Cost Segregation Before Selling: Does It Help or Hurt?

The study accelerates deductions by changing the character of part of your basis, and the character is what you sell

A cost segregation study identifies parts of a building that qualify as tangible personal property or land improvements and moves their cost out of the 27.5-year or 39-year building class into 5, 7 and 15-year classes. The authority is Hospital Corporation of America v. Commissioner, 109 T.C. 21 (1997), which held that the old investment credit tests still separate section 1245 property from section 1250 property under MACRS; the IRS acquiesced on that point, as its Cost Segregation Audit Techniques Guide records.

Since the July 2025 tax act, Publication 946 confirms a 100% first-year allowance for qualified property acquired and placed in service after January 19, 2025, and section 168(k)(2) defines qualified property as property with a recovery period of 20 years or less. Everything a study reclassifies therefore qualifies, which is why the first-year deduction can be a large share of the purchase price.

The reclassified cost is section 1245 property from then on, and section 1245 recapture applies when you sell: ordinary income up to the depreciation taken on each component. The building you did not reclassify stays section 1250 property, whose straight-line depreciation is unrecaptured section 1250 gain capped at 25% under section 1(h). The study trades the 25% cap for ordinary rates on the reclassified slice in exchange for getting the deduction now.

Selling for cash soon after the study mostly returns the deduction at ordinary rates

Publication 544 requires gain to be figured asset by asset when several assets are sold together, with the selling price allocated among them, and makes the section 1245 ordinary income on each asset the lesser of its depreciation and its gain. If the contract allocates to the components roughly what you deducted on them, the recapture equals the deduction and the character is ordinary on both sides.

A study run in the sale year is the clearest case. The catch-up comes through Form 3115 as a negative section 481(a) adjustment under section 6.01 of Rev. Proc. 2025-23, deducted in full in the year of change, and the sale recaptures it on the same return. Hypothetical: you bought a building in March 2025 for $3,000,000, a 2026 study moves $500,000 into short-lived classes and produces a $500,000 deduction, and a December 2026 sale allocates $500,000 to those components. The $500,000 of ordinary income cancels the deduction, the 25% layer on the rest of the building is unchanged, and the study fee bought a timing effect of zero. The catch-up depreciation page covers that filing in detail.

If the same sale allocates $300,000 to the components, the recapture is $300,000 and the net is a $200,000 ordinary deduction. The allocation is the whole game, and a buyer who plans to depreciate the property wants the opposite allocation. Run your own numbers with your CPA on the allocation before the study, not after.

It helps when the deduction and the recapture fall in different rate years, or when the components have lost value

The benefit of a study is the spread between the rate the deduction saves and the rate the recapture costs, plus the use of the money in between. For 2026, Rev. Proc. 2025-32 places the 37% bracket above $768,700 of taxable income for joint filers and $640,600 for single filers, with 35% from $512,450 and $256,225 respectively. A deduction taken at 37% in a working year and recaptured at 24% in a retirement year is a real gain; the reverse is a real loss.

The second help is physical. Components that wear out, carry low value at sale, and so carry a small share of the price produce recapture capped at that small gain under the lesser-of rule. A study that reclassified items the buyer will replace on day one is the one most likely to come out ahead at sale, provided the allocation reflects that.

The third help is a long hold. A study taken years before any sale has already produced its value in the form of deferred tax, and the recapture at sale is the price of that deferral, not a surprise. The cost segregation and 1031 strategy guide is the planning view of that trade; the bonus depreciation versus 1031 guide compares it with deferring the gain instead.

Exchanging after a study usually triggers the section 1245 layer, so order the study and the exchange carefully

Section 1245(b)(4) limits recapture in a like-kind exchange to the gain recognized plus the fair market value of property acquired that is not section 1245 property. Publication 544 works the example: $10,000 of fully depreciated section 1245 components exchanged for real property worth $100,000 with no cash produces $10,000 of ordinary income even though no gain is recognized under section 1031, because the section 1250 property received exceeds the recapture. A replacement that is mostly building, including most DSTs, therefore recognizes the whole section 1245 layer.

The real property regulations for section 1031 do not change that. Reg. section 1.1031(a)-3(a)(7) states that its definitions apply only for section 1031 and that no inference is intended for sections 1245 and 1250. Recapture not recognized in the exchange attaches to the replacement and is recognized when it is sold at a gain.

The better order is often study second. Reg. section 1.168(i)-6 depreciates the exchanged basis over the relinquished property's remaining schedule and treats any excess basis as property newly placed in service in the year of replacement; a study on the replacement can reclassify that excess basis and take the 100% allowance on it, as the page on bonus depreciation and cost segregation on replacement property explains. The same regulation lets you elect to treat the entire replacement basis as new, which is sometimes worth modeling.

If a study has already been done on the relinquished property, bring the section 1245 schedule to the exchange planning. Matching the recapture with section 1245 property in the replacement, taking the ordinary income in a year when it is cheap, or accepting it as the cost of exiting are all defensible; being surprised by it on the exchange-year return is not.

Where the client's products fit: funds built on accelerated depreciation and DSTs handle the study differently

A fund built around accelerated depreciation runs its own study on property it acquires, and the deductions flow to investors through the fund; the accelerated depreciation funds page describes that structure, and the 1031 into a bonus depreciation fund page explains why exchange proceeds and fund interests do not mix. The recapture rules above apply inside the fund when it sells.

A DST that holds a building is section 1250 property almost entirely, and an investor's exchanged basis keeps the schedule it arrived with under Reg. section 1.168(i)-6. The DST depreciation and bonus page covers what an investor actually deducts; the point here is only that the DST will rarely hold enough section 1245 property to absorb a prior study's recapture.