100% Bonus Depreciation Is Back — Permanently. Here's How to Use It on Your Next Deal.

The IRS Just Made One of Real Estate's Best Tax Moves Permanent. Most Investors Still Haven't Done Anything.

IRS Notice 2026-11 quietly dropped in January, and if you've bought — or plan to buy — any investment property since January 19, 2025, you're sitting on a tax deduction most investors are still leaving on the table. The One Big Beautiful Bill (OBBBA) reversed the entire phasedown on bonus depreciation and made 100% first-year expensing permanent. Treasury confirmed the implementation rules in January. The window is open, and it doesn't close.

Here's what this means in real numbers: on a $500,000 rental property, a standard depreciation schedule nets you roughly $17,425 in year-one deductions. Run a cost segregation study first, and that number jumps to over $91,000 — in the same tax year you close. At a 37% marginal rate, that gap is worth more than $27,000 back in your pocket this year. Not eventually. This year.

If you've closed deals since January 2025 and haven't ordered a cost segregation study, you've been overpaying the IRS. This guide tells you exactly how to fix that.

What Bonus Depreciation Actually Does (and Why 2026 Is Different)

Most investors know the standard 27.5-year depreciation schedule for residential rental properties. Buy a $400,000 building (after land allocation), deduct roughly $14,500 per year over 27.5 years. It works, but it's slow.

Bonus depreciation works differently. The IRS allows certain shorter-lived assets inside a property to be expensed at 100% in the year placed in service — not spread across their 5, 7, or 15-year schedules. This includes HVAC systems, flooring, fixtures, appliances, land improvements, roofing components, and the interior improvements to nonresidential buildings.

The catch: the building itself still depreciates over 27.5 or 39 years. To access bonus depreciation on those shorter-lived components, you need a cost segregation study — an engineering-based analysis that breaks your property into its depreciable parts and identifies which ones qualify for accelerated treatment.

This is not new. Cost segregation has existed for decades. What changed is the rate. From 2023 through early 2025, Congress was phasing bonus depreciation down — 80%, then 60%, then 40%. The OBBBA reversed the entire phasedown effective January 19, 2025, and made 100% permanent with no expiration date. IRS Notice 2026-11 (issued January 14, 2026) established the specific rules and component election procedures investors need to file correctly.

Every property you've acquired since that date lives under the new permanent rules. Every property you close from here on does too.

The Numbers

Here's what the math looks like on actual deal sizes, using data from current cost segregation practitioners and IRS Notice 2026-11 guidance.

Single-family rental, $500,000 purchase price

• Depreciable basis after land allocation: $400,000
• Standard 27.5-year depreciation, year 1: $17,425
• After cost segregation study (20% of basis to short-lived assets):
  • 5/7/15-year assets: $80,000 → 100% bonus depreciation = $80,000
  • Remaining structure: $320,000 → 27.5 year = $11,636
  • Year-1 total: $91,636 — a 5x increase
• Tax savings at 37% federal rate: ~$27,380 in year one
• Cost segregation study fee: $5,000–$12,000
• Net first-year benefit: $15,000–$22,000 after the study cost

That's a 3-6x return on the study fee alone, in the first year.

Multifamily, $4.5M acquisition The Primior Group documented a 2026 case study where a multifamily investor generated $306,250 in federal tax savings through a cost segregation study combined with 100% bonus depreciation on the eligible components. At that scale, study fees become near-trivial relative to the outcome.

Section 179 also got bigger. The OBBBA raised the Section 179 immediate expensing limit from $1.25M to $2.5M, with phase-out now starting at $4M in qualifying purchases. For commercial property investors with equipment-heavy acquisitions, this is an additional lever worth running past your CPA alongside the bonus depreciation analysis.

One critical caveat from IRS Notice 2026-11: the 100% rate applies only to property placed in service after January 19, 2025. For self-constructed or substantially renovated properties, "underway" is defined as significant physical work beginning or more than 10% of total project costs being incurred after that date. If you're straddling this date on a rehab, the component election strategy in Notice 2026-11 allows you to apply 100% to individual components placed in service after the cutoff — even if the overall project started earlier.

Common Mistakes Investors Make Here

• Waiting on the study until year-end. The cost segregation study must be complete to file the deduction. Investors who plan to "get it done eventually" often miss it entirely on their first deal. Order the study within 60 days of acquisition.

• Applying 100% to properties acquired before January 19, 2025. The permanent 100% rate only covers the new law. Properties acquired between 2023 and early 2025 are under the old phasedown schedule (40% in 2025). Don't assume every property qualifies for the full rate.

• Ignoring state tax nonconformity. Several states — California being the most significant — do not conform to federal bonus depreciation rules. Your federal deduction may generate a state add-back, partially offsetting the benefit. Always model the state impact alongside the federal analysis.

• Skipping REPS analysis. Unless you qualify as a Real Estate Professional (750+ hours/year, with real estate as your primary activity), bonus depreciation losses are passive and can only offset passive income. For W-2 earners, the losses accumulate and are released at disposition — still valuable, but the timing differs. Run your REPS status analysis before assuming the deduction hits this year's taxable income.

How to Use PropGPT for This

This strategy lives or dies on accurate deal modeling. PropGPT accelerates every step — from quickly sizing the opportunity during due diligence to structuring the full 10-year after-tax return.

"I'm buying a $650,000 single-family rental. The property has a new HVAC system, in-ground pool, detached garage with concrete driveway, hardwood floors throughout, and updated kitchen appliances. Walk me through how a cost segregation study would categorize each component and estimate my total year-1 bonus depreciation deduction."

Use this before you hire an engineer. It gives you a component-level estimate in minutes so you can decide whether commissioning the full study is worth it — and shows up to your CPA prepared.

"Model a $750,000 rental property acquisition with and without a cost segregation study. Assume: 20% of depreciable basis qualifies for 5-year bonus depreciation, 37% marginal tax rate, $10,000 study cost, 4% annual appreciation, 6.2% mortgage rate, 5% cap rate. Show year-by-year cash-on-cash after tax for 10 years."

This is the full picture — turning a tax deduction into an IRR comparison. Run this on any deal before deciding whether to commission the study.

"I have $180,000 in passive losses from bonus depreciation on three rental properties acquired in 2025. I am not a real estate professional (W-2 income of $240,000). How will these losses be used, when do they release, and what's the present-value benefit assuming a 7% discount rate and 10-year hold?"

For non-REPS investors, this prompt quantifies the deferred benefit — which is still substantial, just not immediate. Essential for understanding your actual after-tax position.

"I'm purchasing a 24-unit apartment building for $2.2M. What percentage of the purchase price typically qualifies for 5-year, 7-year, and 15-year asset categories in a multifamily cost segregation study? Give me a conservative range and an aggressive range based on current IRS guidance."

Size the multifamily opportunity quickly during due diligence, before committing to a formal study. Use the range to bracket your expected tax benefit.

"I want to use bonus depreciation to significantly offset my $320,000 in W-2 income this year. I'm considering acquiring a rental property. Walk me through the exact steps: what I need to buy, what elections I need to file, whether I should pursue Real Estate Professional Status, and what my realistic maximum deduction is."

For high-income investors who came to real estate partly for tax efficiency — this prompt turns a vague goal into a specific acquisition and filing plan.

The Bottom Line

The permanent reinstatement of 100% bonus depreciation is the most significant structural change to real estate tax strategy since the 2017 Tax Cuts and Jobs Act. IRS Notice 2026-11 settled the implementation rules in January 2026, and every deal you've closed since January 19, 2025 either already used this — or has an unfiled deduction waiting.

The math is simple: on a $500K rental, a $10,000 cost segregation study generates $27,000+ in year-one federal tax savings. Net benefit in year one: $15,000–$22,000. The study pays for itself multiple times over before you've made your second mortgage payment.

Run the PropGPT prompts above to size the opportunity on anything in your current pipeline. Bring the numbers to your CPA. Order the study within 60 days of your next close. The IRS made this permanent for a reason — don't leave the benefit sitting there unclaimed.