Cost Segregation: MACRS Reclassification and § 481(a) Catch-Up

Cost segregation reclassifies components of a building from § 1250 real property into § 1245 personal property (and into 15-year land improvements), shortening the recovery period under § 168 and accelerating depreciation. The legal framework is anchored by Hospital Corp. of America v. Commissioner, 109 T.C. 21 (1997), and the IRS Cost Segregation Audit Techniques Guide.

The framework

Under § 168(e), residential rental property is 27.5-year and nonresidential real property is 39-year recovery, both under the straight-line method, mid-month convention. Tangible personal property is generally 5- or 7-year under the 200% DB method. Land improvements are 15-year under 150% DB. The classification turns on whether a component is a structural component of the building or tangible personal property.

HCA, 109 T.C. 21, imported the pre-ACRS investment tax credit case law (including Whiteco Industries, 65 T.C. 664 (1975), and Scott Paper Co.) into the MACRS analysis. CCA 199921045 confirms there is no bright-line test; permanence, removability, damage on removal, design function, and intended-vs.-actual use are weighed. The IRS Cost Segregation Audit Techniques Guide formalizes the agent-facing review.

Asset class detail

• 5-year property: carpet, cabinets not part of the structural design, decorative lighting, accent millwork, specialty plumbing serving equipment rather than the building (e.g., kitchen plumbing in a restaurant), some signage.
• 7-year property: office furniture and fixtures not built in.
• 15-year property (land improvements): sidewalks, curbs, parking lots and striping, fencing, site lighting, landscaping, retaining walls.
• 27.5- or 39-year property: the building shell, structural framing, roof structure (note: roof covering may be partially eligible for partial-disposition treatment), permanent HVAC, plumbing serving the building, fire protection.

Bonus depreciation pairing

Under § 168(k) as amended by the TCJA, both new and used property with a recovery period of 20 years or less is eligible for bonus depreciation. The percentage is phasing down: 80% for property placed in service in 2023, 60% in 2024, 40% in 2025, 20% in 2026, 0% in 2027 absent legislation. The cost seg reclassification dropping components into the 5/7/15-year buckets is what makes the bonus available.

For used property acquired in a like-kind exchange or involuntary conversion, § 168(k)(2)(E)(ii) permits the carryover basis to be bonused so long as the related party rules are not tripped.

The 3115 catch-up

For property placed in service in a prior year and depreciated under an impermissible method (here, treating the whole building as 27.5- or 39-year when components were properly 5/7/15-year), the change is a change in method of accounting under § 446(e). CC-2004-007 established the IRS’s litigating position. The taxpayer files Form 3115 under the automatic consent procedures of Rev. Proc. 2015-13 (and the current automatic method change list, presently Rev. Proc. 2024-23), using designated change number 7 (change from impermissible to permissible method of depreciation). The § 481(a) adjustment is negative (additional depreciation) and is taken in full in the year of change.

This is not an amendment, so the statute of limitations on the prior years does not constrain it; the catch-up is recognized in the current year. The catch-up creates ordinary deductions, which then route through the same § 469 passive/non-passive analysis as the originally-allowed depreciation.

Partial asset dispositions

A cost seg also fuels partial-asset-disposition elections under § 1.168(i)-8(d)(2). When a building component is replaced (a roof, an HVAC unit, parking lot resurfacing), the adjusted depreciable basis of the disposed portion can be written off in the year of disposition if the election is made on a timely-filed original return. Without the cost seg detail, the allocation of basis to the disposed portion is harder to defend. See the partial asset disposition article.

Audit posture

The IRS scrutinizes cost seg quality. The defensible posture: (i) engineering-based methodology consistent with the Cost Segregation ATG; (ii) physical site inspection; (iii) review of construction documents, invoices, AIA documents; (iv) qualified preparer (engineering credentials, tax knowledge); (v) detailed asset-by-asset narrative tied to acceptable categorizations. Rule-of-thumb percentage allocations without component-level support are an audit magnet.

When the strategy does not pay

Cost seg accelerates deductions; it does not create them. If the resulting loss is passive and the taxpayer has no current passive income or REPS / STR active classification, the loss is suspended under § 469(a) and the time value is impaired. NPV the study fee against the deferred tax benefit at the client’s discount rate, factor in expected hold period and recapture (§ 1245 on the personal-property components is full ordinary recapture, often more painful than § 1250), and weigh against AMT and excess business loss limitations.