A cost segregation report is a bridge document: engineering analysis on one side, tax return entries on the other. Knowing what belongs in it helps you judge quality before you pay, and knowing how a preparer consumes it explains why the asset detail matters more than the glossy summary pages.
What a quality report contains
The IRS Cost Segregation Audit Techniques Guide describes the elements examiners look for in a quality study. In practice a strong report includes an executive summary with the reclassification totals, a methodology section explaining how costs were determined, the preparer's qualifications, a description of the property and the inspection evidence, a defensible land allocation, legal support for the classifications, and the heart of the document: a detailed asset schedule listing each component, its cost, and its MACRS class under IRS Publication 946. That schedule separates 5-year property such as carpet, appliances, and dedicated electrical, 7-year property such as certain furniture and equipment, 15-year land improvements such as paving, fencing, and landscaping, and the residual 27.5-year residential or 39-year nonresidential building. The report should also reconcile: every allocated dollar must tie back to total depreciable basis.
How the preparer uses it
Your preparer loads the asset schedule into the fixed-asset system as individual assets with their own lives and methods. The 5, 7, and 15 year property is tested for bonus depreciation under IRC section 168(k), at 100% for qualified property acquired after January 19, 2025 under OBBBA, or at the phase-down rate for earlier acquisitions. Current-year placements flow to Form 4562. If the study is a look-back on a property already on filed returns, the preparer instead computes the section 481(a) catch-up, the difference between depreciation actually claimed and what the study supports, and reports it through Form 3115 under the automatic change procedures in the Form 3115 instructions, with no amended returns.
A worked example
On a $2,000,000 medical office placed in service in 2026, the report allocates $300,000 to land, $320,000 to 5-year property, $180,000 to 15-year land improvements, and $1,200,000 to the 39-year building. The preparer books roughly 170 separate assets, takes 100% bonus on the $500,000 of short-life property under section 168(k), and depreciates the building straight-line. Without the asset-level detail, none of that is possible, and neither is a later partial asset disposition when a component is replaced.
Caveats
A report is not self-executing. Someone still has to keep the schedule consistent year over year, handle recapture classes correctly at sale, and defend the file if examined. Amadae does not write these reports and does not employ engineers; it screens the property first so you know the study is worth buying, then ingests the finished report, builds the MACRS schedules, prepares Form 3115 when a catch-up applies, and files the return. Keep the full report with your permanent tax records, since it is your primary audit support.