Cost segregation for short-term rentals: the tax savings on an STR or vacation rental in 2026

Cost segregation applies to any depreciable building held for business or investment use, and residential rental property is squarely inside that. What people call the STR loophole is simply this tax strategy applied to a short-term rental activity.

What decides the outcome is the passive activity rules. If the average guest stay is seven days or less and you materially participate in the rental activity, the resulting rental losses are not passive and can offset other income, including W-2 income. If you do not, the study still runs, the tax deductions are still real, and they sit suspended until you have passive income or you sell. Short-term rental owners who skip this step buy a report rather than a tax benefit.

So the sequence matters. Confirm participation first, order the study second. The full test is on the short-term rental rules for W-2 earners.

A residential building depreciates over 27.5 years. An engineering-based study separates out the parts that are not really the building and assigns them shorter lives.

This is where a short-term rental differs from ordinary rental properties. A furnished property bought turnkey carries a much larger share of its cost in items on 5, 7 and 15-year lives, so the reclassifiable percentage tends to run higher than on an unfurnished long-term rental of the same price. That is the core of the cost segregation benefits here: more of the purchase price accelerates into the first tax year, which reduces taxable income and improves cash flow while the rental income ramps up.

Not everything needs a study to move quickly. The de minimis safe harbor under Treasury regulation 1.263(a)-1(f) lets a taxpayer without an applicable financial statement deduct up to $2,500 per invoice or item outright, which already covers a lot of what you buy to furnish a unit.

The study reclassifies. Bonus depreciation is what lets you deduct the reclassified amount immediately rather than over five or fifteen years.

Under Section 168(k) as amended by the One Big Beautiful Bill Act, the IRS describes a permanent 100 percent additional first year depreciation deduction for qualified property acquired after January 19, 2025. Notice 2026-11, issued on January 14, 2026, also lets a taxpayer elect a reduced 40 percent rate, or 60 percent for certain longer-production property, instead of the full amount.

That election matters more than it sounds. Taking the whole deduction in a year when your income is low, or when the loss cannot be used, wastes it. Electing down can be the better answer.

The rate history and what New Jersey does with it are on bonus depreciation in 2026.

You do not have to do this in the year you buy. If you have owned the rental for several years and never had a study, you can catch up the depreciation you could have claimed.

It is handled as a change in accounting method on Form 3115, with a section 481(a) adjustment that brings the missed depreciation into the current year. You do not amend the earlier returns. The IRS sets out how examiners review these in its Cost Segregation Audit Techniques Guide, Publication 5653.

Acceleration is a timing decision, not a permanent exemption. When you sell, depreciation on the reclassified personal property comes back as ordinary income under the section 1245 recapture rules, and depreciation on the building is recaptured under section 1250.

Two things soften it. Deducting at today's marginal rate and paying later is worth real money on its own. And a 1031 exchange defers the whole question if you roll into another property rather than cashing out.

What a New Jersey closing adds on top of that is covered on 1031 exchanges in New Jersey.

New Jersey does not follow the federal treatment, and a study is where the gap becomes largest.

New Jersey decoupled from federal bonus depreciation for gross income tax purposes in 2004 and caps the Section 179 deduction at $25,000. The difference between the federal and New Jersey depreciation is tracked on Form GIT-DEP, and the result is that your New Jersey adjusted basis in the property stops matching your federal basis.

Then there is where the loss can land. New Jersey taxes income by category, and a loss in the rents and royalties category does not offset wages. Schedule NJ-BUS-2 permits netting across four business categories at 50 percent, with a 20-year carryforward, and wages are not among them.

None of this is a reason to skip the study. It is the reason the New Jersey saving is smaller than the federal one, and the reason a quote showing a single blended number is worth questioning.