IRS guidance · 1999
A.O.D. 1999-008 (HCA acquiescence)
A.O.D. 1999-008, 1999-2 C.B. xvi
IRS administrative guidance
Audio summary
A short audio walkthrough of this rule: what it says and why it matters for your study.
What it holds
The IRS acquiesced in part to the Hospital Corporation of America decision. The IRS accepted the core principle that Investment Tax Credit era tests for identifying tangible personal property apply when classifying building components under modern MACRS. Component-level depreciation is a valid approach. The IRS reserved the right to dispute specific asset classifications in future cases.
Why it matters for your study: This is the IRS's own official acknowledgment that cost segregation works. Before this notice, practitioners debated whether the IRS would fight the entire practice. After it, that debate ended. The government's own record says the method is valid. Every study rests on the authority chain that runs through this notice.
Where this comes from
When a court rules against the IRS, the agency gets to decide how to respond. It can accept the outcome, keep fighting the same issue elsewhere, or accept part and reject part. That response comes in an official notice called an Action on Decision.
In 1997, the Tax Court ruled for the taxpayer in Hospital Corporation of America. The court said buildings can be broken into components, and components that function like equipment can be depreciated faster under MACRS. Two years later, the IRS responded with A.O.D. 1999-008.
What it established
The IRS acquiesced in part. It accepted the core principle: the tests used during the Investment Tax Credit era to identify tangible personal property also apply when classifying building components under the modern MACRS depreciation system. The bridge from old law to new law holds.
The IRS did not surrender completely. It reserved the right to challenge specific asset classifications in future cases. But the foundational question, whether component-level depreciation is a valid approach at all, the IRS answered yes.
That is why cost segregation studies include this notice in their authority sections. It is the IRS's own record showing that the practice is legitimate.
How it shows up in a study
Before this notice, a skeptic could have argued that HCA was just one court decision, that the IRS would fight the entire idea of cost segregation, and that every study was building on uncertain ground.
After this notice, that argument is gone. The IRS officially accepted the method. On exam, the question is not whether cost segregation is allowed. The question is whether this specific classification, on this specific property, is supported by the facts and the law. That is a narrower fight, and a well-prepared study can win it.
What it does not mean
This notice does not guarantee that any specific classification will be accepted. The IRS explicitly kept the right to contest individual asset decisions. Equipment-serving HVAC, specialty plumbing, and process-specific electrical can still be challenged if the facts are thin.
The notice is also not a statute or a regulation. It is the IRS's informal statement of its litigation position. It does not bind the courts. But it does tell you that when the IRS audits a study, the examiner's job is to check specific classifications, not to challenge the entire practice.
Primary source
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This page explains a tax authority in plain words. It is not tax advice for your situation. The way this authority applies to your property is reviewed by a licensed tax professional. Citation is provided so you or your advisor can read the primary source.