The 30-second answer
Cost segregation and 1031 exchange are not alternatives — they stack. Cost segregation under IRC §168 accelerates depreciation on a property you already own, surfacing 18–32% of basis as Year-1 deduction under 100% bonus depreciation (post-OBBBA). A 1031 exchange under IRC §1031 defers capital gains and depreciation recapture when you sell and replace one property with another within 180 days. Both are tax deferrals; they apply at different moments. The right question isn't "which one?" — it's "which one first, and how do they interact?"
Cost segregation vs. 1031 exchange — side-by-side
| Dimension | Cost Segregation | 1031 Exchange |
|---|---|---|
| Statute | IRC §168, §168(k), Rev. Proc. 87-56 | IRC §1031 |
| Trigger event | Ownership (no sale required) | Sale + replacement purchase |
| Deferral type | Accelerated depreciation (Year-1 deduction) | Capital gains + recapture deferral (no current tax) |
| Holding period | Any (lookback available via Form 3115) | Replacement must be acquired within 180 days; ID within 45 days |
| Typical benefit | $80K–$300K Year-1 federal deduction on $1M–$3M property | Defers capital gains (15–20%) + §1250 recapture (capped 25%) on entire gain |
| Cost / friction | From $495 engineered study | Qualified Intermediary fee $1K–$3K + execution risk |
| Recapture impact | 5/7/15-yr buckets recapture as §1245 ordinary income on disposition | Defers recapture forward to replacement property's basis |
| Best when | You want to use the property's losses against current-year income | You're selling and want to roll basis forward without realizing gain |
How they stack (the right sequence)
The two strategies serve different moments in the holding cycle. A typical playbook for an investor selling Property A and buying Property B looks like this:
- Property A — sell via 1031: Defer capital gains (15–20%) and §1250 recapture (capped 25%) by reinvesting the entire gross sale proceeds into Property B within 180 days. The deferred basis carries forward.
- Property B — order cost segregation immediately: Reclassify 18–32% of Property B's basis into 5/7/15-year MACRS classes. Under 100% bonus depreciation (post-OBBBA), the entire reclassified portion is deductible Year-1. This generates a paper loss that offsets ordinary income (if you qualify under REPS or the STR loophole).
- Net effect: Deferred capital gains on sale + accelerated deduction on purchase = the highest-leverage real estate tax setup available, fully legal, repeatable on every cycle.
When each wins on its own
- Cost segregation alone wins when: you're holding a property long-term, not selling, but want immediate Year-1 deductions. The cost seg study delivers accelerated depreciation without triggering a sale.
- 1031 exchange alone wins when: you're selling and replacing without needing additional current-year deductions. Pure capital-gains deferral.
- Both win together when: selling-and-replacing AND wanting current-year deductions. This is the standard playbook for active multi-property investors.
- Neither wins when: the property has very low depreciable basis (cost seg pencils low) AND there's no embedded gain to defer (1031 unnecessary). Mostly applies to recently-purchased commercial properties at-cost.
Recapture interaction (the technical detail most CPAs miss)
Cost segregation creates §1245 personal-property buckets (5/7/15-yr) and §1250 real-property buckets (27.5/39-yr). §1245 property recaptures at ordinary income rates (up to 37%); unrecaptured §1250 caps at 25%. A 1031 exchange defers ALL recapture forward — including the §1245 ordinary-income recapture from prior cost seg studies. The replacement property inherits the §1245 recapture obligation. This is why many sophisticated investors do cost seg on the purchase side of a 1031 exchange: the new study captures Year-1 deductions but doesn't accelerate the deferred §1245 recapture from the old property. See our recapture explainer and Form 3115 page for the technical math.
What this means for your study
If you're considering a 1031 exchange, talk to your CPA about ordering a cost segregation study on the replacement property the same year you close. The deferred gains from the exchange + the accelerated depreciation from the study is the combined Year-1 tax position. Cost Seg Smart engineered studies start at $495 (residential) / $995 (commercial), produce a CPA-ready 40+ page PDF in under one hour, and include 36 months of audit support. Run your numbers on the free calculator.
Last reviewed: June 2026. For the §168 / §168(k) / §1031 statutory chain and the OBBBA 2025 permanent-bonus restoration in historical context, see cost segregation legal history. Companion comparison pages: cost segregation vs. opportunity zones · cost segregation vs. bonus depreciation alone · main comparison hub.