Commercial cost segregation produces smaller percentage reclassification than residential STR math (typically 12–25% vs. 25–35%), but three factors make it equally or more lucrative in dollar terms: (1) higher typical basis, (2) 39-year default recovery vs. 27.5, which means more years of accelerated savings, and (3) tenant improvements often qualify as 15-year Qualified Improvement Property (QIP) with 100% bonus depreciation. A $5M commercial property routinely generates $500K+ in Year-1 reclassification.
How Commercial Cost Seg Differs from Residential
Three structural differences shape commercial cost segregation math:
1. 39-year default recovery. Commercial buildings depreciate over 39 years (vs. 27.5 for residential). That means the straight-line annual depreciation is lower as a percentage of basis — so the Year-1 acceleration math is more valuable relative to default treatment. A commercial building's 39-year treatment means $25K/year depreciation on a $1M basis; residential would be $36K/year on the same basis. Cost seg that pulls $200K into Year 1 is therefore more impactful on commercial.
2. Tenant improvements and QIP. Qualified Improvement Property (QIP) — most non-structural interior improvements to commercial building interiors — qualifies as 15-year property eligible for 100% bonus depreciation under the CARES Act and later OBBBA. That's a big deal: every tenant buildout, every LED lighting retrofit, every HVAC replacement (beyond roof-top units mounted externally) can be reclassified into a faster class.
3. Specialty systems dominate the 5- and 7-year buckets. Commercial properties often have specialty HVAC systems, kitchen equipment (in restaurants), dedicated walk-in coolers (grocers), conveyor systems (industrial), dedicated server rooms (office), and other property types that qualify as 5- or 7-year MACRS. These don't exist in residential at all.
Typical reclassification ranges:
- Office: 12–22% (lower if raw "vanilla shell," higher if extensive tenant buildouts)
- Retail: 15–25%
- Restaurant: 25–35% (kitchen equipment dominates)
- Medical office: 20–28% (specialty exam-room fixtures, imaging suites)
- Industrial / warehouse: 10–18% (mostly shell building; process equipment carries separately)
- Mixed-use: Varies; each use computed separately
Example 1: Class-B Office — $1.2M Suburban Multi-Tenant
Atlanta Metro — Class-B Professional Office
A two-story Class-B office building with four professional-services tenants (CPA firm, law practice, medical billing, insurance agency). Recent 2023 HVAC retrofit and 2021 common-area renovation. Moderate tenant-specific fit-outs.
| Component | MACRS Class | Amount |
|---|---|---|
| Specialty tenant fixtures (reception millwork, built-ins) | 5-yr | $18,500 |
| Kitchenette appliances (shared break rooms × 4) | 5-yr | $8,200 |
| IT infrastructure (data room, cabling, racks) | 5-yr | $22,000 |
| Interior finishes (non-structural ceiling, partitions) | QIP 15-yr | $48,000 |
| LED lighting retrofit (2023) | QIP 15-yr | $24,500 |
| Restroom fixtures, plumbing updates | QIP 15-yr | $18,000 |
| Asphalt parking lot, striping, bollards | 15-yr | $42,000 |
| Landscaping, exterior lighting, signage | 15-yr | $19,500 |
| Total reclassified (16.7% of basis) | $200,700 |
Class-B office is the lower-end of commercial reclassification because the building shell is the dominant cost component. Still, at 16.7% reclassification on a $1.2M property with 100% bonus depreciation, the Year-1 tax impact approaches $75K. The QIP bucket ($90K) is the biggest driver — improvements to commercial interiors that now accelerate into 15-year with bonus depreciation.
Example 2: Net-Lease Retail — $3M Strip Center
Tampa, FL — 5-Unit Strip Retail
Neighborhood strip retail with a mix of triple-net (NNN) and gross tenants. One tenant is a full-service restaurant with a commercial kitchen — drives disproportionate share of reclassification. Shared parking, monument sign, and basic landscaping.
| Component | MACRS Class | Amount |
|---|---|---|
| Restaurant tenant: kitchen equipment, walk-in, hood | 5-yr | $95,000 |
| Salon & nail: specialty plumbing, chairs, stations | 5-yr | $42,000 |
| Dry cleaner: specialty ventilation, equipment connections | 5-yr | $28,000 |
| Retail tenant fixtures, POS infrastructure | 5-yr | $18,500 |
| Specialty lighting across all 5 tenants | 5-yr | $22,000 |
| Tenant buildouts (QIP across all 5) | QIP 15-yr | $165,000 |
| HVAC roof-top units × 5 (QIP eligible) | QIP 15-yr | $78,000 |
| Asphalt parking, striping, accessible ramps | 15-yr | $92,000 |
| Landscaping, exterior lighting, monument sign | 15-yr | $48,000 |
| Site improvements: retaining walls, storm drainage | 15-yr | $38,000 |
| Total reclassified (21.9% of basis) | $626,500 |
The restaurant tenant alone drives $95K of 5-year personal property (kitchen equipment + walk-in + hood system). Retail properties with restaurant or food-service tenants routinely outperform office-only properties on reclassification because commercial kitchen equipment is entirely 5-year MACRS. Florida's zero state income tax means no state-level conformity issues — every federal dollar saved stays in the owner's pocket.
Example 3: Industrial / Warehouse — $5M Light Manufacturing
Phoenix, AZ — Light Industrial / Distribution
Single-tenant light industrial building occupied by a metal-fabrication tenant. Typical distribution layout: office at front (15%), warehouse floor (85%). Minimal tenant-specific improvements because the tenant owns their own process equipment (not in the real property basis).
| Component | MACRS Class | Amount |
|---|---|---|
| Front office: finishes, reception, IT cabling | 5-yr | $42,000 |
| Warehouse specialty lighting (high-bay LED) | 5-yr | $28,000 |
| Loading dock equipment (levelers, bumpers, seals) | 5-yr | $38,000 |
| Office interior (QIP since 2017) | QIP 15-yr | $58,000 |
| Office HVAC (rooftop unit, QIP) | QIP 15-yr | $22,000 |
| Asphalt truck court, striping, bollards | 15-yr | $145,000 |
| Fencing (chain-link + motorized gates) | 15-yr | $48,000 |
| Exterior security lighting, CCTV infrastructure | 15-yr | $22,000 |
| Landscaping, drainage, minimal softscape | 15-yr | $18,500 |
| Site work: retaining walls, storm water management | 15-yr | $64,000 |
| Total reclassified (14.5% of basis) | $725,500 |
Industrial reclassification percentages look low (14.5%) because warehouse buildings are mostly tilt-up concrete shell with minimal interior buildout. But 14.5% of $5M is $725K — comparable to the absolute dollar value of Example 2 at 21.9% of $3M. The 15-year site-improvement bucket dominates industrial math: loading-dock infrastructure, truck courts, fencing, and security are all substantial dollar items that don't exist on office or retail at the same scale. Arizona conforms to federal bonus depreciation with no state income tax, so every federal savings dollar flows cleanly.
Commercial Cost Seg: The Passive-Activity Complication
Commercial real estate, like residential rentals, is generally treated as a passive activity under §469 unless the owner qualifies as a Real Estate Professional (REPS) or the property is used in the owner's active trade or business (e.g., owner-occupied medical office where the owner practices). For LP investors in commercial syndications, Year-1 depreciation losses flow through on K-1s but are typically passive-suspended until there's passive income to offset or the property sells.
The workarounds:
- REPS qualification — 750+ hours/year in real property trades, more than 50% of personal services. Strict but possible for full-time investors.
- Active use / material participation — applies to owner-occupiers (doctor in own medical office, dentist in own dental building).
- Grouping election — combining multiple real estate activities to aggregate hours toward REPS threshold. Consult your CPA; this is a specialist's area.
Study Cost for Commercial
Commercial studies price by purchase value:
- Under $1M: $995
- $1M–$2M: $1,395
- $2M–$15M: $1,895
- $15M+: $2,995 (includes complimentary site visit)
Full pricing detail: cost segregation study cost.
Running Commercial Numbers
The cost segregation calculator handles office, retail, restaurant, medical office, industrial, and mixed-use estimates. Plug your purchase price and property type for a Year-1 reclassification estimate in under 30 seconds.
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Office, retail, and industrial component breakdowns, QIP 15-year math, and passive-activity implications for commercial investors.
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