the value had fallen. For families inheriting U.S. real estate or securities, the heir’s starting basis is often not what the decedent originally paid.

Inherited property also generally gets long-term holding treatment for capital-gain purposes regardless of actual holding period. That rule can shape the tax result when heirs sell soon after inheriting.

Securities bring their own set of basis questions. For stocks and bonds, basis is generally the purchase price plus costs of purchase, including commissions and recording or transfer fees.

Problems often surface when investors buy the same stock in multiple lots over time and later sell only part of the position. In those cases, basis depends on whether the sold shares were properly identified. If they were not, default rules can apply.

Nontaxable stock dividends and stock splits do not change total basis overall. Instead, basis is reallocated across the shares. A return of capital distribution reduces basis, which can raise taxable gain later when the shares are sold.

The same principle extends to business purchases. When a taxpayer buys an entire business for a single purchase price, basis usually must be allocated among the acquired assets rather than assigned to one broad category.

Cash is treated at face amount. The remaining purchase price is allocated among the acquired business assets, and any residual amount generally becomes goodwill or another intangible under the applicable acquisition rules.

For immigrant entrepreneurs buying restaurants, clinics, small manufacturing businesses, or service firms in the United States, that allocation can shape deductions for years. It also affects future gain or loss, depreciation, and amortization.

Involuntary conversions add yet another layer. Publication 544 explains that when property is destroyed, stolen, condemned, or otherwise subject to an involuntary conversion, the basis of replacement property follows special rules.

The basis of replacement property generally depends on the basis of the converted property, recognized gain or loss, the cost of replacement property, and whether the replacement is similar or related in service or use. For rental owners and business taxpayers dealing with casualty events or insurance-driven replacements, the new property may not begin with a fresh cost basis untied to the old one.

Basis can also shrink quietly over time in ways taxpayers forget. Publication 551 lists depreciation, Section 179 deductions, casualty and theft adjustments, easement payments in certain situations, certain credits, and nontaxable corporate distributions among the items that can reduce basis.

Those reductions often drive surprise tax bills. Owners remember purchase price and improvements, but they overlook years of claimed depreciation or other basis reductions, and then understate gain when they sell.

That is why accurate U.S. Property Basis records matter beyond accountants’ workpapers. For NRIs with U.S. real estate, basis shapes rental deductions, depreciation, future FIRPTA-related sale reporting, and long-term gain calculations. For workers who convert a former home into a rental, the rule applied in the first rental year can echo through every return that follows.

Investors face the same recordkeeping pressure. A brokerage statement showing sale proceeds does not, by itself, determine taxable gain or loss. Basis history still controls the calculation.

The same is true for owners who assume rising value means rising tax basis. Under IRS Publication 551, appreciation is not basis. Improvements may raise it. Depreciation and other reductions may lower it. The market alone does neither.

As 2026 returns take shape, the practical lesson for landlords, investors, business buyers and heirs is that basis is not a static figure and not simply a sticker price. It starts with cost, then shifts with acquisition costs, allocations, improvements, depreciation, casualty events, credits, distributions, conversions, inherited-property rules, and other adjustments that can alter tax outcomes years after the original purchase.

For taxpayers claiming depreciation now or preparing to report gain later, that number sits at the center of the calculation. When it is right, returns line up with the IRS rules. When it is wrong, the mistake rarely stays small.